<%BANNER%>

Improving the Productivity of Livestock with Warm-Season Legumes

Permanent Link: http://ufdc.ufl.edu/UFE0022019/00001

Material Information

Title: Improving the Productivity of Livestock with Warm-Season Legumes
Physical Description: 1 online resource (173 p.)
Language: english
Publisher: University of Florida
Place of Publication: Gainesville, Fla.
Publication Date: 2008

Subjects

Subjects / Keywords: bahiagrass, digestibility, grazing, haylage, intake, legume, retention
Animal Sciences -- Dissertations, Academic -- UF
Genre: Animal Sciences thesis, Ph.D.
bibliography   ( marcgt )
theses   ( marcgt )
government publication (state, provincial, terriorial, dependent)   ( marcgt )
born-digital   ( sobekcm )
Electronic Thesis or Dissertation

Notes

Abstract: The first experiment aimed to determine the herbage mass production and nutritive value of pigeonpea (Cajanus cajan (L.) Millsp. cv. Georgia two), cowpea (Vigna unguiculata (L.) Walp. cv. Iron clay), and soybean (Glycine max (L.) Merr. cv. Pioneer 97B52) in North Florida. When harvested at respective maturity stages that maximized nutritive value and herbage mass, soybean and pigeonpea produced greater (P < 0.01) herbage mass than cowpea, whereas the CP concentrations and in vitro true digestibility (IVTD) of cowpea and soybean were greater (P < 0.05). Another experiment examined the nutritive value, fermentation characteristics, and aerobic stability of cowpea, pigeonpea, annual (Arachis hypogaea L. cv. Florida MDR 98) and perennial (Arachis glabrata Benth. cv. Florigraze) peanut, and bahiagrass (Paspalum notatum Fl?gge) haylages. Perennial and annual peanut and cowpea haylages had normal pH values but other haylages had high values. Yeast and mold counts were low and aerobic stability was at least 84 h in all haylages. Pigeonpea and bahiagrass haylages had lower IVTD (P < 0.05) than the others. In additional experiments, hays and haylages made from these legumes were supplemented (50% of diet DM) to bahiagrass hay or haylage in lamb diets. Perennial peanut and annual peanut hays or haylages were the best supplements because they resulted in the greatest (P < 0.05) intakes, greater digestion of DM and OM, and greater N retention than the control diet. Soybean hay and cowpea hay or haylage were also promising supplements because they increased (P < 0.05) DM and OM intake and N retention versus the control diet. Pigeonpea hay or haylage did not improve (P < 0.05) intake or digestion of DM or OM. A final experiment examined effects of creep feeding cowpea, concentrate, or perennial peanut to cow-calf pairs on bahiagrass pasture. Calves creep grazing cowpea and those creep-fed the concentrate tended (P < 0.10) to have greater ADG. Supplementing with each warm-season legume, except pigeonpea, improved the performance of ruminants fed basal bahiagrass diets. Annual and perennial peanut were the most promising stored legumes, and cowpea showed more promise than perennial peanut when creep-grazed.
General Note: In the series University of Florida Digital Collections.
General Note: Includes vita.
Bibliography: Includes bibliographical references.
Source of Description: Description based on online resource; title from PDF title page.
Source of Description: This bibliographic record is available under the Creative Commons CC0 public domain dedication. The University of Florida Libraries, as creator of this bibliographic record, has waived all rights to it worldwide under copyright law, including all related and neighboring rights, to the extent allowed by law.
Thesis: Thesis (Ph.D.)--University of Florida, 2008.
Local: Adviser: Adesogan, Adegbola T.
Local: Co-adviser: Carter, Jeffrey N.
Electronic Access: RESTRICTED TO UF STUDENTS, STAFF, FACULTY, AND ON-CAMPUS USE UNTIL 2009-05-31

Record Information

Source Institution: UFRGP
Rights Management: Applicable rights reserved.
Classification: lcc - LD1780 2008
System ID: UFE0022019:00001

Permanent Link: http://ufdc.ufl.edu/UFE0022019/00001

Material Information

Title: Improving the Productivity of Livestock with Warm-Season Legumes
Physical Description: 1 online resource (173 p.)
Language: english
Publisher: University of Florida
Place of Publication: Gainesville, Fla.
Publication Date: 2008

Subjects

Subjects / Keywords: bahiagrass, digestibility, grazing, haylage, intake, legume, retention
Animal Sciences -- Dissertations, Academic -- UF
Genre: Animal Sciences thesis, Ph.D.
bibliography   ( marcgt )
theses   ( marcgt )
government publication (state, provincial, terriorial, dependent)   ( marcgt )
born-digital   ( sobekcm )
Electronic Thesis or Dissertation

Notes

Abstract: The first experiment aimed to determine the herbage mass production and nutritive value of pigeonpea (Cajanus cajan (L.) Millsp. cv. Georgia two), cowpea (Vigna unguiculata (L.) Walp. cv. Iron clay), and soybean (Glycine max (L.) Merr. cv. Pioneer 97B52) in North Florida. When harvested at respective maturity stages that maximized nutritive value and herbage mass, soybean and pigeonpea produced greater (P < 0.01) herbage mass than cowpea, whereas the CP concentrations and in vitro true digestibility (IVTD) of cowpea and soybean were greater (P < 0.05). Another experiment examined the nutritive value, fermentation characteristics, and aerobic stability of cowpea, pigeonpea, annual (Arachis hypogaea L. cv. Florida MDR 98) and perennial (Arachis glabrata Benth. cv. Florigraze) peanut, and bahiagrass (Paspalum notatum Fl?gge) haylages. Perennial and annual peanut and cowpea haylages had normal pH values but other haylages had high values. Yeast and mold counts were low and aerobic stability was at least 84 h in all haylages. Pigeonpea and bahiagrass haylages had lower IVTD (P < 0.05) than the others. In additional experiments, hays and haylages made from these legumes were supplemented (50% of diet DM) to bahiagrass hay or haylage in lamb diets. Perennial peanut and annual peanut hays or haylages were the best supplements because they resulted in the greatest (P < 0.05) intakes, greater digestion of DM and OM, and greater N retention than the control diet. Soybean hay and cowpea hay or haylage were also promising supplements because they increased (P < 0.05) DM and OM intake and N retention versus the control diet. Pigeonpea hay or haylage did not improve (P < 0.05) intake or digestion of DM or OM. A final experiment examined effects of creep feeding cowpea, concentrate, or perennial peanut to cow-calf pairs on bahiagrass pasture. Calves creep grazing cowpea and those creep-fed the concentrate tended (P < 0.10) to have greater ADG. Supplementing with each warm-season legume, except pigeonpea, improved the performance of ruminants fed basal bahiagrass diets. Annual and perennial peanut were the most promising stored legumes, and cowpea showed more promise than perennial peanut when creep-grazed.
General Note: In the series University of Florida Digital Collections.
General Note: Includes vita.
Bibliography: Includes bibliographical references.
Source of Description: Description based on online resource; title from PDF title page.
Source of Description: This bibliographic record is available under the Creative Commons CC0 public domain dedication. The University of Florida Libraries, as creator of this bibliographic record, has waived all rights to it worldwide under copyright law, including all related and neighboring rights, to the extent allowed by law.
Thesis: Thesis (Ph.D.)--University of Florida, 2008.
Local: Adviser: Adesogan, Adegbola T.
Local: Co-adviser: Carter, Jeffrey N.
Electronic Access: RESTRICTED TO UF STUDENTS, STAFF, FACULTY, AND ON-CAMPUS USE UNTIL 2009-05-31

Record Information

Source Institution: UFRGP
Rights Management: Applicable rights reserved.
Classification: lcc - LD1780 2008
System ID: UFE0022019:00001


This item has the following downloads:


Full Text

PAGE 1

1 IMPROVINGTHEPRODUCTIVITYOFLIVESTOCKWITHWARM SEASONLEGUMES By JAMIELEEFOSTER ADISSERTATIONPRESENTEDTOTHEGRADUATESCHOOL OFTHEUNIVERSITYOFFLORIDAINPARTIALFULFILLMENT OFTHEREQUIREMENTSFORTHEDEGREEOF DOCTOROFPHILOSOPHY UNIVERSITYOFFLORIDA 2008

PAGE 2

2 2008JamieLeeFoster

PAGE 3

3 Tomybrother,WilliamKentFoster (February20,1982toMarch26,2006)

PAGE 4

4 ACKNOWLEDGMENTS Withoutthestrengthandsupportofmyfamily,especiallymyparentsBarryandSylvia Foster,Iwouldnothavebeenabletocompletemyeducation.Theyunconditionallysupported alloftheimportantlifedecisionsIhavebeenfacedwith. Mybrother,WillyFoster,wasamajor sourceofmotivationtofinishthisdegree.Thebestwaytohonorhismemoryistolivelifetoall ofitspotential. Mysupervisorycommitteemembersservedaswonderfulmentorsbothprofessionallyand personally. Drs.AdegbolaAdesoganandJeffreyCarter,mycommitteecochairs,spentcountless hoursdesigningandimplementingtheseexperimentsandteachingmehowtobearesourceful ruminantnutritionist.Dr.LynnSollenbergerwasaphenomenalforageagronomyins tructor,and hislessonswerehelpfulindesigningthisproject.Drs.AnnBlountandBobMyeroffered necessaryinsightandadvicethatwasinstrumentalincompletingthisresearchproject Withoutthehelpofgraduatestudentsandlaboratorytechnicians inDr.AdesoganandDr. Carterslabs,these labor intensiveproje ctswouldnothavebeenpossible Therefore,Iwould liketothankKathyArriola,MegBrew,SusanChikagwa Malunga,DervinDean,JulietEckert, MaxHuisden,TaewonKang,Sam ChurlKim,Nath anKrueger,MaryMaddox,SergeiSennikov, ReynaSpeckmann,andNancyWilkinsonfortheirassistance.SpecialthankstoMaryMaddox forallofhertimeinthefield,withoutwhommytimeinMariannawouldhavebeenlessefficient andentertaining.Marybe cameapartnerinthisresearchandItreasureherfriendshipand support.SpecialthankstotheFloridaPerennialPeanutProducersAssociationfordonatingand plantingperennialpeanutsprigsandtoDr.PhatakattheUniversityofGeorgiaforthedonatio n ofpigeonpeaseeds.Withoutthesupportandfriendshipoffellowgraduatestudentsandfriends, thementalaspectofgraduateschoolwouldhavebeenunbearable.Itwaswonderfulspending

PAGE 5

2 timewithCristinaCaldari Torres,SindyInter r ante,SummerHough ton,SergioMadrid,Kelly Vineyard,MortVineyard,BeckyWilliams,andJackieWahrmund.Thisgroupbecameafamily awayfromhome.

PAGE 6

6 TABLEOFCONTENTS page ACKNOWLEDGMENTS ................................ ................................ ................................ ............... 4 LISTOFTABLES ................................ ................................ ................................ ......................... 10 LISTOFFIGURES ................................ ................................ ................................ ....................... 12 ABSTRACT ................................ ................................ ................................ ................................ ... 16 CHAPTER 1 INTRODUCTION ................................ ................................ ................................ .................. 18 2 LITERATUREREVIEW ................................ ................................ ................................ ....... 21 Warm SeasonGrassPhotosynthesis ................................ ................................ ....................... 21 Physiology ................................ ................................ ................................ ....................... 21 Anatomy ................................ ................................ ................................ .......................... 22 DigestioninRuminants ................................ ................................ ................................ .......... 24 TheRuminantandWarm SeasonGrasses ................................ ................................ ...... 24 Intake,DegradationandPassage ................................ ................................ ..................... 25 RumenMicrobialGrowt h ................................ ................................ ................................ 25 RuminantversusMicrobialNutrientRequirements ................................ ........................ 27 Bahiagrass ................................ ................................ ................................ ............................... 29 AgronomicCharacteristics ................................ ................................ .............................. 29 NutritiveValue ................................ ................................ ................................ ................ 30 LegumeSu pplementation ................................ ................................ ................................ ....... 31 EffectsonIntakeandDigestibility ................................ ................................ .................. 31 CondensedTannins ................................ ................................ ................................ ......... 33 Warm SeasonLegumesasLivestockFeeds ................................ ................................ ... 34 PerennialPeanu t ................................ ................................ ................................ .............. 35 SeededWarm SeasonLegumes ................................ ................................ ...................... 37 Annual P eanut ................................ ................................ ................................ .......... 37 Soybean ................................ ................................ ................................ .................... 38 Cowpea ................................ ................................ ................................ ..................... 40 Pigeonpea ................................ ................................ ................................ ................. 41 3 FORAGEPRODUCTIONANDNUT RITIVEVALUEOFTHREEWARM SEASON LEGUMES ................................ ................................ ................................ ............................. 45 Introduction ................................ ................................ ................................ ............................. 45 MaterialsandMethods ................................ ................................ ................................ ........... 47 FieldPreparationandForageSa mpling ................................ ................................ .......... 47 SampleCollectionandChemicalAnalyses ................................ ................................ ..... 48 StatisticalAnalyses ................................ ................................ ................................ .......... 48

PAGE 7

7Results.....................................................................................................................................49WholePlantHerbageMassandLeaf-to-stemRatio.......................................................49ChemicalCompositionandIVTD...................................................................................50Discussion...............................................................................................................................56WholePlantHerbageMassandLeaf-to-StemRatio.......................................................56ChemicalCompositionandIVTD...................................................................................574WARM-SEASONLEGUMEHAYORSOYBEANMEALSUPPLEMENTATIONEFFECTSONTHEPERFORMANCEOFLAMBS.............................................................60Introduction.............................................................................................................................60MaterialsandMethods...........................................................................................................61ForageProduction...........................................................................................................61Animals,FeedingandHousing.......................................................................................62SampleCollection...........................................................................................................63ChemicalAnalyses..........................................................................................................64StatisticalAnalyses..........................................................................................................65Results.....................................................................................................................................66ForageChemicalComposition........................................................................................66IntakeandDigestibility...................................................................................................66NitrogenUtilizationandPlasmaMetabolites..................................................................67RuminalFluidpH,NH3-NandVFA...............................................................................70Discussion...............................................................................................................................705NUTRITIVEVALUEANDFERMENTATIONCHARACTERISTICSOFENSILEDWARM-SEASONLEGUMESANDBAHIAGRASS..........................................................76Introduction.............................................................................................................................76MaterialsandMethods...........................................................................................................77ForageProduction...........................................................................................................77ChemicalAnalyses..........................................................................................................79StatisticalAnalyses..........................................................................................................80Results.....................................................................................................................................81ChemicalCompositionofPre-ensiledForages...............................................................81ChemicalCompositionofHaylages................................................................................82FermentationIndices,MicrobialCountsandAerobicStability......................................83Discussion...............................................................................................................................83ChemicalComposition....................................................................................................83FermentationIndices,MicrobialCountsandAerobicStability......................................846WARM-SEASONLEGUMEHAYLAGEORSOYBEANMEALSUPPLEMENTATIONEFFECTSONTHEPERFORMANCEOFLAMBS.....................87Introduction.............................................................................................................................87MaterialsandMethods...........................................................................................................88ForageProductionandEnsiling......................................................................................88Animals,FeedingandHousing.......................................................................................89

PAGE 8

8 SampleCollection ................................ ................................ ................................ ........... 90 ChemicalAnalyses ................................ ................................ ................................ .......... 91 StatisticalAnalyses ................................ ................................ ................................ .......... 92 Results ................................ ................................ ................................ ................................ ..... 92 For ageChemicalComposition ................................ ................................ ........................ 92 IntakeandDigestibility ................................ ................................ ................................ ... 93 NitrogenUtilizationandBloo dMetabolites ................................ ................................ ... 94 RuminalFluidpH,NH 3 NandVFA ................................ ................................ ............... 97 Discussion ................................ ................................ ................................ ............................... 97 7 EFFECTSOFCREEPFEEDINGORCREEPGRAZINGWARM SEASON LEGUMESONTHEPERFORMANCEOFBEEFCATTLE ................................ ............ 101 Introduction ................................ ................................ ................................ ........................... 101 MaterialsandMethods ................................ ................................ ................................ ......... 102 AnimalsandForages ................................ ................................ ................................ ..... 102 Experiment1 ................................ ................................ ................................ .......... 103 Experiment2 ................................ ................................ ................................ .......... 103 SampleCollection ................................ ................................ ................................ ......... 104 ChemicalAnalyses ................................ ................................ ................................ ........ 105 S tatisticalAnalyses ................................ ................................ ................................ ........ 106 Results ................................ ................................ ................................ ................................ ... 106 Experiment1 ................................ ................................ ................................ ................. 107 PastureHerbageMassandNutritiveValue ................................ ........................... 107 AnimalPerformance ................................ ................................ .............................. 109 Experiment2 ................................ ................................ ................................ ................. 112 PastureHerbageMassandNutritiveValue ................................ ........................... 112 AnimalPerformance ................................ ................................ .............................. 117 Discussion ................................ ................................ ................................ ............................. 117 ForageProductionandNutritiveValue ................................ ................................ ......... 117 AnimalPerformance ................................ ................................ ................................ ...... 122 8 SUMMARY,CONCLUSIONS,ANDRECOMMENDATIONS ................................ ....... 125 APPENDI X A SLIDINGSCALEFORURINECOLLECTIONSFORCHAPTER4 ............................... 133 B CONDENSEDTANNINSMETHODFORCHAPTER4 ................................ .................. 134 PurificationofQuebrachoTannin ................................ ................................ ........................ 134 CondensedTannin(CT)Extraction ................................ ................................ ...................... 135 ExtractableCondensedTanninAnalysis ................................ ................................ .............. 136 BoundCondensedTanninAnalysis ................................ ................................ ...................... 137 Calculations ................................ ................................ ................................ .......................... 137

PAGE 9

9 C PURINEDERIVATIVESMETHODFORCHAPTERS4AND6 ................................ .... 138 ConversionofXanthine,HypoxanthineandUricAcidtoAllantoin ................................ ... 138 Calculations ................................ ................................ ................................ .......................... 139 D SASCODESUSEDFORCHAPTER3 ................................ ................................ .............. 140 E SASCODESUSEDFORCHAPTER4 ................................ ................................ .............. 142 F SASCODESUSEDFORCHAPTER5 ................................ ................................ .............. 144 G SASCODESUSEDFORCHAPTER6 ................................ ................................ .............. 145 H SASCODESUSEDFORCHAPTER7 ................................ ................................ .............. 147 I NETPRESENTVALUECA LCULATIONEXPLAINATIONFORT ABLE 8 2 ............. 151 LISTOFREFERENCES ................................ ................................ ................................ ............. 152 BIOGRAPHICALSKETCH ................................ ................................ ................................ ....... 172

PAGE 10

10 LISTOFTABLES Table page Table4 1.Chemicalcomposition andinvitrotruedigestibility(IVTD)ofhays ........................ 67 Table4 2.Intakeandapparentdigestibility(DMbasis)oflambsfedbahiagrasshay supplementedwithwarm seasonlegumehaysorsoybeanmeal(SBM) ........................... 68 Table4 3.Nitrogenbalance,microbialNsynthesis,apparentlydigestedOM(DOM),and bloodmetabolitesoflambsfedbahiagrasssupplementedwithwarm seasonlegume haysorsoybeanm eal(SBM) ................................ ................................ ............................. 69 Table4 4.RuminalfluidpH,NH 3 NandVFAconcentrationsoflambsfedbahiagrasshay supplementedwithwarm seasonl egumehaysorsoybeanmeal(SBM) ........................... 71 Table5 1.Chemicalcompositionandinvitrotruedigestibilityofforagesbeforewiltingan d ensiling ................................ ................................ ................................ ............................... 81 Table5 2.Haylagechemicalcompos itionandinvitrotruedigestibility ................................ ..... 81 Table5 3.Fermentationcharacteristicsofbahiagrasshaylageandfourwarm seasonlegume haylages ................................ ................................ ................................ .............................. 82 Table5 4.Microbialcountsandaerobicstabilityofbahiagrasshaylageandwarm season legumehaylages ................................ ................................ ................................ ................. 82 Table6 1.Chemicalcompositionandinvitrotruedigestibility(IVTD)ofhaylages .................. 93 Table6 2.Intakeandapparentdigestibility(DMbasis)ofbahiagrasshaylagesupplemented withorwit houtlegumehaylagesorsoybeanmeal(SBM) ................................ ................ 94 Table6 3.Nitrogenbalance,microbialNsynthesis,apparentlydigestedOM(DOM),and bloodmetabolitesoflambsfedbahiagrasshaylagesupplementedwithwarm season legumehaylagesorsoybeanmeal(SBM) ................................ ................................ ......... 95 Table6 4.RuminalfluidpH,NH 3 NandVFAconcentrationsoflambsfedbahiagrass haylagesupplem entedwithwarm seasonlegumehaylagesorsoybeanmeal(SBM) ....... 96 Table7 1.TheperformanceofcowsandcalvesgrazedonTifton9bahiagrasspastureswith orwithoutcowpeaorperennialpeanutcreepareas ................................ ......................... 111 Table7 2.Thep erformanceofcowsandcalvesgrazingArgentinebahiagrasspastureswith orwithoutacreepfeedoracowpeacreepgrazingarea ................................ .................. 118 Table8 1.Costsofproducingperennialpeanut(cv.Florigraze ),annualpeanut(cv. Florida MDR98),cowpea(cv.Ironclay),pigeonpea(cv.Georgiatwo),andsoybean(cv. Pioneer97B52)forage,hay,orhaylageproductionin2006 ................................ ........... 127

PAGE 11

11 Table8 2.Netpresentvaluesummaryforperennialpeanut(cv.Florigraze),annualpeanut (cv.FloridaMDR98),cowpea(cv.Ironclay), pigeonpea(cv.Georgiatwo),and soybean(cv.Pioneer97B52)forage,hay,orhaylageproductionovera20 yrhorizon 128 Table8 3.Foragemanagementcharacteristicsofperennialpeanut(cv.Florigraze),annual peanut(cv. FloridaMDR98),cowpea(cv.Ironclay),pigeonpea(cv.Georgiatwo), andsoybea n(cv.Pioneer97B52) ................................ ................................ .................... 129 TableA 1.Slidingscal eforurinecollections ................................ ................................ ............. 133

PAGE 12

12 LISTOFFIGURES Figure page Figure2 1.Hatch Slack(C 4 )carbonfixationpathwayutilizedbywarm seasongrasses ............ 22 Figure2 2.Cross sectionofaC 3 grassleaf( Poa spp.) ................................ ................................ 23 Figure2 3.Cross sectionofaC 4 grassleaf(Sugarcane( Saccharumofficinarum L.)) ................. 23 Figure2 4.Comparisonofnitrogenmetabolisminruminantsfedlownitrogenintake(A) andhighnitrogen(B)intake ................................ ................................ .............................. 28 Figure3 1.AveragemonthlyrainfallinMarianna,Florida,duringthreeyearsof experimentation ................................ ................................ ................................ .................. 49 Figure3 2.Averagemonthlytemperature(C)inMarianna,Florida,durin gthreeyearsof experimentation ................................ ................................ ................................ .................. 50 Figure3 3. Changesinherbagemass(kgDM/ha)ofcowpea,pigeonpeaandsoybean .............. 51 Figure3 4.Leaf to stemratioofcowpea,pigeonpea,andsoybean ................................ ............. 51 Figure3 5.WholeplantCPandNDFconcentrations(DMbasis)andinvitrotrue digestibility(IVTD)ofcowpea,pigeonpeaandsoybean ................................ .................. 53 Figure3 6.CrudeproteinandNDFconcentrations(DMbasis)andinvitro truedigestibility (IVTD)ofcowpea,pigeonpeaandsoybeanstems ................................ ............................ 54 Figure3 7.CrudeproteinandNDFconcentrations(DMbasis)andinvitrotruedigestibility (IVTD)ofcowpea,pigeonpeaandsoybeanleaves ................................ ........................... 55 Figure7 1.Monthlyaveragetemperature(C)in2007and30 yraverageinMarianna,FL .... 107 Figure7 2.Monthlyaveragerainfall(cm)in2007and30 yraverageinMarianna,FL ........... 107 Figure7 3.ChangesinherbagemassofTifton9bahiagrasspasturesandcowpeaand perennialpeanutcreepareasduringthegrazingperiod ................................ ................... 108 Figure7 4.Changesinleaf to stemratioofcowpeaandperennialpeanutduringthegrazin g period ................................ ................................ ................................ ............................... 109 Figure7 5.ChangesinNDFandCPco ncentrations(DMbasis)andinvitrotrue digestibility(IVTD)ofTifton9bahiagrasspastureandcowpeaandperennialpeanut creepareasduringthegrazingperiod ................................ ................................ .............. 110 Figure7 6.BodyweightofcalvesgrazedonTifton9bahiagrasspastureswithorwithout cowpeaorperennialpeanutcreepareas ................................ ................................ ........... 111

PAGE 13

13 Figure7 7.Plasmaureanit rogen(PUN;mg/dL)concentrationincowsandcalvesgrazedon Tifton9bahiagrasspastureswithorwithoutcowpeaorperennialpeanutcreepareas ... 113 Figure7 8.Plasmaglucose(PGlu;mg/dL)concentrationincowsandcalvesgrazedon Tifton9bahiagrasspastureswithorwithoutcowpeaorperennialpeanut creepareas ... 114 Figure7 9.Changesinherbagema ssofArgentinebahiagrasspasturesandcowpeacreep areasduringthegrazingperiod ................................ ................................ ........................ 115 Figure7 10.Changesinleaf to stemratioofcowpeaduringthegrazingperiod ...................... 115 Figure7 11.ChangesinNDFandCPconcentrations(DMbasis)andinvitrotrue digestibility(IVTD)ofArgentinebahiagrasspastureandcowpeacreepareasduring thegrazingperiod ................................ ................................ ................................ ............ 116 Figure7 12.BodyweightofcalvesgrazedonAr gentinebahiagrasspastureswithorwithout cowpeaorconcentratecreepareas ................................ ................................ ................... 118 Figure7 13.Plasmaureanitrogen(PUN;mg/dL)concentrationincalvesandcowsgrazed onArgentinebahiagrasspastureswithorwithoutcowpeaorconcentratecreepareas ... 119 Figure7 14.Plasmaglucose(PGlu;mg/dL)concentrationincalvesandcowsgrazedon Argentinebahi agrasspastureswithorwithoutcowpeaorconcentratecreepareas ........ 120

PAGE 14

14 LISTOF ABBREVIATIONS ADF Aciddetergentfiber ADG Averagedailygain ADL Aciddetergentlignin B Boron BT Boundtannin BW Bodyweight cfu Colony formingunits CP Crudeprotein CT Condensedtannin DIP Degradableintakeprotein DM Drymatter DOM Digestible organicmatter ExtCT Extractablecondensedtannin ISD Insitudegradation IVDMD Invitrodrymatterdigestibility IVOMD Invitroorganicmatterdisappearance IVTD Invitrotruedigestibility K 2 O Potassiumoxide ME Metabolizableenergy MP Microbialprotei n N Nitrogen NDF Neutraldetergentfiber NH 3 N Ammonia nitrogen NSC Non structuralcarbohydrate

PAGE 15

15 OM Organicmatter OMTD Organicmattertrulydigested P Phosphorus P 2 O 5 Diphosphoruspentoxide PD Purinederivatives PDF Potentiallydegradablefiber PGlu Plas maglucose PUN Plasmaureanitrogen R1 Stageatwhichthefirstflowerappearsonsoybean( Glycinemax (L.) Merr.) R6 Stageatwhichsoybeanpodsatthefirst4nodeshavefull sizeseeds R7 Stageatwhichonesoybeanpodismature RDP Rumen degradablepr otein RUP Rumen undegradableprotein S Sulfur SBM Soybeanmeal TDN Totaldigestiblenutrients VFA Volatilefattyacids WAP Weeksafterplanting WSC Water solublecarbohydrates

PAGE 16

16 AbstractofDissertationPresentedtotheGraduateSchool oftheUniversityofFlorida inPartialFulfillmentofthe RequirementsfortheDegreeofDoctorofPhilosophy IMPROVINGTHEPRODUCTIVITYOFLIVESTOCKWITHWARM SEASONLEGUMES By Jam ieLeeFoster May2008 Chair:AdegbolaAdesogan Cochair:JeffreyCarter MajorDepartment:AnimalSciences Thefirstexperiment aimedto determinetheherbagemassproductionandnutritivevalue ofpigeonpea( Cajanuscajan (L.)Millsp.cv.Georgia two ), cowpea( Vignaunguiculata (L.) Walp. cv. Ironclay) andsoybean( Glycinemax (L.)Merr.cv. Pioneer97B52)in N orthFlorida. Whenharvestedatrespectivematuritystagesthatmaximizednutritivevalueandherbagemass, soybeanandpigeonpeaproducedgre ater( P <0.01)herbagemassthancowpea,whereastheCP concentrationsandinvitrotruedigestibility(IVTD)ofcowpeaandsoybeanweregreater( P < 0.05).Anotherexperimentexaminedthenutritivevalue,fermentationcharacteristics,and aerobicstabil ityofcowpea,pigeonpea,annual( Arachishypogaea L. cv. FloridaMDR98)and perennial( Arachisglabrata Benth.cv.Florigraze)peanut,andbahiagrass( Paspalumnotatum Flgge)haylages. P erennialandannualpeanutandcowpeahaylageshadnormalpHvalue sbut otherhaylageshadhighvalues.Yeastandmoldcountswerelowandaerobicstabilitywasat least84hinallhaylages.PigeonpeaandbahiagrasshaylageshadlowerIVTD( P <0.05)than theothers.Inadditionalexperiments,haysandhaylagesmade fromtheselegumeswere supplemented(50%ofdietDM)tobahiagrasshayorhaylageinlambdiets.Perennialpeanut andannualpeanuthay s orhaylage s werethebestsupplementsbecausetheyresultedinthe greatest( P <0.05)intakes greaterdigestionof DMandOM andgreaterNretentionthanthe

PAGE 17

17 controldiet.Soybeanhayandcowpeahayorhaylagewerealsopromisingsupplementsbecause theyincreased( P <0.05)DMandOMintakeandNretentionversus thecontroldiet .Pigeonpea hayorhaylagedidnoti mprove( P <0.05)intakeordigestionofDMorOM.Afinalexperiment examinedeffectsofcreepfeedingcowpea,concentrate,orperennialpeanuttocow calfpairson bahiagrasspasture.Calvescreepgrazingcowpeaandthosecreep fedtheconcentratetend ed( P <0.10)tohavegreaterADG.Supplementingwitheachwarm seasonlegume,exceptpigeonpea, improvedtheperformanceofruminantsfedbasalbahiagrassdiets.Annualandperennialpeanut werethemostpromisingstoredlegumes,andcowpeashowedmore promisethanperennial peanutwhencreep grazed.

PAGE 18

18 CHAPTER1 INTRODUCTION In2006,theFloridacow calfindustryhadcashreceiptsof$330millionandover1.7 millionheadofbeefcattle(NASS,2006).CalvesborninFloridaduring2006totaled910,000 headand78%oftheseweresold(FASS,2007).Beefc attlearethereforeanimportantpartof Floridaseconomy.Theyconvertmostofthe1.4millionhectaresofplantedpastureandrange inFlorida(NASS,2002),whichmayotherwisebewasted,intofeedercattle,ahighquality, desirableproduct. Ideally ,calvesshouldweighabout227kgatthepointofsale,whichisusuallyatweaning (6to9moofage),butthistargetrequiresaveragedailygainsofatleast0.91kgBW/d.These weightsimpactproducerprofitandarecloselycorrelatedwithcalfsurvi valandgrowthafter shipment(Marshall,1994).MostofthebeefcattleinFloridaaregrazedonbahiagrass ( Paspalumnotatum Flgge)pasturesbecausebahiagrassisadaptedtothedifferentsoilsand environmentsinFlorida,itismoderatelyproductivewi thlittlefertilization,anditistolerantof heavygrazing(Chambliss,2002).However,thelowqualityofbahiagrassimpliesthatoptimal calfgainsonbahiagrasspasturealonearelimitedtoabout0.65kgBW/donbahiagrasspasture andmilkfromtheco w(Hammondetal.,1997)orabout0.40kgBW/dforofweanedsteers grazingonlybahiagrass(Utleyetal.,1974)orabout.Thereforesupplementationwithvarious grainsandorbyproductsisnecessarytoachievethedesiredmarketweightsatweaning.Most of thegrainsareimportedintothestateatsignificantcosts,whicharelikelytoincreaseduetothe escalatingpriceoffuel.Inaddition,seasonalityofproductionandvariabilityinqualityof byproductslimitstheiruseincattlerations.Usingc oncentrates,byproductsandNfertilizers usuallyresultsinthenetimportationofnutrientsintofarms,whichisundesirablefroman environmentalstandpoint.

PAGE 19

19 Leguminousplantscanbeusedinplaceofsupplementstooptimizethegrowthofcalves. Leg umesaremoredigestiblethanwarm seasongrassesbecausetheycontaingreaterCPand non structuralcarbohydrate(NSC)concentrations(Balletal.,2002).Nitrogenfixationby Rhizobium and Bradyrhizobium bacteriaassociatedwithlegumestypicallyreduce stheneedfor Nfertilizersonfarmsthatgrowlegumes.RecentescalationsinthepriceofNfertilizerhave affectedtheprofitabilityofbeefproduction,andcostswilllikelycontinuetoincreaseduetothe requirementfornaturalgasinmanufacturing anhydrousammoniafertilizer(Funderburg,2005). Whenlegumesaresupplementedtosheepandcattleconsumingbahiagrassdiets,DM intakeincreasesleadingtoincreasedgrowth.Therefore,leguminousforagessuchasalfalfa ( Medicagosativa L.)andclove rs( Trifolium spp.)arenowintegralcomponentsofcattlerations intemperateenvironments.Sincethe1960s,therehasbeenatremendousamountofresearchon warm seasonlegumesinAustralia,Africa,AsiaandpartsofLatinAmerica(tMannetje,1997). H owever,relativelylittleisknownabouttheirpotentialusetomaximizetheproductivityof cattleinthesoutheasternUnitedStates.Warm seasonlegumesadaptedtoFloridaproducehigh DMyields(e.g.,peanutvarietiesproduceabout1,700kgDM/haperh arvestafter6to8wk regrowthata8 cmstubbleheight),andmaintaintheirCPconcentrationthroughthegrowing seasonwithlittledecreaseindigestibility(Buloetal.,1994;Leepetal.,2002).The2warm seasonlegumesthathavereceivedmostatten tioninFloridaareperennialorrhizomapeanut ( Arachisglabrata Benth.)andaeschynomene( Aeschynomeneamericana L.).WhenHolstein heifersgrazedpurestandsoftheFlorigrazecultivarofperennialpeanut,theygained0.6kg BW/d,andthepasturepersi stedandprovidedadequateforagewith16%CPthroughOctoberin Florida(HernndezGarayetal.,2004).Romosinuanocalvescreep grazedonperennialpeanut pasturesgained0.2kgBW/dgreaterthancalvesnothavingaccesstocreepgrazing(Williamset

PAGE 20

20 al .,2004).However,establishmentofperennialpeanutisprotracted(upto3yr)andrisky withoutirrigation.Aeschynomeneisadaptedtomoist,flatwoodareas,consequentlyitismore commonlyfoundinsouthernFlorida.Therefore,researchthatelucidat estheeffectofusing unexploited,easilyestablishedwarm seasonlegumesthatwillgrowthroughoutthestateto enhancethegrowthofbeefcalvesisneeded. Thehypothesisofthiscollectionofresearch projectswasthatlikeperennialpeanut, seededwa rm seasonlegumescanbeusedtoincrease nutrientstatusandutilization,andweightgainincattleorsheepfedbasalbahiagrassdiets.

PAGE 21

21 CHAPTER2 LITERATUREREVIEW Warm SeasonGrassPhotosynthesis Physiology Warm seasongrassesproliferateinsubtropicalandtropicalenvironmentsbecauseoftheir specializedphotosyntheticcarboncycle,theHatch SlackorC 4 pathway(TaizandZeiger,2002) Incontrast,cool seasongrassesandmostlegumesutilizetheC 3 ,orCalvinphotosyntheticcycle. ThefirststepofC 3 photosynthesisiscatalyzedwithribulose 1,5 bisphosphate carboxylase/oxygenase(rubisco)(TaizandZeiger,2002).Carboxylationo fribulose bisphosphateiscatalyzedinthechloroplastswithinthemesophyllcells.Becausetheenzyme rubiscocanbindtobothoxygenandcarbondioxide,thereiscompetitionbetweenthetwo atmosphericgasesforbindingsitesontheenzyme(TaizandZe iger,2002).Ifcarbondioxideis boundtorubisco,photosynthesisproceedsbutifoxygenisboundtorubiscophotorespiration occurs.PhotorespirationwastesenergybyremovingcarbonmoleculesfromtheCalvincycle, therebydecreasingtheefficiencyof carbonfixationby40%(TaizandZeiger,2002). PlantsclassifiedasC 4 utilizetheHatch Slackphotosyntheticcarboncyclepriorto carboxylationofribulosebisphosphate(Figure2 1).Twotypesofcellshavelargeamountsof chloroplastinC 4 plants, themesophyllandthebundlesheathcells(TaizandZeiger,2002).The Hatch Slackcycleconcentratescarbondioxidebyfixingittophosphoenolpyruvatecarboxylase inthemesophyllcellcytoplasm(HatchandSlack,1966).Several4 carboncompoundsare produced,andtheseorganiccompoundsaretransportedtothebundlesheathcellswhere decarboxylationoccursandcarbondioxideisreleased(HatchandSlack,1966).Inthe chloroplastsofthebundlesheathcells,carbondioxidebindstorubiscoandenter stheCalvin Cycle(HatchandSlack,1966).Becausecarbondioxideisfixedtwice,theHatch Slackpathway

PAGE 22

22 requiresmoreenergy(TaizandZeiger,2002).However,theconcentrationofcarbondioxideat rubiscobindingsitesinC 4 plantslimitsphotorespir ation.InC 3 plantsasthetemperature increases,rubiscoincreasesoxygenationcausingphotosynthesistobecomelessefficient(Kuand Edwards,1978).TheC 4 pathwayismoreenergeticallyefficientinwarmclimates(Taizand Zeiger,2002). Anato my ChloroplastsarelocatedinthemesophyllcellsinC 3 plantsandmesophyllcellsare dispersedthroughouttheleaf(Figure2 2).InC 3 plants,bundlesheathcellssurroundingthe vascularbundlesarenotalwaysincloseproximitytomesophyllcells.M esophyllcellsattachthe epidermistolargevascularbundlesinC 3 plants(Wilsonetal.,1989).Thearrangementof vascularbundlesandbundlesheathcellsisloosewithintercellularspaceandair. Figure2 1.Hatch Slack(C 4 )carbonfixationpathwayutilizedbywarm seasongrasses AdaptedfromTaizandZeiger(2002)

PAGE 23

23 Thespecializedphoto syntheticpathwayofC 4 plantsisassociatedwithspecialized anatomy(Figure2 3).MesophyllcellsofC 4 plantsarelocatednearbundlesheathcellsbecause ofthecooperationbetweencellsduringtheHatch Slackcarboncycle(TaizandZeiger,2002). Th esecellsarearrangedinaKranzorwreathstructure.Thebundlesheathcellssurroundthe vascularbundle.Plasmodesmatajointhemesophyllandbundlesheathcellsfortransferof compounds(TaizandZeiger,2002).IncontrasttoC 3 plants,thereisl ittlespacebetweenthe cellsintheKranzanatomy.AgirderstructureattachesthexylemoftheC 4 planttothe epidermisoftheleaf(Wilsonetal.,1989).Becausecarbondioxideisconcentratedbefore bindingwithrubisco,C 4 plantsneedlessrubisco thanC 3 plantsforthesamerateof Figure2 2.Cross sectionofaC 3 grassleaf( Poa spp.) AdaptedfromTaizandZeiger(2002) VascularBundle Epidermis Mesophyl lCells MesophyllCells GirderStructure KranzStructure Epidermis BundleSheathCells VascularBundle AdaptedfromTaizandZeiger(2002) Figure2 3.Cross sectionofaC 4 grassleaf(Sugarcane( Saccharumofficinarum L. ))

PAGE 24

24 photosynthesis(vonCaemmerer,2000).Consequently,N useefficiencyisgreaterinC 4 plants thaninC 3 plantsbutthisdecreasestheNconcentrationinC 4 plantsrelativetoC 3 plants. DigestioninRuminants TheRumina ntandWarm SeasonGrasses TheanatomicalandphysiologicaldifferencesbetweenC 3 andC 4 plantsaffecttheir nutritivevalueforruminantanimals.Ruminantshaveanatomicaladaptations,includingthe rumen,whichallowdigestionandutilizationoffibrou sforages(VanSoest,1994).Therumen containsmicrobesincludingbacteria,protozoaandfungi,whichproduceenzymestodigest structuralcarbohydratesfortheirgrowth(VanSoest,1994). Specializedmicrobes(cellulolytics) intherumenutilizecellul asetobreakthebeta glucosidaselinkagesincellulosetorelease glucoseforenergy(rskov,1992). Mammalscannotproducetheseenzymes,thereforewithout associationwithmicrobesruminantswouldnotbeabletosubsistoncelluloseandotherfiber com ponentsofforage(VanSoest,1994). Themesophyllandphloemtissuesofgrassleavesaredegradedeasilybyruminalfibrolytic microbeswhiletheepidermisandbundlesheathtissuesareslowlydegraded,butthe sclerenchyma(girderstructure)andlignif iedvasculartissuearenotdegradedintherumen(Akin andBurdick,1975).Thereisagreaterproportionofslowlydegradableandundegradabletissue inC 4 grassesthaninC 3 grassesbecauseofthelowernumberofmesophyllcells,greater proportionoft hick walledbundlesheathcells,andlimitedintracellularspacewithintheKranz structure,andthepresenceofagirderstructureinC 4 plants(AkinandBurdick,1975;Wilsonet al.,1989;Floresetal.,1993).Theseanatomicalfeatureslimitmicrobial degradationoffiberin C 4 plants.

PAGE 25

25 Intake,DegradationandPassage Inmonogastricmammals,intakeisdrivenbydeficiencyofenergyorproteinamongother factors,butinruminantanimalsintakeisalsohinderedbythephysicallimitationsofrumensize an drateoffeedpassage(VanSoest,1994).Foragemustbereducedtoacriticalsizebefore particlespassfromtherumentotheomasumthroughthereticulo omasalsphincter(Troelsenand Campbell,1968;Poppietal.,1980).Rateofparticlesizereductio nisthemainfactorlimiting therateofpassagefromtherumen(BalchandCampling,1962;Ulyattetal.,1986).Therateof passageisslowerwhenruminantsarefedC 4 grassesthanwhentheyconsumeC 3 grassesbecause oftheincreasedstructuraltissue intheformer(Floresetal.,1993).Whensteerswerefedeither bermudagrass( Cynodondactylon (L.)Pers.)ororchardgrass( Dactylisglomerata L.)hays,total DMintakewasgreaterinsteersfedorchardgrasshay(Lagasseetal.,1990).BeingaC 4 grass, bermudagrasshadgreaterstructuraltissue(71%NDF)thanorchardgrass(64%NDF),whichisa C 3 grass(AkinandBurdick,1975;Wilsonetal.,1989).Theorchardgrasshayhadafasterrate ofparticlesizereductionthroughmastication,whichincreasedmi crobialaccesstopotentially degradablefiber(Wilsonetal.,1989).Smallerparticlesrequirelesstimeformicrobial attachmentanddegradationthanlargerparticles,andallowgreateraccessofmicrobestofiber (Ellisetal.,2005)andcellcontents. Theincreasedrateofparticlesizereductioninorchardgrass allowedforafasterrateofpassagewhichprovidedspaceintherumenforincreasedintake. Intakeisthemostimportantfactoraffectingforagequality(VanSoest,1994;Colemanand Moore, 2003);therefore,factorsthatdecreaseintakebyreducingrateofpassageareofparticular interesttoruminantnutritionists. RumenMicrobialGrowth Tomaximizemicrobialgrowthanddegradationofdigesta,requirementsoftheruminal microbialpopulat ionforprotein,energy,andothernutrientsmustbemet.Maximizingmicrobial

PAGE 26

26 growthandactivityincreasestherateofdegradationoffeeds,whichinturnincreasesrateof passageandintake. ThereisastrongcorrelationbetweendietaryCPconcentrat ionandruminal NH 3 Nconcentration(SatterandRoffler,1975),andithaslongbeenunderstoodthatinorderto maximizeruminalmicrobialgrowthandmicrobialproteinproduction,aminimumof50mg/Lof NH 3 Ninruminalfluidisnecessary(SatterandSly ter,1974).However,theconcentrationof NH 3 Nrequiredtomaximizefiberdegradationisdependentupontheenergysourceandamount (rskov,1992).AsdigestibilityortheMEvalueoffeedsincrease,theNrequirementofthe microbesincreases(rskov, 1992).IfdietaryCPisdeficient,activityoffibrolyticmicrobesin therumenisdecreasedbecausetheirnutritionalneedsarenotmet(rskov,1992). Thiswas verifiedinastudythatsupplementeddegradableintakeprotein(DIP)intheformofcasein to cattlefedalowprotein(1.9%CP)andhighroughage(77%NDF;50%ADF)diet(Ksteretal., 1996).AstheconcentrationofDIPincreased,digestibilityandtherateofpassageincreased (Ksteretal.,1996).Slowerratesofpassageincreasetheamo untofdietaryenergyutilizedfor maintenancebyruminalbacteria,decreasingmicrobialefficiency(OwensandGoetsch,1986). InthestudyofKsteretal.(1996),microbialefficiencywasincreasedwhenmicrobialfiber degradationwasnolongerlimited byinadequateprotein,consequentlyparticulaterateof passageincreased. Whenruminantsarefedlowqualityforageswithlowrumen degradableprotein(RDP) concentrationsandslowfiberdegradationrateslikeC 4 grasses,microbialgrowthrateisslowa nd rateofpassagedecreases(OwensandGoetsch,1988).Microbialefficiencyisconsideredlow whenitfallsbelow20gmicrobial N/kgdigestibleOMintakeandhighwhengreaterthan35g microbial N/kgdigestibleOMintake(Dewhurstetal.,2000).Cattl egrazingcool seasongrasses havemicrobialefficiencyrangingfrom25to30gmicrobial N/kgdigestibleOMintake(Dove

PAGE 27

27 andMilne,1994;Elizaldeetal.,1998),butfeedingwarm seasongrassesoftenresultsinlow efficiency(<15gmicrobial N/kgdigest ibleOMintake;Brakeetal.,1989;Mupwangaetal., 2000b;Abreuetal.,2004). RuminantversusMicrobialNutrientRequirements Pre gastricfermentationproductsandruminallyundegradeddigestamustmeetthe ruminantsnutrientrequirements(VanSoest, 1994).IftheruminantisfedsufficientdietaryCP tomeetitsruminalmicrobialrequirements,theaminoacidsandproteinsenteringthesmall intestineintheformofmicrobesshouldbeadequatetomeettheruminantsproteinrequirements (Tamminga,197 9;VanSoest,1994).Postruminalmicrobialdegradationisfacilitatedby lysozymec,anenzymethatbreaksdownthepeptidoglycanlayerinbacterialcellwalls.The enzymeis1,000to3,000timesmoreactiveinthegastrointestinaltractofruminantani malsthan innon ruminants(Dobsonetal.,1984)toallowdigestionandutilizationofnutrientsfrom ruminalmicrobes. Intherumen,microbesdigestproteinsintoNH 3 Nfortheirgrowth.WhenDIPsupplyis high,NH 3 Nthatisnotutilizedformicrobial growthflowsoutoftherumenorisabsorbed throughtherumenwall(Figure2 4;VanSoest,1994).Intheliver,absorbedNH 3 Nis convertedtoureaanditisrecycledthroughthebloodandsalivabacktotherumen( rskov, 1992; VanSoest,1994).When dietaryNisfedinexcess,moreruminallyundegradeddietary andmicrobialNentersthesmallintestineandurinaryureaconcentrationisalsoincreased.In contrast,wheninsufficientNisfed,absorptionofNH 3 Nthroughtherumenwalliseliminated an dtheamountofmicrobialanddietaryNenteringthesmallintestineisreducedasisurinary ureaexcretion.RecyclingofNasureaisenhancedundersuchconditions,andthisallows microbialgrowthevenwhendietaryNsupplyislow.Lactatingandgrow ingcattlerequire greaterproteinthanruminalmicrobescanprovide( rskov,1992; VanSoest,1994);

PAGE 28

28 consequently,dietsofsuchanimalsneedtocontainadequaterumen undegradableprotein (RUP). Becauserumenmicrobesprimarilyrequireenergyforgrowt h,energyisthefirstlimiting nutrientformostruminants.Theenergyprovidedbywarm seasongrassesistypically inadequatetomeettherequirementsofruminantsbecausesomeoftheanatomicalfeaturesof suchgrasseslimitthefiberdegradabilitythe rebyreducingenergysupply(Floresetal.,1993; Nevins,1993;Wilson,1994). Figure2 4.Comparisonofnitrogenmetabolisminruminantsfedlownitrogenintake(A)and highnitrogen(B)intake Adapte dfromVanSoest(1994)

PAGE 29

29 Bahiagrass AgronomicCharacteristics Inareaswithhighra infall,plantedforagesareutilizedforlivestockgrazingandhay production.Oneofthepreferredwarm seasonperennialgrassforthispurposeinthe southeasternUnitedStatesisbahiagrass( Paspalumnotatum Flgge;BarnesandNelson,2003), whichisn ativetoSouthAmerica,andhencelesscold tolerantthanwarm seasonperennial grassesnativetotheGreatPlainsregionoftheUnitedStates(RedfearnandNelson,2003). BahiagrassisbestsuitedforproductiononsandysoilswithapHfrom5.5to6.5. Whengrown underdry,lowfertilityconditions,bahiagrassismorepersistentandhigheryieldingthan comparativewarm seasongrassessuchasbermudagrassanddallisgrass( Paspalumdilatatum Poir.;Redmon,2002;RedfearnandNelson,2003).Fertilization isrequiredforadequateDM production;however,bahiagrassmaynotrespondtoincreasingNfertilizerabove112kg/ha (Johnsonetal.,2001;Redmon,2002).Bahiagrassisefficientatphotosynthesisunderhighlight andtemperaturebecauseitutilizesth eC 4 photosyntheticpathway. Pasturesofbahiagrasscanbecontinuouslystockedduringthesummergrowingseason becauseoftheirabilitytowithstanddefoliationtostubbleheightsof4to8cm( Ortega S.etal., 1992 ;RedfearnandNelson,2003).Toler anceofcontinuousstockingisachievedbythereserves theplantstoreswithinrhizomesthatarenotgrazed,whichallowforrapidregrowthfollowing defoliation,andbymaintenanceofleafareaclosetothesoilsurface.Thepersistenceof bahiagrassis alsoaidedbyitstoleranceoftreadingbylivestockandtheabilityoftheseedto passthroughtheanimalsdigestivetractundigestedandgerminateafterpassage(Balletal., 2002).Bahiagrassisavailableearlierinthespringandlaterintheautu mnmonthsthan bermudagrass,andtheTifton9cultivarprovidesalongergrazingseasonthanothercultivars (Gatesetal.,1999;RedfearnandNelson,2003;Redmon,2002).Bahiagrassisdormantfrom

PAGE 30

30 OctobertoAprildueinparttodaylightsensitivity,co nsequentlythequantityofbahiagrass herbageavailableforgrazing decreasesinthewinter(Blountetal.,2001;Gatesetal.,2001). NutritiveValue AsummaryofseveralstudiesonbeefsteerperformanceonpasturesinthesouthernUnited Statesindica testhatsteerADGisapproximately0.40kg,andgainperhaisapproximately250 kgwhenbahiagrassisgrazedduringa4to5mograzingseason(Utleyetal.,1974).Insucha system,ADGof0.68kgfortheseasonisoftenadesiredgoalofmoderateinpu tproduction systems,andtoachievesuchgainsdietscontaining12%CPand65 68%DMdigestibilityare requiredbybeefcattle(NRC,2000).Thenutritivevalueofbahiagrassvarieswithmaturityand durationoftheregrowthperiodaftercuttingorgrazin g,butaveragevaluesof8.3%CP,50% DMdigestibility,and44.2%ADFaretypical(Mooreetal.,1991;Redmon,2002).These nutrientconcentrationsaresufficienttomeettherequirementsofmaturecattle,buttheyare insufficientforweaned,growingani mals(Redmon,2002).AccordingtoNRC(2000), bahiagrasspasturesprovide54%TDN,1.11Mcal/kgnetenergyformaintenance,and0.55 Mcal/kgnetenergyforgrowth.Aweaned,250 kgAngussteerrequires4.84Mcal/dfor maintenanceandanadditional3.21M cal/dtogain1.0kg/d(NRC,2000).Thiswouldrequirea DMintakeofbahiagrassinexcessof10kg/dDM,butpredictedestimatesofbahiagrassintake areonlyabout8kg/d(NRC,2000)becausethehighNDFandADFconcentrationslimitintake anddigestion Averagedailygainoflivestockislimitedonwarm seasongrassesduetotheirlow digestibilityratherthantheamountofforageavailableforconsumption(Dubleetal.,1971).The qualityofbahiagrassdeclineslateinthegrowingseasonduringpeak production(Johnsonetal., 2001).ThedecreaseinCPconcentrationandincreaseinindigestiblefiberconcentrationreduces theforagequalityforthegrazinganimal(Buloetal.,1994).Whenbahiagrasspasturesare

PAGE 31

31 fertilizedwithN,theCPconcentrat ionofincreases,butthisincreasedoesnottypically compensateforthedecreaseinCPconcentrationthroughthegrowingseason(Johnsonetal., 2001).Therefore,theCPconcentrationandenergyprovidedbybahiagrassisinadequatefor growingorlactat ingcattle,particularlylateinthegrazingseasonwhentheforagematures (Mooreetal.,1991;Johnsonetal.,2001). LegumeSupplementation EffectsonIntakeandDigestibility LegumesutilizeaC 3 pathwayforcarbonfixation.Consequently,theyconta inless celluloseandhemicellulosethanwarm seasongrassesandaremoredigestible(Frame,2005). However,legumeshaveagreaterligninconcentrationthangrasses(VanSoest,1994;Frame 2005)duetohighlylignifiedstems(Wilson,1994).Ligninlimit sthepotentialdegradationof fiberbecauseitformsunhydrolyzablelinkageswiththecellwall(AkinandBurdick,1975; Chandleretal.,1980).Despitehavinggreaterligninconcentrationsthangrasses,legumeshave greaterratesofruminalparticlesiz ereductionthangrasses(Moseley,1981;KellyandSinclair, 1989).Thisispartlybecauseleavesofmostgrasseshaveparallelvenation,butthoseoflegumes havereticulatevenation(Wilmanetal.,1996),whichallowsforeasierbreakageoflegume leave sintoisolatedvascularbundlesduringmastication(Wilson,1994).Greaterisolationof vascularbundlesinlegumesincreasessurfaceareaforattachmentoffibrolyticmicrobes (Wilson,1994).Consequently,increasedDMintakeanddigestibilityarecomm onlyreported whenwarm seasongrassesaresupplementedwithlegumes(NdlovuandBuchanan Smith,1985; SaidandTolera,1993;Goetschetal.,1997;Wederetal.,1999;Mupwangaetal.,2000a;b). LegumeshavegreaterCPconcentrationsthangrasses(Saidan dTolera,1993;Frame, 2005)asaresultofasymbioticrelationshipwith Rhizobium and Bradyrhizobium bacteria,which fixandprovideatmosphericNtotheplant(Franssenetal.,1992;TaizandZeiger,2002).In

PAGE 32

32 exchange,thelegumeprovidesthebacteria withenergy(Franssenetal.,1992;TaizandZeiger, 2002).Legumesalsosupplygreateramountsofmineralsandvitaminstoruminalmicrobesthan grasses(SaidandTolera,1993;PoppiandNorton,1995).Duetothegreaterconcentrationsof CP,potential lydegradablefiberandmineralsinlegumes,theefficiencyofmicrobialN productionisoftengreaterwhenruminantgrassdietsaresupplementedwithlegumes (Tjandraatmadjaetal.,1993;Leeetal.,2003a),ifthecarbohydratesupplytomicrobesisnot l imitingtotheirgrowth(Dewhurstetal.,2000;HallandHerejk,2001;Leeetal.,2003b). Dietaryintakeoflegumesalsostimulatesruminalmicrobialgrowthandthusincreasesthesupply anddigestionofmicrobesinthesmallintestine(Mupwangaetal., 2000a). MostoftheproteininforagelegumesisintheformofRDP,andlegumeRDPmaybe convertedtoNH 3 Nintherumenmorerapidlythanitisutilizedformicrobialproteinsynthesis (Broderick,1995).TopreventlossofthisexcessNH 3 Nfromthe rumen,whichcandecrease theefficiencyofNutilization(Figure2 4),legumesareusuallyfedwithgrassesorwhole plant cereals.TheenergysupplyfromthegrassesincreasestheutilizationofNH 3 Nformicrobial proteinsynthesis.Whenredclover( Tr ifoliumpratense L.)silagewasincludedat30,50and 70%(DMbasis)inabasalperennialryegrass( Loliumperenne L.)silagediet,productionof microbialN(gN/kgorganicmattertrulydigested(OMTD))was8%moreefficientthanwhen grasssilagewas fedalone(Merryetal.,2006).Merryetal.(2006)attributedtheimproved efficiencytotheincreaseintheamountofdigestibleorganicmatterintake,theincreasedparticle sizereduction,thefasterratesofpassage,andadequateenergysupplytothe microbes.Adding whiteclover( Trifoliumrepens L.)silagetocornsilagedietsalsoimprovedNutilizationand consequentlyincreasedbodyweightgainandmilkproductionincattle(Auldistetal.,1999).

PAGE 33

33 ImprovedN useefficiencytypicallyimprovesth eproductivityandprofitabilityoflivestock production. CondensedTannins Ingeneral,condensedtanninsarepresentinlegumesingreateramountsthaningrasses (Reed,1995).Condensedtanninsprecipitateproteinintherumensothatitisunavailable to ruminalmicrobes,buttheacidicconditionsintheabomasumcanbreaksomecondensedtannin proteinlinkagesandallowtheproteintobeavailablefordigestioninthesmallintestine (Waghornetal.,1987;BroderickandAlbrecht,1997;McMahonetal., 2000).Consequently, lowconcentrationsofcondensedtanninmayimproveproteinutilizationbyruminantlivestock becauseofincreasedrumen undegradableprotein(RUP)supplytothesmallintestinewhereitis usedmoreefficiently(Waghornetal.,1987; BroderickandAlbrecht,1997;McMahonetal., 2000).Theoptimalcondensedtanninconcentrationtoincreaseproteinsupplydirectlytothe ruminantis2to4%ofDM(Minetal.,2003;2005).Concentrationsgreaterthan6%ofDM negativelyaffectforageu tilizationbyinhibitingmicrobialdigestionofcellwallsleadingto reducedintakeandpooranimalperformance(Waghornetal.,1994).Highconcentrationsof condensedtanninsiningestedforagesalsoreducetheincidenceofbloat(McMahonetal.,2000) andhelminthinfestation(Butleretal.,2000;Hoskinsetal.,2000).However,thereisno standardizedmethodforanalyzingcondensedtannins.Thediversityofcondensedtannins complicatestheiranalysisanduseofdifferentstandardsamonglaboratori esmakesitdifficultto compareresults.Thesefactorsdemonstratetheneedforastandardmethodofcondensedtannin analysis. TropicallegumesareC 3 plantsthataremoreadaptedtowarmerclimatesthantheircool seasonrelatives.Sometropicalleg umesareknowntohavegreaterligninandcondensedtannin concentrationsthancool seasonlegumes(Waghornetal.,1987;VanSoest,1994;Barahonaet

PAGE 34

34 al.,1997),butmostdonot.Examplesoftropicallegumeswithhighcondensedtannin concentrationsincl udevelvetbundleflower( Desmanthusvelutinus Scheele ), tropicalneptunia ( Neptuniapubescens Benth.), Lespedeza spp.,andsomespeciesinthe Leucaenagenus ,whereas otherslike Acaciaangustissima (Mill.)Kuntzevar. hirta Centrosemamacrocarpum Benth ., Desmodium ovalifolium (Prain)Wall.,cowpea( Vignaunguiculata (L.)Walp. ) ,pigeonpea ( Cajanuscajan (L.)Millsp.),andperennialpeanut( Arachisglabrata Benth.)havelow condensedtanninconcentrations(Romeroetal.,1987;BroderickandAlbrecht,199 7;Baloyiet al.,2001;Carullaetal.,2001;Alexanderetal.,2007;Fosteretal.,2007). Warm SeasonLegumesasLivestockFeeds Legumesarealternativeproteinsourcestocommercialsupplementsinruminantrations andinter seededgrass legumepastures mayextendthegrazingseasonandincreasenutrient supplytograzinglivestocktherebydecreasingfeedcosts(Leepetal.,2002;Muir,2002).Grass legumepasturesalsosupplymoreconsistentDMyieldsthroughthegrazingseasonthangrass alonebutthey aredifficulttoachieveandmaintain(Leepetal.,2002).Bahiagrass legume standsaredifficulttomaintainbecausebahiagrassproducesrhizomesanddevelopsadensesod, whichdominatesweedsandinter seededlegumes(RedfearnandNelson,2003).Comp etitionfor mineralsandwateraffectstheviabilityofsuchmixtures,butcompetitionforlighthasagreater effectinmanycases(Leepetal.,2002).TheC 4 photosyntheticpathwayofwarm season perennialgrassescontrastswiththeC 3 photosyntheticpa thwayofmostlegumes(Sageetal., 1999).PlantswiththeC 4 pathwaydonotbecomelightsaturatedunderthehighheatandlight environmentsofthetropicsandsubtropics(Sageetal.,1999).Rather,theycontinueto photosynthesizeandoutproducethe irC 3 counterparts,whichloseenergyinsuchenvironments throughwastefulphotorespiration.Therefore,C 4 grassesoftendominatetheinter seededC 3

PAGE 35

35 legumesinthesoutheasternUnitedStatesandsimilartropicalandsubtropicalenvironments (Sageetal. ,1999). Pasturesaremoreidealsourcesofnutrientsthanstoredforagesbecausetheyallowanimals toselectleavesandyoungplantparts(Arnold,1987)andbecausenutrientsareoftenlostwhen foragesarestoredashayorsilage(WylieandSchaller, 1939).However,fewlegumespecies persistunderthefrequent,closedefoliationandtreadingassociatedwithunmanagedorpoorly managedgrazing,thereforestorageoflegumesisoftennecessary.Storedlegumesareusually producedasmonoculturestoavo idcompetitionwithgrasses.Alfalfa( Medicagosativa L.)is knownasthequeenofforagesand8.5millionhaweregrownforhayproductionintheUnited Statesin2007(NASS,2007).Alfalfaisanimportantlegumeproteinsupplement,butitdoesnot pers istinthesouthernUnitedStatesbecauseofacid,infertilesoils,diseases,insectsand nematodesassociatedwiththehumidclimate(Prineetal.,1981).Thereareveryfewwarm seasonperenniallegumesinthesoutheastduetothelengthandhightemper aturesofthesummer (Leepetal.,2002;BarnesandNelson,2003).Perennialpeanutisonelegumeadaptedtothis environment. PerennialPeanut PerennialpeanutiswelladaptedtothesoutheastcoastoftheUnitedStates.Over54,360 haofforagepeanut isgrowninSouthernGeorgiaandNorthernFlorida,mostlyasperennial peanut(KalmbacherandKretschmer,2002;SollenbergerandCollins,2003).Perennialpeanut toleratesdroughtandslightlyacidic,lowfertilitysandysoils( Frenchetal.,2006 ).Cur rentuses includehayproduction(6,725to13,450kgDM/hafrom3cuttings/yr5to8wkapart)and pastureandthisspeciesisoneofthegreaterDMproducersofcommonwarm seasonperennial legumes(Buloetal.,1994;Jones,2001;SollenbergerandCollins ,2003).Commonly,itis vegetativelyplantedat100to200bushels/haanddiskedorsprigplantedat3cmdepthintoa

PAGE 36

36 fullyprepared,weed freeseedbedfromJanuarythroughFebruary.Itdoesnotrequire inoculationbecausesprigsareinoculatedfromt heparentsoil(SollenbergerandCollins,2003). Afteratwo yrestablishmentperiodforstandsthatarenotirrigated,mostgrowthoccursfrom ApriltoSeptember(SollenbergerandCollins,2003). Perennialpeanuttoleratescontinuousstockingifsuffic ientresidualherbageremains (Sollenbergeretal.,1989;Ortega S.etal.,1992;HernndezGarayetal.,2004).Ifperennial peanutpastureiscontinuouslystocked,theminimumallowablepastureheightis15 cm(Ortega S.etal.,1992).Ifrotationally stocked,pastureswillpersistwithaminimumstubbleheightof10 cmand6weeksrest(Ortega S.etal.,1992).Pastureshavebeenmaintainedformorethan20yr withpropermanagement.Nutritivevalueishigh(13to18%CP;60to70%IVDMD)andcattle m aygain0.93kg/donperennialpeanutversus0.68kg/donpurestandsofotherwarm season legumes(Sollenbergeretal.,1989). Insitu DMdegradationofbothleavesandstemsisabove 60%(Buloetal.,1994). Amongcultivarsofperennialpeanut,Arbroo kandFlorigrazearethemostcommonly utilizedinFlorida,andFlorigrazeismoresuitedtocontinuousstockingandismorecoldtolerant (HernndezGarayetal.,2004).Inarecentstudy,theCPconcentrationandinvitroorganic matterdisappearance(I VOMD)ofFlorigrazeweregreaterthanthoseofArbrook,butHolstein heiferADGwasnotdifferentbetweencultivarsandwasatleast0.59kg/d(HernndezGarayet al.,2004).WhencalvesweregrazedonaFlorigrazeperennialpeanutcreepareainfestedwit h bahiagrass,theypreferentiallygrazedtheperennialpeanut,andtheirADGwasincreasedby0.14 kg/drelativetothoseofcalvesonbahiagrasspasturewithnocreeparea(Williamsetal.,2004). Perennialpeanutisregardedasthebestperennialwarm s easonlegumefortheGulfCoast

PAGE 37

37 region,butestablishmentcostsanddurationoftheestablishmentperiodlimititsadoptionbyhay andbeefcattleproducers. SeededWarm SeasonLegumes Annual P eanut Annualpeanut( Arachishypogaea L.)wasplantedon1.2m illionacresintheUnitedStates producingoverabillionkgofpeanutsin2007(NASS,2007).ThiscroporiginatedinSouth America,buthasspreadthroughtheAmericas,Africa,AsiaandPacificIslands.Itistropically adaptedandgrowsbestwhenaver agerainfallis500to1,200mm.Annualpeanutiscurrently grownfortheseedproducedunderground,butitwasusedhistoricallyforlivestockproduction (Johnsonetal.,1979).Growthcharacteristicsvarywithcultivarandseveralcultivarsexist. Sel ectionhasfocusedonimprovingseedproduction,butcultivarsarenowbeingevaluatedfor forageproduction(Blmmeletal.,2005).Annualpeanutforagecanproduceyieldsof1,000to 2,500kgDM/haannuallyandthepotentialinsituDMdegradabilityis approximately70%(Bulo etal.,1994;Muir,2002).TheCPconcentrationmayrangefrom13to20%anditdecreaseswith maturity(Muir,2002).TheNDFconcentrationofannualpeanutcanrangefrom30 50%andis cultivardependent(Noualaetal.,2004;Bl mmeletal.,2005).TheADFandADL concentrationsrangefrom21to26%and3to5%,respectivelyandtheseconcentrations decreasewithmaturity(Muir,2002).Morphologyandagronomictraitsvarymoreextensivelyin cultivarsofannualpeanutthanother cultivatedplants(CarvalhoMoretzsohnetal.,2004) contributingtotherangeofchemicalcomposition. Thequalityofannualpeanutforagemowedpriortoharvestingthenutshasbeenreported tobeequaltoalfalfa(Morrison,1956;Yang,2005).Whenca ttlegrazedannualpeanut,milk yieldincreasedby2%andsteersweresuccessfullyfinished(Morrison,1956).Thecropresidue afterharvestingthenutsisalsoutilizedbylivestockproducersforfeed.Whenpeanutstoveris

PAGE 38

38 fed,goatsselectnutsandle avesandrumenfillislessthanthatfrombermudagrasshay,dueto increaseddigestibility(Packard,2004).Inastudycomparingthehaulmsof11cultivars,CP concentrationsrangedfrom10to18%,NDFconcentrationsfrom33to44%,andADL concentration sfrom4to6%(Blmmeletal.,2005).Whenthehaulmswerefedtosheep,OM digestibilityof66to77%wasreported(Blmmeletal.,2005).Becauseitisalegumewitha lowwater solublecarbohydrateconcentrationandhighbufferingcapacity,ensiling canbe difficult(Yang,2005).Yet,annualpeanuthasbeensuccessfullyensiled(Johnsonetal.,1979; Cheongetal.,2002;Yang,2005),andannualpeanutsilageismorereadilyconsumedthancorn silagebydairyheifers(Johnsonetal.,1979).Fungicid escommonlyappliedtoannualpeanut arenotlabeledforfeedingtolivestock.Therefore,caremustbetakentoavoidfeeding fungicide treatedannualpeanutforagetolivestock.Despiteitspromisingnutritivevalue,annual peanutforageisnotwidelyu sedasaruminantfeedbecauseofthelocalizedproductionandthe difficultylocatingforagethathasnotbeentreatedwithfungicide. Soybean Initiallysoybean( Glycinemax (L.)Merr.)wasintroducedtotheUnitedStatesasaforage cropinthe1800s,bu ttheemphasisshiftedtograinproductionsoonafterwards(Sheafferetal., 2001).SoybeanwasintroducedtotheUnitedStatesfromAsiaandAustralia,andisperhapsthe worldsmostimportantcrop.ItisamajoroilseedcropintheUnitedStates(Dig gsetal.,1999) andisusuallygrownasapurestandorinassociationwithwarm seasonannualgrasses.Itis seededat50to115kg/hainMayandrequiresinoculationwith Bradyrhizobiumjaponicum (SollenbergerandCollins,2003).Asthestanddensity increases,thestemdiameterdecreases, whichimproveshaydryinginFloridashumidenvironment,and400,000to500,000plants/hais anidealplantdensityforadequateforageproduction(Sheafferetal.,2001;Sollenbergerand

PAGE 39

39 Collins,2003;Seiteretal .,2004).Whileadaptedtowell drainedsoils,soybeanisnottolerantof acidicorlowfertilitysoils(SollenbergerandCollins,2003). Thisannualspeciesdoesnotregrowafterdefoliationsoitprovideslimitedgrazing,and soybeanhaymustbecondi tionedtopreventdecreasesinnutritive(SollenbergerandCollins, 2003).TheCPconcentrationvarieswithmaturityduetothelargeamountofreservesinthe plantforseedproduction(17%CPat50%floweringversus21%CPat90%podfill),but digestib ilityislessvariable(59%IVDMDat50%floweringversus61%IVDMDat90%pod fill;Minsonetal.,1993;SollenbergerandCollins,2003).Late maturingcultivarsproduced 6,725kg/haincentralFloridaandcontainedgoodnutritivevalue(15to18.5%CP; 59to64% IVDMD;SollenbergerandCollins,2003).Suchcultivarsproducegreateryieldandhavethinner stemsthanearlier maturingcultivars(SollenbergerandCollins,2003).Ideallyharvestor grazingoccursatstageR6orR7whenqualityandDMproduc tionareoptimizedbutleaflossis minimized(Sheafferetal.,2001).SoybeanhasbeenensiledsuccessfullyinAustralia(Minsonet al.,1993),andanexperimentinsouthwestVirginiaproduced1,860kgofsilagefrom2,130kgof harvestedsoybean(Allen etal.,2000).Thisamountofsilagewasenoughtosupplement growingAnguscrossbredsteersgrazingryegrasspasturesfor73dandprovidedanADGof 0.51kg/head/d(Allenetal.,2000). Soybeancontainsphytoestrogenswhicharephenoliccompoundstha tproduceestrogen analogsastheyaremetabolized(CollinsandHannaway,2003).Phytoestrogenshavecaused infertilityinfemalesheepgrazingsubterraneanclover( Trifoliumsubterraneum L.)which contains5%DMofphytoestrogens.Cowsandheifersarel essaffectedbythissecondarytoxin (CollinsandHannaway,2003)eventhoughtherearereportsofinfertilityincattleconsuming cloverrichinphytoestrogens(Bennettsetal.,1946).Soyproductshaveapproximately0.25%

PAGE 40

40 DMisoflavoneswhichisoneof thepredominantformsofphytoestrogensinplants(Adams, 1995).Whenheiferswerefed1.36kgDM/dwholesoybeanseeds,theirtimetoestrousandtheir estrousresponseaftersynchronizationwasdelayedversusheifersfedsimilarconcentrationsof nutrie ntsfromdifferentsources(Funston,2004).Feedingasoybean baseddietthatsupplied75 g/dofphytoestrogensresultedinareducedpregnancyrateandincreasedurinaloutputof phytoestrogeninHolsteincowsbecauseoftheinfluenceofphytoestrogenso nprostaglandin synthesis(Woclawek Potockaetal.,2005).Harvestingsoybeanforagepriortopoddevelopment reducesthephytoestrogenrisk;however,thisdecreasesDMyieldandnutritivevalue. Nevertheless,becausetheleafandstemdilutesthephytoe strogenconcentrationwhenforage soybeanisconsumed,itshouldnotadverselyaffectthereproductionofbroodcowsand replacementheifers.Moreresearchonthegrowthandreproductiveresponsesofruminant supplementationwithsoybeanforagearerequir edtofacilitateitsadoption. Cowpea Cowpeahashistoricallybeenusedasacovercropforsoilconservationandfertility improvement,andrecentlyithasbeenplantedforseedproductionorasabrowsefordeerora quailhabitat(Minsonetal.,1993;S ollenbergerandCollins,2003).Indevelopingcountries, flourproducedfromdriedcowpeaseedisfedtoinfantsandchildren,andblackeyedcowpeas areconsumedintheUnitedStates.Cowpeaisnotdroughttolerant;therefore,itonlypersistsin pastur esifthefirstyrofgrowthismoistenoughtoallowdevelopmentofaseedbank(Jones, 2001).Cowpeaismoreadaptedtoalkalinesoils(pH7.8)andlesssusceptibletoironchlorosis whengrownonsuchsoilsthanotherwarm seasonlegumes(Gricharetal .,1995).Undertropical conditions3,500to8,500kgforageDM/hacanbeproducedannually.Underaridconditions, productionislimitedto4,300to5,600kgforageDM/haannuallywithinfrequentirrigation (Minsonetal.,1993;Muir,2002).TheCPcon centrationaverages17to21%throughthe

PAGE 41

41 growingseasonanddecreasesto14to22%inthefall(Muir,2002).Aciddetergentfiber concentrationrangesfrom21to22%duringthegrowingseason,butdecreasesto19%inthefall (Muir,2002).Aciddetergen tligninconcentrationaverages4%throughthegrowingseason,and doesnotvaryastheplantmatures(Muir,2002).Wholeplantandleafinsituandinvitro digestibilitiesaregreaterthanthoseofotherwarm seasonlegumes(Minsonetal.,1993;Muir, 2 002). Cowpeaisrecommendedforseason longgrazingifthecostofplantingandmaintenance canbejustifiedbyincreasedreturns(Muir,2002).Whendairygoatsgrazingandbrowsingthe trees,bushes,shrubs,andgrassesindigenoustowesternSudanwere fedcowpeahayasaprotein supplement,milkyield,weightgainthroughthedryseason,andplasmaphosphorous(P) concentrationwereincreased(AhmedandNour,1997).InMissouri,lambsgrazingcowpea gainedmoreweightandhadsimilarcarcasscharacter isticsasthosefedcornandeither cottonseedorsoybeanmealinadrylot,implyingthatcowpeacanbeutilizedinsteadof concentratedietstofinishlambs(KieslingandSwartz,1997).Cowpeaisbecomingmorewidely utilizedforwildlifebutmoreresea rchonitsqualityandpersistenceisrequiredbeforeitcanbe widelyadoptedbylivestockproducersintheSoutheast. Pigeonpea PigeonpeaisgrownintensivelyinthetropicsandsubtropicsofAsia,SouthAmerica,and Africaandisoneofthemostdivers elyutilizedlegumecrops.Driedseedsareusedasflour (dahl)forcooking,greenseedsareeatenasvegetables,seedsandleavesarefedtoanimals, stemsareusedasfuelandasstrawtomakehutsandbaskets,anddifferentpartsoftheplantare used tocureskin,liver,lung,andkidneyillnesses(NeneandSheila,1990).Thisdrought tolerantperennialisgrownasanannualandafteritisharvestedat180d,itregrowstoprovide foragetolivestock(NeneandSheila,1990).Late maturingvarieties thatflowerafterthe

PAGE 42

42 shortestdoftheyrareintercroppedwithvariousothergrainandlegumecrops,whileearly maturing,photoperiod insensitiveforagevarietiesaregrownasmonocultures(FarisandSingh, 1990;NeneandSheila,1990;Troedsonetal., 1990).Over11,000cultivarsfrom52countries areavailableatthegenebankoftheInternationalCropResearchInstitutefortheSemi Arid TropicsinIndia(Remanandan,1990).TwocultivarsdevelopedattheUniversityofGeorgiaand areadaptedtothe southeasternUnitedStateswerereleasedin2008.Seedscommonlycontain19 to26%CP,butthisvariesgreatlywithcultivar,andforagescancontainupto20%CP (Remanandan,1990;Behling,2004).Pigeonpeaisdroughttolerant,bestadaptedtowell drai ned soils,andwilltolerateslightlyacidicsoils,butismoresensitivetoextremelyacidic(pH<5.0) orsalinesoilsthancowpea(Troedsonetal.,1990).StudiesinOklahomareportedyieldsfrom 1290kgDM/hainlate maturingcultivarsto2,500kgDM/ hainearly maturingcultivars60d afterplanting(Raoetal.,2002;2003).At120dafterplanting,thelate maturingcultivar producedanaverageof12,530kgDM/haandtheearly maturingcultivarsproducedanaverage of10,000kgDM/haduring3yrof experimentation(Raoetal.,2002;2003).Stemproportion increasesascuttingintervalisdecreasedbut8 12weekintervalsareidealforcutting,andthe late maturingcultivarsaremoretoleranttodefoliation(FarisandSingh,1990).Beefcattlerate ofgainonpigeonpeapasturewas0.7to1.25kg/head/d,whichindicatesahighnutritivevalue (FarisandSingh,1990).Pigeonpealeavescanserveasasubstituteforthevitamins,protein,and mineralsavailableinalfalfainareaswherealfalfacannot grow(FarisandSingh,1990). ResearchintheUnitedStateshasshownthatcattlewillgrazepigeonpeawhenitis2.5to 46cmtall,afterwhichcattleprefertograzeotherplantsuntilpodsbegintoform(Behling, 2004).StudiesinOklahomahaveshown thatlate maturingcultivarshavepotentialforgrazing orproducinghayorsilage,whereasearly maturing(120d)cultivarsaresuitableforgrazingand

PAGE 43

43 seedproduction(Raoetal.,2003;Behling,2004).Theidealtimeofharvestisduring physiological maturitywhenIVDMDisstillsimilartothatatmidseason(57%DM),butDM productionisgreatest(Raoetal.,2003).Supplementingpigeonpeatogoatsgrazingplants indigenoustoTanzaniaincreasedintake,growthrateandreturnoninvestment(Karachia nd Zengo,1998). Thecondensedtanninconcentrationofpigeonpearangesfrom0.4to4.3%DMdepending onthecultivar(Alexanderetal.,2007).Condensedtanninsareconcentratedintheseedandthe typicalconcentrationincream colored,smoothpigeonp easeedsis0.75%DM,whereasin brown colored,wrinkledpigeonpeaseedsitis1.44%DM( Ene Obong,1995 ).Differencesoccur betweencultivarsbecausethecondensedtanninconcentrationvarieswithcoloroftheseedcoat wherethecondensedtanninisconc entrated(Reddyetal.,1985),andtheseedcolorvariesamong pigeonpeacultivars(Chintapallietal.,1997).Also,plantsgrownunderstressessuchashigh altitudeorsolarradiation,nutrientdeficiency,droughtorfrequentdefoliationtendtohave gr eatercondensedtanninconcentration(Larcher,2003;Alonso Amelot,2007). Despitetheirbenefits,warm seasonlegumesarenotwidelyutilizedinlivestockdietsin theSoutheast.Relativelylittleresearchhasbeendirectedatinvestigatingthepotentia luseof cowpea,pigeonpea,soybeanandannualpeanutasproteinsupplementsforruminantsinthe Southeast.Thereisalsolittlepublishedontheperformanceofruminantsfedhays,silages,or creepfeedsbasedonthesewarm seasonlegumes.Thisresearc hwasdesignedtoevaluate differentmethodsofincludingtheselegumesinruminantlivestockdietsinasubtropical environmentandtoenhanceknowledgeaboutthebenefitsofincludingthesewarm season legumesinlivestockdiets. Thespecificobjective softhiscollectionofresearchprojectswere:

PAGE 44

44 Todeterminetheherbagemass,leaf to stemratio,andnutritivevaluecharacteristicsof soybean,cowpeaandpigeonpeainFlorida(Chapter3), Todeterminethefermentationcharacteristicsandnutritivevalu eofensiledperennial peanut,annualpeanut,cowpeaandpigeonpea(Chapter5), Todeterminethefeedintake,digestibility,andNbalanceoflambsfedbahiagrasshayor haylagesupplementedwithhaysorhaylagesmadefromperennialpeanut,annualpeanut, soybean,cowpea,andpigeonpea(Chapters4and6), TodeterminetheeffectofcreepgrazingwithperennialpeanutorcowpeaonADGofbeef cow calfpairsgrazingbahiagrasspastureinFlorida(Chapter7).

PAGE 45

45 CHAPTER3 FORAGEPRODUCTIONAN DNUTRITIVEVALUEOF THREEWARM SEASON LEGUMES Introduction InFloridaandmuchofthesouthernUnitedStates,bahiagrass( Paspalumnotatum Flgge) andbermudagrass( Cynodondactylon (L.)Pers.)arethemainpastureforages(G atesetal., 2001).Theavailabilityofbahiagrassandbermudagrassforwintergrazingislimiteddueto decreasingdaylengthanddecreasingnighttemperatures,respectively(Blountetal.,2001;Gates etal.,2001).Inadditiontotheseasonalquantity limitation,thequality(digestibilityandCP concentration)oftheseforagesdeclinesastheymatureandisinsufficienttomeetthenutrient requirementsofgrowingandlactatingcattleinmid to latefall(Dubleetal.,1971;Williamsand Hammond,1999; Johnsonetal.,2001).Warm seasonlegumeshavethepotentialtoprovidethe neededsupplementarynutrients,andwhenstoredashay,silageorhaylage,theycanbefedinthe wintertosupplementstoredandstockpiledgrasses,suchasbahiagrassandberm udagrass. Cowpea( Vignaunguiculata (L.)Walp.)hashistoricallybeenusedasacovercropforsoil conservationandsoilfertilityimprovement.Itisgenerallyplantedforlivestockgrazingordeer browsing,seed,orasaquailhabitat(Minsonetal., 1993;SollenbergerandCollins,2003). Underhighrainfallconditions,upto8,500kgDM/hacanbeproducedannually,butinarid conditionswithinfrequentirrigationonly4,300to5,600kgDM/haperyrhasbeenreported (Minsonetal.,1993;Muir,2002) .InnorthTexas,CPconcentrationofcowpeaaveraged18% throughthesummeranddeclinedinthefall(Muir,2002). Pigeonpea ( Cajanuscajan (L.)Millsp.)iscommonlygrownforgrainandisthesixthmost widelygrownlegumeintheworld(NeneandSheila, 1990).Inmanycountries,t hisdrought tolerantperennialisgrownasanannualgraincrop.Aftergrainharvestat180d,pigeonpeacan regrowtoprovideforageforlivestock(NeneandSheila,1990).Pigeonpeacultivarshavebeen

PAGE 46

46 developedinGeorgiaa ndMississippiandhavebeentestedforgrainandforageproductionin Florida,OklahomaandVirginia(Phataketal.,1993;Bhardwajetal.,1999;PrineandFrench, 1999;Raoetal.,2002;2003).Fivecultivarsofpigeonpeaproducedupto12,000kgDM/ha of forageannuallywithupto19%CPand70%IVDMD;herbagemasswasmaximizedlateinthe growingseasonwhiletheCPconcentrationandIVDMDweregreatestearlyinthegrowing season(Raoetal.,2002;2003). Soybean( Glycinemax (L.)Merr.)isperhap stheworldsmostimportantlegumecropand isamajoragriculturecropforoilseedproductionintheUnitedStates(Diggsetal.,1999).Late maturingcultivarsproducedmorethan6,000kgDM/haincentralFloridaandcontained15to 18%CPand59to6 4%IVDMD(SollenbergerandCollins,2003).Nutritivevaluevarieswith maturityduetothelargeamountofreservesintheplantforseedproduction.Forinstance,CP concentrationincreasedfrom17%at50%floweringto21%at90%podfill(Sollenberger and Collins,2003).Digestibilityhasbeenfoundtobemoderatelyvariableinsoybeanforageand rangesfrom59%IVDMDat50%floweringto67%IVDMDat90%podfill(Minsonetal., 1993;SollenbergerandCollins,2003). Comparativestudiesoftheforage yieldpotentialandnutritivevalueofthese3warm seasonlegumesinthesoutheasternUnitedStatesarelacking.Thisinformationisrequiredto determineidealwarm seasonlegumesforenhancingruminantproductionintheSoutheast.The objectiveofth isstudywastoquantifyandcomparematurity relatedchangesintheherbage mass,chemicalcomposition,invitrotruedigestibility(IVTD),andleaf to stemratioofcowpea ( cv.Ironclay ),soybean(cv.Pioneer97B52)andpigeonpea( cv. Georgiatwo )grown inNorth Florida.

PAGE 47

47 MaterialsandMethods FieldPreparationandForageSampling Ineachof3yr,legumesweregrownattheNorthFloridaResearchandEducationCenter inMarianna,FL(31N).SoilontheexperimentsitewasChipolaloamysand(loamy,kaol initic, thermic,ArenicKanhapludults)andOrangeburgloamysand(fine loamy,kaolinitic,thermic, TypicKandiudults).In2005,afallowfieldwaspreparedbychiselplowingafterapplying dolomite(3,300kg/ha)andfertilizer(330kg/haof0 20 40 0.5ra tioofN:P 2 O 5 :K 2 O:Bwith gypsumfiller).In2006,thefieldwaspreparedbyplowingafterapplyingcalciticlime(2,250 kg/ha)andfertilizer(310kg/haof0 18 10 10ratioofN:P 2 O 5 :K 2 O:S).Thesamequantityof fertilizerwasappliedin2007,buttheco mpositiondiffered(7 18 29ratioofN:P 2 O 5 :K 2 O).All fertilizerapplicationswerebasedonsoilanalysis.Immediatelypriortoplanting,seedswere inoculatedwith Bradyrhizobium spp.(BeckerUnderwood,Inc.,RoyalPeat,Ames,IA)and drilledat56kg/h aand15 cmrowspacingineachof4replicateplots.Eachreplicatewas plantedineachof4blockslocatedacrossthetwosoiltypes.Inyr1and2,plotsizewas4,050 m 2 andinyr3plotswere88m 2 .Plotsizewasgreaterinyr1and2becausethef oragewas requiredforsubsequentfeedingtrials.Plantingdatesvariedwithweather;therefore,planting datesforyr1(2005),2(2006),and3(2007)wereMay9,26,and10,respectively.Plotswere irrigatedwith3cmofwaterwithin3dofplantingi neachyrandirrigatedagainiftherewasno rainfallafter7consecutived.Theirrigationequipmentmalfunctionedshortlyafterplantingin 2006,consequentlysoybeandidnotemergeevenafter2plantingsandtheothercropswere severelyaffectedbyd rought.Consequently,the2006cropdatawerenotincludedinthisreport. MonthlyrainfallandtemperaturedatawererecordedviatheFloridaAutomatedWeather Networklocatedonsite(FAWN,2008).Rainfallandtemperatureaveragesoverthelast30yr wereobtainedfromtheFloridaClimateCenter(FCC,2008).

PAGE 48

48 SampleCollectionandChemicalAnalyses Foragesamplesweretakenwithmechanicalclippersanda0.2 m 2 areawasharvested. Samplesweretakenafterplantheightreachedapproximately30cmand continueduntilthe recommendedmaturitystagefortherespectiveforagesthatmaximizedbothherbagemassand nutritivevalue.Recommendedmaturitiesarewhenpodsbegantoturnyellowforcowpea (NDA,1997),podsettingforpigeonpea(Hourou,2006),an dstageR6(fullsizeseedinpodsat oneofthe4uppermostnodesandcompletelyunrolledleaves)forsoybean( Coffeyetal.1995; Sheafferetal.,2001).Todetermineleaf to stemratio,leaveswereremovedatthestemnode andleafandstemtissueswer eweighedandanalyzedforDMconcentration. Wholeplant,leafandstemsamplesweredried(60 o C )for48hinaforcedairovenand groundtopassthrougha1 mmscreeninaWileymill(ArthurH.ThomasCompany, Philadelphia,PA).TotalNconcentrationw asdeterminedbyrapidcombustionusingamacro elementalNanalyzer(Elementar,varioMAXCN,ElementarAmericas,MountLaurel,NJ)and usedtocomputeCP(CP=N6.25).Neutraldetergentfiberwasanalyzedusingthemethodof VanSoestetal.(1991). AmylaseandsodiumsulfitewereusedforNDFanalysisandresults wereexpressedonaDMbasis.TheANKOM(2005a)adaptationoftheVanSoestetal.(1966) methodforanANKOMDaisy II Incubator (ANKOMTechnology,Macedon,NY) andan ANKOM200FiberAna lyzerwasusedtodetermineIVTD. StatisticalAnalyses Theexperimentaldesignwasarandomizedcompleteblock.Datawereanalyzedwith PROCMIXED(SASInst.Inc.,Cary,NC).Themodelusedtoanalyzeherbagemass,leaf to stemratio,andnutritiveva lueofleaf,stemandwholeplanttissueincludedyr,foragespecies, weekafterplanting(WAP),block andtheinteractions.AteachWAP,significantmeanswere separatedusingaPDIFFstatement.Polynomialcontrastsforlinear,quadraticandcubiceffec ts

PAGE 49

49 wereusedtodeterminetrendsforeachparameterthroughthegrowingseason.Significancewas declaredat P <0.05andtendenciesat P >0.05and 0.10. Results Theamountanddistributionofrainfallduringthegrowingseasonineachyrvaried(Figure 3 1).Duetohurricaneactivity,2005hadanunusuallywetgrowingseasonwhereas,2006and 2007weredrier.In2006,therainwasmor esporadicandusuallylessthan0.5cmwasrecorded atgivenrainevents.Averagemonthlytemperaturesweresimilarto30 yraveragesineachyr (Figure3 2).Therewerenoyrforagespeciesinteractions( P 0.10)foranyoftheresultsin thisstudy ,sodataarepresentedasmeansacrossyr. WholePlantHerbageMassandLeaf to stemRatio Therewasalinearincrease( P <0.01)inherbagemassineachlegumeasWAPincreased (Figure3 3).However,therewerenodif ferences( P >0.10)inherbagemassbetweenforages until10WAPwhensoybeanandpigeonpeahadgreater( P <0.01)herbagemassthancowpea. Thesedifferencespersisteduntiltherespectiverecommendedharveststagesexceptthatcowpea andpigeonpeahads imilarherbagemassat12WAP.Pigeonpeareachedthe recommended Figure3 1.AveragemonthlyrainfallinMarianna,Florida,duringthreeyearsof experimentation

PAGE 50

50 harveststage14WAP,whereassoybeanandcowpeareachedtheirrecommendedharveststages at16and20WAP,respectively. Leaf to stemratiodecreasedwith maturityafteraslightinitialincreaseinallforages (Figure3 4).At8WAP,theleaf to stemratioofcowpeawasgreaterthanthatofpigeonpeaand thatofsoybeanwassimilartotheothers.From10to14WAP,theleaf to stemratioofcowpea wasgre aterthanthoseofpigeonpeaandsoybean,whichweresimilar.Attherecommended harveststageofsoybean(16WAP),cowpeastillhadagreater( P <0.01)leaf to stemratiothan soybeanbutthecowpealeaf to stemratiodecreasedrapidlyafterwards. Che micalCompositionandIVTD TheCPconcentrationofeachforagedecreasedthroughthegrowingseason(Figure3 5). Between8WAPandtherespectiverecommendedharveststages,cowpeahadthegreatestCP concentration,whereassoybeanhadagreaterCPconce ntrationthanpigeonpeafrom10 WAPto therecommendedharveststageforpigeonpea.WholeplantNDFconcentrationsincreasedwith Figure3 2.Averagemonthlytemperature(C)inMarianna,Florida,duringthreeyearsof experimentation

PAGE 51

51 Figure3 3. Changesinherbagemass(kgDM/ha)ofcowpea,pigeonpeaandsoybean Figure3 4.Leaf to stemratioofcowpea,pigeonpea,andsoybean 1 Weekafterplanting(WAP) 2 Linear(L)polynomialcontrastforWAP,***( P <0.001) Means ateachWAPwithoutacommonsuperscriptletterdiffer( P <0.05). SEM=932kgDM/ha;Yeareffect( P >0.9);Yearforagespecies( P >0.6) 1 Weekafterplanting(WAP) 2 Linear(L);quadratic(Q);cubic(C)polynomialcontras tsforWAP,***( P <0.001); *( P < 0.05) Means ateachWAPwithoutacommonsuperscriptletterdiffer( P <0.05). SEM=0.05;Yeareffect( P >0.2);Yearforagespecies( P >0.1)

PAGE 52

52 maturityinpigeonpeaandcowpea,andtheincreaseoccu rredatagreaterrateinpigeonpea. Afteraninitialincrease,theNDFconcentrationofsoybeanpeakedat8WAPandthendecreased gradually.PigeonpeahadagreaterNDFconcentrationthantheotherlegumesbetween10and 14WAP,andsoybeanhadagreat erNDFconcentrationthancowpeabetween8and14WAP. WholeplantIVTDdecreasedwithmaturityinpigeonpeaandcowpea,buttherateandextentof thedecreasewasgreaterinpigeonpea.TheIVTDofsoybeandecreasedtoaminimumat10 WAPandthenincre ased.From8to14WAP,cowpeahadthegreatestIVTD,followedby soybean,buttheIVTDofcowpeaandsoybeanweresimilarat16WAP. StemCPconcentrationsdecreasedrapidlywithmaturityinpigeonpea,butincreasedtoa peakat12WAPandthendecreas edincowpea(Figure3 6).Afterdecreasingtoaminimumat8 WAP,theCPconcentrationofsoybeanstemsincreasedslightlyuntil16WAP.TheCP concentrationofcowpeastemswasconsistentlygreaterthanthoseofsoybeanorpigeonpea stems.Soybeanand pigeonpeahadsimilarstemCPconcentrationsuntil16WAP,whensoybean stemshadgreaterCP.TheNDFconcentrationofpigeonpeastemsincreasedwithmaturity whereasthoseofcowpeaandsoybeandidnotincreaseappreciablyafter8WAP.Pigeonpea stems consistentlyhadgreaterNDFconcentrationsthanthoseofsoybeanorcowpea,whichwere similarthroughoutthegrowingseason.TheIVTDofpigeonpeastemsdecreasedatafasterrate thanthatofcowpeastems.TheIVTDofsoybeanstemsdecreasedrapidlyf rom6to8WAP, remainedrelativelystableuntil14WAP,andthenincreased.Pigeonpeastemsconsistentlyhad thelowestIVTD,andcowpeastemshadgreaterIVTDthansoybeanstemsbetween8and12 WAP. ConcentrationofCPintheleavesofcowpeafluctua tedtoagreaterextentthanthoseof pigeonpeaandsoybeanduringthegrowingseason(Figure3 7).Cowpealeavesconsistentlyhad

PAGE 53

53 Figure3 5. WholeplantCPan dNDFconcentrations (DMbasis) and invitrotruedigestibility ( IVTD ) ofcowpea,pigeonpeaandsoybean a)CP,%;SEM=1.4;Yeareffect(P>0.2);Yearforagespecies( P >0.3) b)NDF,%;SEM=1.8;Yeareffect(P>0.1);Yearforagespecies( P >0.8) c)IVTD,%;SEM=1.7;Yeareffect(P>0.2);Yearforagespecie s( P >0.9) 1 Weekafterplanting(WAP) 2 Linear(L);quadratic(Q);cubic(C)polynomialcontrastsforWAP; ***( P <0.001); **( P <0.01) ; *( P >0.05) Means ateachWAPwithoutacommonsuperscriptletterdiffer( P <0.05).

PAGE 54

54 Figure3 6. Crudeprote i nandNDFconcentrations (DMbasis) and invitrotruedigestibility ( IVTD ) ofc owpea,pigeonpeaandsoybeanstems a)CP,%;SEM=1.1;Yeareffect(P >0.5);Yearforagespecies( P >0.5) b)NDF,%;SEM=1.2;Yeareffect(P>0.1);Yearforagespecies( P >0.5) c)IVTD,%;SEM=3.8;Yeareffect(P>0.2);Yearforagespecies( P >0.1) 1 Weekafterplanting(WAP) 2 Linear(L);quadratic(Q);cubic (C)polynomialcontrastsforWAP; ***( P <0.001); **( P <0.01) ; *( P >0.05) Means ateachWAPwithoutacommonsuperscriptletterdiffer( P <0.05).

PAGE 55

55 a)CP,%;SEM=1.8;Yeareffect(P>0.2);Yearforagespecies( P >0.9) b)NDF,%;SEM=1.9;Yeareffect(P>0.1);Yea rforagespecies( P >0.4) c)IVTD,%;SEM=1.6;Yeareffect(P>0.1);Yearforagespecies( P >0.3) 1 Weekafterplanting(WAP) 2 Linear(L);quadratic(Q);cubic(C)polynomialcontrasts forWAP ; ***( P <0.001);**( P <0.01);*( P >0.05); ( P <0.10 ) MeansateachWAPwithoutacommonsuperscriptletterdiffer( P <0.05). Figure3 7. Crudeprote i nandNDFconcentrations (DMbasis) and invitrotruedigestibility ( IVTD ) ofcowpea,pigeonpeaandsoybean leave s

PAGE 56

56agreaterCPconcentrationthansoybeanorpigeonpealeavesexceptat8WAPwhenCPconcentrationsofleavesweresimilaracrossspecies.PigeonpeaandsoybeanleaveshadsimilarCPconcentrationsat10WAP.LeafNDFconcentrationsincreasedappreciablywithmaturityinpigeonpeaandsoybean,buttheincreaseincowpeawasgradual.PigeonpeaandsoybeanleaveshadsimilarNDFconcentrationsthroughouttheexperiment,andcowpeahadlowerconcentrations.TheIVTDofcowpeaandsoybeanleavesdecreasedslightlywithmaturity,whereasthatofpigeonpeadecreasedbyabout30percentageunits.ThroughoutthegrowingseasonIVTDwasgreatestincowpealeavesandlowestinpigeonpealeaves.DiscussionWholePlantHerbageMassandLeaf-to-StemRatioCowpeaandpigeonpeaherbagemasswerecomparabletoreportedvalues(BrinkandFairbrother,1988;Muiretal.,2001,2002;Raoetal.,2003).Theherbagemassandleaf-to-stemratioofthesoybeancultivarweresimilartothosereportedformorethantencomparableforageandgrainsoybeancultivars(Sheafferetal.,2001;Mislevyetal.,2005).Theleaf-to-stemratiosofpigeonpeaandcowpeaandtheirdeclinethroughthegrowingseasonwereconsistentwithpreviousreports(Raoetal.,2003;MaryandGopalan,2006).Herbagemassandleaf-to-stemratiodifferencesamongthespeciesareduetomorphologicalandphysiologicaldifferences.Ironclaycowpeaisavining,lowgrowingplantwithlargetrifoliolateleavesandanindeterminategrowthhabit(Jonesetal.,1989).Thesoybeancultivarusedinthisexperimentwaslatematuring(VII),withupright,tall(1.5to2.0m)growth.Afterblooming(R1stage),theproportionofleafdeclinesthroughmaturityatR7stage(Fehretal.,1971).Pigeonpeaisatree-likelegumethatgrowstallandhasawoodymainstem(Masamaetal.,1997).Pigeonpeahassmall,unifoliolateandtrifoliolateleavesthatreachmaximuminterceptionoflightat9WAP,afterwhicholderleavesbegintosenesce(Muchow,1985;Raoet

PAGE 57

57 al.,2003).Pigeonpeaandsoybeanhadgreaterherbagemassthancowpeabecauseoftheir uprightgrowthhabita ndthickerstemswhichsupportedgreaterherbagemass.Cowpeahad greaterleaf to stemratiothansoybeanandpigeonpeabecauseithasanindeterminategrowth habit;therefore,itsleavesdidnotbegintosenesceasearlyasthoseofsoybeanandpigeonpea ChemicalCompositionandIVTD TheCPandNDFconcentrationsofcowpeawholeplant,leavesandstemsandthechanges withmaturityinthesecomponentswereconsistentwithpreviousreports(BrinkandFairbrother, 1988;Muldoon,1985;Muiretal.,2001; 2002).ForagesoybeanvarietiestestedbyScheafferet al.(2001)containedNDFandCPconcentrationssimilartothoseinthisexperimentatthe respectivematurities.TheCPconcentrationsofpigeonpeawholeplant,leavesandstemswere similartovalue spreviouslyreportedforthesamecultivar(Raoetal.,2003).TheIVTDof pigeonpeastemswerealsosimilartoIVDMDvaluesreportedpreviously(Raoetal.,2003),but wholeplantandleafIVTDvaluesinthecurrentstudywere10percentageunitslower than correspondingIVDMDafter10WAPintheRaoetal.(2003)study.Plantdensitiesgreaterthan 20,000plants/hacandecreaseherbageandleafmassandnumberofpodsandpod producing branchesinpigeonpea(AkinolaandWhiteman,1974).Theseedingra teinthisstudywas20 kg/hagreaterthanthatinthestudybyRaoetal.(2003),buttheherbagemassandleaf to stem ratioswerenotdifferentindicatingthatthegreaterseedingratedoesnotexplainthelowerIVTD valuesinthisexperiment.Reasons whydigestibilityestimateswerelowerinthisstudyarenot clearsincebothstudiesexaminedthesamecultivarundersimilargrowthconditions,andIVTD valuesaretypicallygreaterthanIVDMDvalues.Nevertheless,theinvivoapparentdigestibility stu dy(Chapter4)alsodemonstratedthatpigeonpeahadlowerdigestibilitythanthosereported previously.

PAGE 58

58 TheCPconcentrationsofcowpeaandpigeonpeadeclinedwithmaturityduetoa combinationofdecreasingleaf to stemratiosanddecreasingstemCPconce ntrationsmoreso thandecreasingleafCPconcentrations.TheCPconcentrationsofleavesareprimarily associatedwithenzymesforphotosynthesis(FieldandMooney,1986;Evans,1989),which decreaseslowlyasplantsmature(Gordonetal.,1982).Conseq uently,leafCPconcentration decreasesgradually.TheNDFconcentrationsofcowpeaandpigeonpeaincreasedwithmaturity becauseofthecorrespondingincreasesinleafandstemNDFconcentrationsanddecreasingleaf to stemratios.TheseincreasesinND FconcentrationandtheconcomitantincreasesinIVTD occurredatslowerratesincowpeabecauseithadagreaterproportionofhighlydegradable leaves.TheIVTDofpigeonpeadecreasedrapidlywithmaturitybecauseofthedevelopmentof thickfibrousste ms,andtheearlylossofleaveswithmaturity.Unlikecowpeaandpigeonpea, theIVTDofsoybeanincreasedafter10WAPbecauseofacorrespondingdecreaseinNDF concentration.Thistrendhasbeenreportedpreviously(Minsonetal.,1993)andisdueto the formationofhighlydigestiblepods. Thenutritivevalueoftheselegumeswouldbeoptimizediftheywereharvestedatorprior to8WAP,butharvestingearlysacrificestotalDMproduction.Basedontheirherbagemass, leaf to stemratioandnutritiv evalue,soybeanandcowpeahavemorepotentialasforagesfor ruminantsthanpigeonpea.Attherespectiverecommendedharveststages,theIVTDofsoybean andcowpeaweresimilarbutsoybeanprovidedgreaterherbagemassandcontainedlessCPthan cowpea. Therefore,cowpeaisabetteroptionforproteinsupplementationoflivestock,whereas soybeanhasgreaterbiomassproductionpotential.Becausesoybeandoesnotregrowfollowing defoliation,itisidealforprovidinglargequantitiesofqualityhay,si lageorhaylage.The indeterminategrowthhabitandregrowthpotentialofcowpeamakeitsuitableforgrazingaswell

PAGE 59

59 ashay,silageorhaylage.Pigeonpeaisrecommendedforgrazingcattleorstorageashayor haylageifitislessthan8WAPorifthet op66to75%oftheplantisharvestedatpodsetting (Hourou,2006).Pigeonpeawouldprovideexcellentbrowseforgoats,deer,orsheepbecauseof theirabilitytoselectleaftissuewithadequateCPconcentrationandIVTDfortheirgrowth. Whilealll egumeshadphysiologicallynormalherbagemassproductionintheenvironmentof NorthFlorida,soybeanandcowpeahavethegreatestpotentialtoprovidehighqualityforageto livestock.Ofthethreeforagestested,soybeanandcowpeahavethegreatestpo tentialtoprovide highqualityforagetolivestockinFlorida.

PAGE 60

60 CHAPTER4 WARM SEASONLEGUMEHAYOR SOYBEANMEALSUPPLEM ENTATIONEFFECTS ONTHEPERFORMANCEO FLAMBS Introduction InFloridaandmuchofthesouthernUnitedStates,bahiagrass( Paspalumnotatum Flgge) andbermudagrass( Cynodondactylon (L.)Pers.)arethe mainforagegrasses.Normally,the quantityofthesegrassesissufficienttomeetintakerequirementsofmostclassesofbeefcattle untilearlywinter;however,theirqualityisinsufficienttomeetnutrientrequirementsofgrowing beefcattlethrougho utthegrazingseasonduetolowDMdigestibilityandCPconcentration (Dubleetal.,1971;Johnsonetal.,2001).Legumesprovidehighqualitygrazingforruminants (Leepetal.,2002;Muir,2002)andtheycanbestoredasexcellentqualityhay.Supplem enting poorqualitybasalgrassdietswithlegumeshasincreasedtotalfeedintakeofruminantlivestock inmanystudies(MinsonandMilford,1967;MosiandButterworth,1985;Abreuetal.,2004). Legumesaregenerallymoredigestiblethangrasses;conseq uently,supplementinggrassbasal dietswithlegumesoftenincreasestotaldietdigestibility(MinsonandMilford,1967;Getachew etal.,1994;Abreuetal.,2004).Whengrassdietsthatdonotmeetmicrobialandruminant energyandNrequirementsarefed ,supplementationwithlegumesimprovesNretentionbythe ruminant(MosiandButterworth,1985;Matizhaetal.,1997). IntheUnitedStates,alfalfa( Medicagosativa L. )isthelegumemostcommonlyfedto livestock.Alfalfaisoftenstoredashighqual ityhay,silageandhaylageandisusuallyfedto growingandlactatingruminantstomeettheirnutrientrequirements.However,alfalfadoesnot persistinthewarm,moistclimateoftheGulfCoastregion( Prineetal.,1981 ).Perennialpeanut ( Arachisg labrata Benth. )isawarm seasonlegumeadaptedtothisregionandit isthemain foragelegumeinFlorida.PerennialpeanuthasgreaterCPconcentrationandinvitroorganic matterdisappearance(IVOMD)throughoutthegrowingseasonthanbahiagrass(Will iamsetal.,

PAGE 61

61 2004).However,p erennialpeanutissprig plantedandittakes1to2yrtoestablish;therefore,it maybemorecostlytoestablishthantropicallyadapted,seededwarm seasonlegumessuchas cowpea( Vignaunguiculata (L.)Walp. ),soybean( G lycinemax (L.)Merr.),orannualpeanut ( Arachishypogaea (L.)) (Frenchetal.,2006).Littleisknownabouthowruminantanimal performanceisaffectedbysupplementingbahiagrasshaywithperennialpeanuthayorseeded warm seasonlegumehays. Thisst udywasaimedatdeterminingthefeedintake,digestibility andNbalanceoflambsfedbahiagrass(cv.Pensacola)haysupplementedwithsoybeanmeal,or haysofperennialpeanut(cv.Florigraze),annualpeanut(cv. FloridaMDR98),soybean(cv. Pioneer97B 52),cowpea( cv. Ironclay) ,orpigeonpea( Cajanuscajan (L.)Millsp. cv. Georgia two). MaterialsandMethods ForageProduction LegumehayswereproducedattheNorthFloridaResearchandEducationCenterin Marianna,FL,(31N)andfedattheDepartmen tofAnimalSciences,UniversityofFlorida, Gainesville,FL. SoilontheexperimentsitewasChipolaloamysand(loamy,kaolinitic,thermic, ArenicKanhapludults)andOrangeburgloamysand(fine loamy,kaolinitic,thermic,Typic Kandiudults). Toprepare thefieldforplantingseededlegumes(soybean,cowpeaand pigeonpea),dolomite(3,300kg/ha)andfertilizer(330kg/haof0 20 40 0.5ratioof N:P 2 O 5 :K 2 O:Bwithgypsumfiller)wereappliedandthefieldwaschiselplowed.Seedsofeach ofthelegumeswe reinoculatedwith Bradyrhizobium spp.(BeckerUnderwood,Inc.,RoyalPeat, Ames,IA)anddrilledat56kg/haand15 cmrowspacingonfour0.405 haplots.Thelegumes wereplantedinMayandharvestedinAugustandSeptemberof2005attherecommended ma turitystageformaximizingbothDMyieldandnutritivevalue.Thiswaswhenpodsbeganto turnyellowforcowpea(NDA,1997),podsettingforpigeonpea(Hourou,2006),andstageR6

PAGE 62

62 (podwithfullsizeseedatoneofthefouruppermostnodesandcomplete lyunrolledleaves)for soybean( Coffeyetal.1995; Sheafferetal.,2001).Establishedstandsofperennial(4 yr old) andannualpeanut(6 yr old;selfreseeding)wereharvestedasfirstcuttingsinJuneand Septemberof2005,respectively.Eachlegume washarvestedusingamower conditioner(New Holland,Haybinemodel474,NewHollandAgriculture,NewHolland,PA)andturnedwithan inverter(NewHollandmodel144)after24h.Perennialandannualpeanutandcowpeawere harvestedtoastubbleheighto f10cm,whereassoybeanandpigeonpeawereharvestedto stubbleheightsof20and40cmbasedonpreviousrecommendationsfortherespectiveforages (Romeroetal.,1987;Mislevyetal.,2005;Hourou,2006).Legumeswererolledintosmall roundbalesus ingaVermeer504Lbaler(VermeerManufacturingInc.,Pella,IA).An establishedstandofbahiagrass (11 yr old) wasfertilized(130kg/ha70 0 40 8ratioof N:P 2 O 5 :K 2 O:S)inthespringandwasharvestedtoastubbleheightof8 cmasa6 wkregrowth (Cl aasDisco2650mower,ClaasManufacturing,Omaha,NE)andbaled(ClaasRollant660 baler,ClaasManufacturing,Omaha,NE)intoroundbales.Eachhaybalewasstoredinafully enclosedbarnfornomorethan5mo,andsubsequentlychoppedtoapproximately 8cmparticle lengthinatubgrinder(RotoGrind,model760,BurrowsEnterprises,Greeley,CO)tolimit refusals. Animals,FeedingandHousing AllanimalprocedureswereapprovedbytheUniversityofFloridaInstitutionalAnimal CareandUseCommittee.F orty twoDorper Katadhin crossramlambsweighing 30.6 5.5kg wereusedfortheexperiment.Beforetheexperiment,alllambswerevaccinatedwitha3 way enterotoxemia,coccidiosis,andtetanusvaccination(BarVacCD T,2mL/head,Boehringer Ingelhei mVetmedicaInc.,St.Joseph,MO),de wormed(Cydectin,1.5mg/kgBW,FortDodge,

PAGE 63

63 IA),weighed,andtheirhoovesweretrimmed.Lambswerestratified byweightandrandomly assignedto7treatments(6lambspertreatmentperperiod)inacompletelyrandomi zeddesign with2periods.Eachperiodcontained14dofadaptationtodietsand7dofmeasurement,and eachlambreceivedadifferentdietineachperiod.Lambswerefittedwithcanvasfeces collectionbagsandhousedinindividualmetabolismcratesad aptedforcollectionoffecesand urine.Waterwasprovided adlibitum and 20gofamineralpremix(UnitedSaltCorp.,Ranch HouseTraceMineralizedSalt,Houston,TX)wasaddedtothedietofeachlambdaily.The mineralmixcontained90%NaCl,3%Ca, 1%S,0.2%Fe,0.3%Mn,0.3%Zn,25mg/kgCo,150 mg/kgCu,90mg/kgI,and10mg/kgSe. Lambswerefed adlibitum (110%ofpreviousdays intake)dietsconsistingofbahiagrasshayaloneorbahiagrasshaysupplemented(50%ofdiet DM)withperennialpean uthay,annualpeanuthay,cowpeahay,pigeonpeahay,soybeanhay,or soybeanmeal(4.25%ofdietDM).Thesoybeanmealinclusionlevelwasaimedatmatchingthe averageCPconcentration(10.8%DMbasis)ofthelegumediets.Thebahiagrassandrespective legumesupplementswerehand mixedandofferedinthesamefeedtroughat0800and1500. Thesoybeanmealwastopdressedonthebahiagrasshayandfedatthesametimeastheother diets. SampleCollection Samplesofeachfeedweretakendailyduringt he7 dcollectionperiodanddailyrefusals wereweighedandstored.Totalfecaloutputwascollecteddailyfromeachlamb,weighed,anda 10%subsamplewasstored( 20 o C )forsubsequentanalysis.Theweightandvolumeofdaily urineoutputwasrecorded fromsixlambspertreatmentineachperiod.Sulfuricacidwasadded tosubsamples(AppendixA)ofurinetoensurethatthepHremainedbelow3.0andtheurinewas stored( 20 o C )forfurtheranalysis.Lambswereweighedandbloodsampledbyjugular venip uncture ond0,21,and42. AVacutainertube(BD,FranklinLakes,NJ)containingsodium

PAGE 64

64 heparinanticoagulantwasusedtocollect10mLofwholebloodfromeachlambandthetubes werestoredonice.Thebloodwascentrifugedat 1920 g for20minat4 o Ctoseparatethe plasma,whichwasstoredat 20 o Cuntilanalyzed. Ruminalfluidwascollectedfrom28 randomlyselectedlambs(4randomlyselectedpertreatment)onthelastdofPeriod2by aspirationfromorally inserted stomachtubesat0,2.5,5,7 .5and10hafterthemorningfeeding. Arepresentative(100mL)samplewasanalyzedimmediatelyforpH (Accumet,modelHP 71, FischerScientific,Pittsburg,PA)and acidifiedwithconcentratedH 2 SO 4 ,centrifugedfor30min at4 o Cand2795 g ,andfrozen ( 20 o C)forsubsequentanalysis. ChemicalAnalyses Samplesoffeed,ortsandfecesweredriedat60 o C for48 hinaforcedairovenandground topassthrougha1 mmscreeninaWileymill(ArthurH.ThomasCompany,Philadelphia,PA). Sampleswereanalyz edforDMbyovendryingat105 o Covernight,andforashbycombustionin amufflefurnaceat600 o Covernight.TotalNwasdeterminedbyrapidcombustionusinga macroelementalNanalyzer(Elementar,varioMAXCN,ElementarAmericas,MountLaurel, NJ)a ndusedtocalculateCP(CP=N6.25).Neutraldetergentfiberwasanalyzedusingthe methodofVanSoestetal.(1991).AmylaseandsodiumsulfitewereusedforNDFanalysisand theresultswereexpressedonaDMbasis.Feedsampleswereanalyzedfor ADFandADLwith themethodofAOAC(1990).TheANKOM(2005a)adaptationoftheVanSoestetal.(1966) methodforanANKOMDaisy II Incubator (ANKOMTechnology,Macedon,NY) andthe ANKOM200FiberAnalyzerwasusedtodetermineIVTD.Apparentdigestibi lityofDM,OM, NandNDFwerecalculated.Condensedtannin(CT)concentrationofforageswasanalyzedwith themethodofTerrilletal.(1992).Quebrachotannin(UnitnATO,BuenosAres,Argentina) waspurifiedwithSephadexLH 20(GEHealthcareLifeSc iences,Piscataway,NJ)accordingto

PAGE 65

65 AsquithandButler(1985)asmodifiedbyHagerman(1994).Condensedtanninresultsare expressedasquebrachotanninequivalents. UrinewasanalyzedforNbyrapidcombustionwiththeelementalNanalyzerandfortot al purinederivatives(PD)asallantoin(Bochers,1977).Xanthine,hypoxanthineanduricacidwere convertedtoallantoinusingtheenzymeprocedureofFujiharaetal.(1987).Microbialprotein (MP)supplytothesmallintestinewascalculatedfromtheu rinaryoutputofPDusingthe equationofChenetal.(1992). VolatilefattyacidsinruminalfluidweremeasuredusingthemethodofCanaleetal. (1984)andaHighPerformanceLiquidChromatograph(Hitachi,FL7485,Tokyo,Japan) coupledtoaUVDetecto r(Spectroflow757,ABIAnalyticalKratosDivision,Ramsey,NJ)setat 210nm.ThecolumnusedwasaBio RadAminexHPX 87H(Bio Radlaboratories,Hercules, CA)with0.015MH 2 SO 4 mobilephaseandaflowrateof0.7mL/minat45 o C .Ruminalfluid NH 3 Ncon centrationwasdeterminedbyanALPKEMautoanalyzer(ALPKEMCorporation, Clackamas,OR)andanadaptationoftheNoelandHambleton (1976)procedurethatinvolved colorimetricquantificationofN. Plasmaglucose(PGlu)andureaN(PUN)concentrationswere measuredusingadaptations foraTechniconAutoanalyzerII(Bran Luebbe,Elinsford,NY)andmethodsofGochmanand Schmidz(1972),andCoulombeandFavreau(1963). StatisticalAnalyses DatawereanalyzedwithPROCMIXED(SASInst.Inc.,Cary,NC).Themo delfor analyzingchemicalcompositionofforageincludedforagespeciesandperiod(randomvariable). Themodelforanalyzingintake,digestibility,Nexcretionandretention,MPparameters,PUN andPGluincludeddietarytreatment,period,dietarytreatm entperiod,andlamb(random variable) .ThemodelforanalyzingruminalfluidpH,NH 3 NandVFAincludeddietary

PAGE 66

66 treatment,timeofcollection(repeatedmeasure),dietarytreatmenttimeofcollection,andlamb (randomvariable).Meanswereseparated withaPDIFFstatement.Significancewasdeclaredat P <0.05andtendenciesat P >0.05and 0.10. Results ForageChemicalComposition Drymatterconcentrationswerenotdifferentamongforages,butOMconcentrationwas greaterinallotherhaysthaninperennialpeanuthay(Table4 1).Asexpected,CPconcentration waslowest( P <0 .01)inbahiagrasshay.Amonglegumes,CPconcentrationsweregreaterin annualandperennialpeanuthaysthanincowpeaandpigeonpeahays.Neutraldetergentfiber concentrationwasgreatest( P <0.01)inpigeonpeahayfollowedbybahiagrasshay,andlo west inannualandperennialpeanuthays.Thegreatest( P <0.01)ADFconcentrationwasin pigeonpeahayandthelowest( P <0.01)concentrationwasinperennialpeanuthay.Lignin concentrationwasgreater( P <0.10)inpigeonpeahaythantheotherhays .Invitrotrue digestibilitywasgreatest( P <0.01)inperennialpeanuthayfollowedbyannualpeanuthay. Bahiagrasshaycontainedlower( P <0.01)IVTDthanalllegumesexceptpigeonpeahaywhich containedthelowest( P <0.01)IVTD.Condensedtanni nconcentrationswerelowinallforages. ExtractableCTconcentrationwasgreatest( P <0.01)inperennialpeanuthayfollowedby cowpeahay.BoundCTconcentrationwasgreatest( P <0.01)inperennialandannualpeanut haysfollowedbypigeonpeahay. IntakeandDigestibility Withtheexceptionofpigeonpeahay,legumehaysupplementationincreasedintakeof DM,OM,andNDF(Table4 2).IntakesofDM,OM,andNDFweregreatest( P <0.01)in lambssupplementedwithperennialpeanuthay,followedbyann ualpeanuthay,andtheywere lowerinlambsconsumingbahiagrasshayaloneorpigeonpeahaythanthoseconsumingother

PAGE 67

67 legumehays.IntakesofDM,OM,andNDFwerenotimprovedbyadditionofsoybeanmeal. DigestibilitiesofDMandOMweregreatestwhen dietsweresupplementedwithperennial peanuthay,followedbyannualpeanuthay.Additionoftheothersupplementsdidnotaffect Item Bahia Annual peanut Perennial peanut Cowpea Pigeonpea Soybean SEM 1 DM,% 91.1 91.0 90.8 91.5 91.8 91.6 1.8 OM,%D M 94.5 a 92.4 b 90.8 c 92.6 b 94.7 a 93.8 ab 0.5 CP,%DM 8.1 d 14.7 ab 15.2 a 11.7 c 12.2 c 13.5 b 0.4 NDF,%DM 73.8 b 46.2 e 43.3 f 62.2 c 78.6 a 59.0 d 1.0 ADF,%DM 39.8 cd 37.8 d 32.1 e 48.7 b 60.2 a 42.8 c 1.3 Lignin,%DM 6.2 b 7.9 b 6.7 b 9.5 b 17.1 a 9.6 b 1.1 IVTD,% 50 .7 d 71.4 b 77.2 a 57.9 c 35.1 e 57.4 c 1.1 ExtCT 2 ,%DM 0.12 cd 0.16 cd 1.56 a 0.56 b 0.26 c 0.05 d 0.07 BoundCT 3 ,%DM 0.34 cd 2.52 a 2.26 a 0.57 c 0.87 b 0.15 d 0.11 digestibilityofDMorOMexceptthatfeedingpigeonpeahayreducedOMdigestibility. Digest ibilityofNDFwasgreaterinlambsfedbahiagrasshayalone,soybeanmealorperennial peanuthaythaninlambssupplementedwithcowpeahay. NitrogenUtilizationandPlasmaMetabolites Nitrogenintakewasincreased( P <0.01)bysupplementationregardl essofsupplement typeanditwasgreatest( P <0.01)inlambsfedperennialpeanuthay,followedby( P <0.01) annualpeanuthay(Table4 3).FecalNoutputwasgreatest( P <0.01)inlambsfedperennial peanuthay,followedbyannualpeanutandsoybean hays,anditwaslowestinlambsfed bahiagrasshayalone,soybeanmealorpigeonpeahay.UrinaryNexcretionwasgreaterinlambs Table4 1 Chemicalcompositionandinvitrotruedigestibility(IVTD)ofh ays 1 SEMvaluesreflectthevariationofsamplescollecteddailyandcompositedwithin period(n=2). 2 Extr actablecondensedtannin(ExtCT) 3 Boundcondensedtannin( BoundCT) Withinarowmeanswithoutacommonsuperscriptletterdiffer( P <0.05).

PAGE 68

6 8 Table4 2.Intakeandapparentdigestibility(DMbasis)oflambsfedbahiagrasshaysupplementedwith warm seasonlegum ehaysorsoybeanmeal(SBM) Item Bahia SBM Annual peanut Perennial peanut Cowpea Pigeonpea Soybean SEM Totalintake,g/d DM 665 ef 726 de 975 b 1105 a 803 cd 612 f 864 c 29.2 OM 629 ef 685 de 911 b 1034 a 752 cd 579 f 811 c 27.6 NDF 500 e 522 de 594 b 654 a 558 cd 468 e 583 c 19.4 Digestibility,% DM 58.5 cd 60.3 c 64.3 b 67.8 a 58.8 cd 56.3 d 60.7 c 0.9 OM 60.6 c 61.4 c 65.4 b 68.7 a 59.7 cd 57.5 d 61.7 c 1.0 NDF 60.8 abc 60.8 abc 57.9 cd 62.2 a 56.6 d 58.7 bcd 58.9 bcd 1.0 Withinarowmeanswithoutacommonsuperscriptletterdiffer( P <0.05).

PAGE 69

69Table4-3.Nitrogenbalance,microbialNsynthesis,apparentlydigestedOM(DOM),andbloodmetabolitesoflambsfedbahiagrasssupplementedwithwarm-seasonlegumehaysorsoybeanmeal(SBM)MeasurementBahiaSBMAnnualpeanutPerennialpeanutCowpeaPigeonpeaSoybeanSEM Nitrogenintake,g/d8.8e15.6c17.7b21.3a12.9d11.8d15.6c0.54 FecalNoutput,g/d4.8d5.1d6.5b7.3a5.8c5.2d6.4b0.20UrinaryNoutput,g/d2.1c2.7b4.3a3.6ab2.5c2.6c4.0a0.35RetainedN,g/d2.0d4.2c7.0b10.5a4.6c4.1c5.1c0.54Ndigestibility,%46.5 e 56.8 cd 62.4 b 66.8 a 54.0 d 55.6 cd 58.1 c 1.1PD 1 output,mmol/d7.4 bc 6.3 c 10.1 a 11.0 a 6.2 c 7.2 c 9.7 ab 1.05MicrobialN,gN/d6.4bc5.5c8.7a9.5a5.4c6.2c8.4ab0.91DOM,g/d385e437de587b681a469cd336f500c21.5Microbialefficiency,gmicrobialN/kgDOM16.512.815.113.211.918.417.02.30PUN2,mg/dL12.5abc8.3c13.5a13.2ab11.0bc10.1c10.8bc0.98PGlu3,mg/dL70.1b73.7ab74.0ab76.8a72.3b70.2b72.5b1.41 1 Urinarypurinederivatives2Plasmaureanitrogen3Plasmaglucose Withinarowmeanswithoutacommonsuperscriptletterdiffer( P <0.05).

PAGE 70

70 fedperennialandannualpeanutorsoybeanhaysthaninthosefedbahiagr assalone,cowpeaor pigeonpeahays.Nitrogenretentionanddigestibilitywereincreasedbysupplementationandthe greatest( P <0.01)valuesoccurredinlambsfedperennialpeanut,followedbyannualpeanut. PurinederivativeexcretionandmicrobialN productionweregreaterinlambsfedperennialand annualpeanuthaysthanthosefedallotherdietsexceptsoybeanhay.ApparentlydigestibleOM intakewasgreatest( P <0.01)inlambsfedperennialpeanuthay,followedbyannualpeanuthay. Microbiale fficiencywasnotaffectedbysupplementation.PlasmaureaNconcentrationwas greater( P <0.01)inlambsfedannualpeanutthaninthosefedcowpea,pigeonpea,orsoybean haysorsoybeanmeal.Plasmaglucoseconcentrationwasgreaterinlambssupplemen tedwith perennialpeanuthaythanthosefedbahiagrassaloneorpigeonpea,cowpeaorsoybeanhays. RuminalFluidpH,NH 3 NandVFA RuminalpHwasnotdifferentamongdietarytreatments(Table4 4).Ammonia N concentrationwasgreaterinruminalfluidof lambsfedannualandperennialpeanutandcowpea hays,thanthosefedbahiagrassaloneorsoybeanmeal.TotalVFAconcentrationandproportions ofmostindividualVFAwerenotdifferentamongdietarytreatments.Propionatemolar percentagewasgreaterin ruminalfluidoflambsfedbahiagrasshayversusthosesupplemented withlegumes.Iso valerateconcentrationwasgreaterinruminalfluidoflambsfedperennial peanutthanthosefedallotherdietsexceptannualpeanuthay.Acetate:propionateratiowas greaterinruminalfluidoflambssupplementedwithperennialpeanut,cowpea,pigeonpea,and soybeanhayorsoybeanmealthanthosefedbahiagrassaloneorannualpeanuthay. Discussion Thenutritivevalueofthebahiagrasshaywassimilartothatrepor tedforbahiagrasshay harvestedatthesamematurity(Kostenbauderetal.,2007).TheNDF,ADF,andCP concentrationsofperennialpeanutweresimilartothosereportedfortheFlorigrazecultivarwhen

PAGE 71

7 1 Table4 4.RuminalfluidpH,NH 3 NandVFAconcent rationsoflambsfedbahiagrasshaysupplementedwith warm seasonlegumehaysorsoybeanmeal(SBM) Measurement Bahia SBM Annual peanut Perennial peanut Cowpea Pigeonpea Soybean SEM RuminalpH 7.1 7.1 7.0 7.1 7.1 6.9 7.0 0.05 AmmoniaN, mg/dL 2.5 c 3.7 bc 6.6 a 7.0 a 6.1 a 5.5 ab 5.5 ab 0.7 TotalVFA,mmol/L 112.0 114.8 121.6 125.7 107.2 105.1 110.8 6.2 Acetate,mol/100mol 57.1 56.6 57.0 55.5 58.1 58.9 58.4 0.8 Propionate,mol/100mol 2 3.9 a 23.3 ab 21.9 b 21.2 c 21.1 c 20.7 c 20.0 c 0.6 Iso butyrate,mol/100mol 2.0 3.0 3.4 3.8 4.7 3.9 3.9 0.6 Butyrate,mol/100mol 10.8 11.1 10.9 11.6 10.9 10.4 11.8 0.5 Iso valerate,mol/100mol 4.8 b 4.8 b 5. 4 ab 6.8 a 4.5 b 5.2 b 4.3 b 0.5 Valerate,mol/100mol 1.7 1.6 1.5 1.3 1.0 1.1 1.7 0.4 Acetate:propionate 2.4 c 2.5 bc 2.4 c 2.6 ab 2.8 ab 2.7 ab 3.0 a 0.1 Withinarowmeanswithoutacommonsuperscriptletterdiffer( P <0.05)

PAGE 72

72 harvestedatthesamematurityandstubbleheight(Romeroetal.,1987).Althought heCP concentrationofcowpeawassimilartothatreportedforIronclaycowpeagrowninFlorida (Higueraetal.,2001),theNDF,ADFandADLconcentrationswerealmosttwiceasgreatas thoseofIronclaycowpeaharvestedatanearliermaturitystage(ca nopyclose)byMuiretal. (2001).TheCPconcentrationandIVTDofpigeonpeaweremuchlowerthanthosereported (20%and49 55%IVDMDrespectively)forsimilarearly maturingcultivarsthatwereharvested earlier(50%flowering)andcutatagreaterstu bbleheight(0.6m;Alexanderetal.,2007).The NDFandADFconcentrationsofsoybeanweregreaterthanthosereportedforsimilarcultivars bySeiteretal.(2004),butCPconcentrationsweresimilar. PerennialandannualpeanutshadgreaterIVTDthano therlegumesduetotheirlowerNDF andADFconcentrations.Althoughthevalueswerenotidentical,therankingofforagesby IVTDwasthesameasthatbyinvivoapparentDMdigestibility,indicatingthattheIVTD methodissuitableforcomparingthesew arm seasonlegumes.Allforagescontainedlow concentrationsofCT.Condensedtanninsnegativelyimpactforagequalityatconcentrationsof 6%ofDMorgreater(Waghornetal.,1994),butconcentrationsof2to4%ofDMhave improvedforagenutrientutil izationbyruminants(Minetal.,2003;2005).Condensedtannin concentrationswereconsistentwiththosereportedpreviouslyforcowpea(Baloyietal.,2001), pigeonpea(Alexanderetal.,2007),perennialpeanut(Valenciaetal.,2007),annualpeanut (Ka rchesyandHemingway,1986),andsoybean(Reddyetal.,1985)forages.Thatbahiagrass had0.4%totaltanninisnotunusual,becausemanysubtropicalandtropicalgrassescontainsmall amountsoftannin(Jacksonetal.,1996;Gatesetal.,2004). Legume scontainedlessCPthananticipatedbasedonconcentrationsofthestandingplants (Chapter3).Thismaybebecauseofleafshatterduringharvestandchopping.Nevertheless,

PAGE 73

73 supplementationwithalllegumes,exceptpigeonpea,increasedDMandOMintake thoughonly annualandperennialpeanuthaysalsoincreasedDMandOMdigestibility.Theseintake responsestypifyeffectsoflegumesupplementationtopoorqualitybasalgrassdiets(Saidand Tolera,1993).Theyarelikelyduetoincreasedrateofpass age,whichistheprimaryfactor affectingintakeinruminants(Bowmanetal.,1991)becauselegumeshavefasterratesofpassage thangrasses(JungandAllen,1995).Thereticulatevenationoflegumeleavesrelativetothe parallelvenationofgrassleav es(Frame,2005)andthelowerstructuralcarbohydrate concentrationoflegumes(Wilson,1994)increasestherateofparticlesizereductioninlegumes versusgrassesduringmasticationandmicrobialdegradation.Consequently,legumeparticles flowoutof therumenatfasterrates(Waghornetal.,1989;Dewhurstetal.,2003a).Relative differencesinDMintakeanddigestibilityamonglegumesreflecttheirstructuralfiber concentrationsandmorphologicalcharacteristics.Unliketheotherlegumes,annual and perennialpeanutareprostrate,spreadingplantswithrelativelyhighleaf to stemratios,therefore theyhavelowconcentrationsofNDFandADF,andconsequently,theyaremoredigestiblethan theotherlegumes.PigeonpeahadhigherNDFandADFconc entrationsbecauseofitsthick, woodystems,whichprobablyincreasedgutfill,therebydecreasingintake.ThegreaterADL concentrationofpigeonpeaexplainsitslowerdigestibility.GreaterADFandADL concentrationsinpigeonpeaversusbahiagrasshay alsoexplainwhysupplementationwith pigeonpeadecreasedDMandOMintakeandOMdigestibility.Asinotherstudies(MirandMir, 1993:Haddad,2000;Mupwangaetal.,2000a),legumesupplementationdidnotincreaseNDF digestibilitypartlybecauselegum esgenerallyhavemoreligninthangrasses(Wilson,1994). LegumehaysupplementationincreasedNintakebecauseofthegreaterCPconcentrations ofthelegumesversusbahiagrass,aswellasthegreaterDMintakeofmostofthelegume grass

PAGE 74

74 diets.Nitro genretentionincreasedaccordinglybecausesupplementationincreasedN digestibilityanddecreasedtheproportionofintakeNlostasurine(21.4%versus23.9%).These reasonsalsoexplainwhyNretentionwasgreaterinlambsfedperennialpeanutthanth osefed otherlegumes.LegumesupplementationresultedingreaterruminalNH 3 Nconcentrations becauseitincreasedNintakeandmostoftheproteininlegumesisintheformofsolubleprotein orRDP(Broderick,1995).Legumesupplementationwasnecessa rytoensurethatruminalNH 3 Nconcentrationsexceededtherecommendedconcentration(5.0mg/dL;SatterandSlyter,1974) formaximizingmicrobialNsynthesis.Nevertheless,microbialNsynthesiswasonlyincreased bysupplementationwithannualorperen nialpeanuthays.Thiswaspartlybecauseannualand perennialpeanuthaysupplementsresultedinthegreatestdigestibleOMintakesandmicrobialN synthesisisdirectlycorrelatedwithdigestibleOMintake(Clarketal.,1992).Greaterdigestible OMin takeinthesedietsisattributabletothelowconcentrationofstructuralfibercomponents thatimpededigestionandintakeinannualandperennialpeanuts.Soybeanmeal supplementationincreasedNintakeandretentionbecauseofthehighNconcentration of soybeanmeal.However,thesmallamountofsoybeanmealthatwasfedwasnotsufficientto improveothermeasuresofperformance. ThetotalVFAconcentrationandmolarproportionofVFAweretypicaloftheruminal fluidofruminantsfedaforage bas edration(Bergman,1990).Thedecreaseinruminal propionateproportionandtheattendantincreaseinacetate:propionateratioofmostlegumediets suggeststhattheyreducedtheefficiencyofruminalfermentation.Thegreaterrateofpassageof legume supplementeddietsmayhavecontributedtothedecreaseintheruminalpropionate proportion(Harrisonetal.,1975;1976).

PAGE 75

75 TheconcentrationsofPUNandPGluwerewithinphysiologicallynormalranges(8to20 and50to80mg/dL,respectively;Kenako,198 9)suggestingadequateintake,degradation,and absorptionofproteinandenergyfromthesediets.Thefactthatlegumesupplementation increasedruminalNH 3 NconcentrationbutnotPUN,suggeststhattheammoniawaseither incorporatedintomicrobialcel lsorexcreted. SupplementationwithNfromlegumehaysorsoybeanmealincreasedNintake,digestion andretention,indicatingthatsupplementationisnecessaryforoptimizingtheutilizationof bahiagrassinlambs.AtthemoderatedietaryCPconcentra tionevaluated,annualandperennial peanuthaysupplementationwasmoreeffectivethansoybeanmealsupplementationat improvingintakeandmicrobialNproduction.Perennialpeanutandannualpeanutwerethe mostpromisinglegumesupplementsbecausethey resultedinthegreatestDMandOMintakes anddigestibilitiesandthegreatestNintake,Ndigestibility,Nretention,andmicrobialN synthesis.Soybeanandcowpeahayswerealsopromisingsupplementsforimprovingruminant livestockproductionbecause theyincreasedDMandOMintake,Nintake,Ndigestibility,andN retention.PigeonpeahaysupplementationincreasedNintake,Ndigestibility,andNretention butdidnotimproveDMorOMintakesandreducedOMdigestibility;therefore,itwastheleast desirablesupplement.Pigeonpeashouldbeharvestedathigherstubbleheightsforuseasa legumesupplement,butthiswouldreducebiomassyields.Futureresearchshoulddeterminethe optimalinclusionratesoftheselegumehaysinbahiagrassbasalrat ionsandanalyzethe economicsoffeedinglegumehaysinsteadofconcentrateproteinsupplements.

PAGE 76

76 CHAPTER5 NUTRITIVEVALUEAND FERMENTATIONCHARACT ERISTICSOFENSILED WARM SEASONLEGUMESANDB AHIAGRASS Introduction Conservingforagesassilageorhaylageisacommonpracticethatensuresavailabilityof highqualityforageforwinterfeedingofrumin antlivestock,andfacilitatesyear roundhousing ofdairycows.Ensilingisanimportantalternativeforagestoragemethodwhenenvironmental conditionshinderstorageofhay,especiallyinclimateswithrainfallduringtheseasonofharvest andstorage ( AlbrechtandBeauchemin,2003) .Ideally,silageisproducedbyrapidanaerobic fermentationofplantsugarswithlittlechangeintheCPandfiberconcentrationoftheforage ensiled(Muck,1988).Cool seasongrasseshavegreaterwater solublecarbohydr ate(WSC) concentrationthanlegumessuchthatduringfermentation,theirpHdropsrapidlyandproteolysis islimited( Contreras Goveaetal.,2006 ).Incomparison,legumeshavegreaterCP concentration,lowerWSCconcentration,andgreaterbufferingcapa city,whichcollectively makelegumesmoresusceptibletoproteolysis(Contreras Goveaetal.,2006).Nevertheless, alfalfa( Medicagosativa L.)silageandseveralensiledclover( Trifolium spp.)speciesarewidely usedinruminantlivestockrationsbecau seoftheirrelativelyhighCPconcentrations.However, informationabouttheensilingcharacteristicsandnutritivevalueofwarm seasonlegumesis limited.Perennialpeanut( Arachisglabrata Benth.)isawarm seasonlegumethathas comparablenutritive valuetoalfalfaandiswidelygrowninFloridaandGeorgiawherealfalfais notadapted(NewmanandChambliss,2003;Frenchetal.,2006).Perennialpeanutsilage replaced70%ofcornsilageinadairycowrationcontaining50%ofconcentratewithout af fectingmilkproduction(Staplesetal.,1997).However,perennialpeanutissprigplantedand ittakes1to2yrforestablishmentofagoodstand.Consequently,establishingperennialpeanut isoftenmoreexpensivethanotherforagecrops(Frenchetal .,2006).Seededwarm season

PAGE 77

77 legumesareeasierandcheapertoplantandtheycanbeestablishedfaster,buttheyonlypersist foroneseason.Annualpeanut( Arachishypogaea L.)isaseededwarm seasonlegumethathas beensuccessfullyensiled.Annual peanutsilageincreasedDMintakewhenitreplaced50%ofa 100%cornsilagedietfedtonon lactatingheifers(Johnsonetal.,1979).Asearlyas1896, cowpea( Vignaunguiculata (L.)Walp.)wasstudiedforuseasgrazedforage,hayorsilage. Hopkins(1 896)foundthatcowpeasilagewas7%moredigestiblethancloversilagewhenfedto sheepandasdigestibleascornsilagewhenfedtocattle,butlittleisknownabouttheensiling potentialofcurrentcultivars.Cowpeaisoftenensiledwithforagessuch aspearlmillet ( Pennisetumglaucum (L.)R.Br.),sorghum( Sorghumbicolor (L.)Moench),orsudangrass ( Sorghumsudanense (Piper)Stapf)toincreasetheWSCconcentrationandimprovethe fermentationofcowpea(McCulloughetal.,1960;BishnoiandMentre ddy,2004),butno publishedinformationonensiledmonoculturesofcowpeawasfound.Pigeonpea( Cajanuscajan (L.)Millsp.)isarelativelynewforageintheUnitedStates(Raoetal.,2002;2003),whichhas shownpotentialasaforageforgrazingorhay orsilageproductioninothercountries(Otero, 1952)buttoourknowledgeithasnotbeenensiledintheUnitedStates.Thepurposeofthis studywastodeterminethefermentationcharacteristics,nutritivevalue,andaerobicstabilityof bahiagrass( Pa spalumnotatum Flgge cv.Tifton9),perennialpeanut(cv.Florigraze),annual peanut(cv. FLMDR98),cowpea( cv. Ironclay) ,andpigeonpea( cv. Georgiatwo). Bahiagrass wasalsoevaluatedbecauseitisthemainpastureforageinthesoutheastanditwou ldbefedwith thelegumes. MaterialsandMethods ForageProduction LegumeswereproducedattheNorthFloridaResearchandEducationCenterinMarianna, FL(31N).SoilontheexperimentsitewasChipolaloamysand(loamy,kaolinitic,thermic,

PAGE 78

78 ArenicKa nhapludults)andOrangeburgloamysand(fine loamy,kaolinitic,thermic,Typic Kandiudults).Topreparethefieldforplantingcowpea,lime(2,250kg/hacalciticlime)and310 kg/hafertilizer(0 18 10 10ratioofN:P 2 O 5 :K 2 O:S)wereappliedandthefield wasplowed.To prepareforplantingpigeonpea,1,120kg/hadolomiteand300kg/hafertilizer(5 25 26ratioof N:P 2 O 5 :K 2 O)wereappliedandthefieldwasplowed.Cowpeaandpigeonpeawereinoculated with Bradyr hizobium spp.(BeckerUnderwood,Inc.,Royal Peat,Ames,IA)andseededatarate of56kg/ha.Cowpeawasdrilledat15 cmrowspacingonfour0.405 haplotswhereas pigeonpeawasdrilledat66 cmrowspacingonasingle2 haplot.Thelegumeswereplantedin Mayandharvestedattherecommendedm aturitystagethatmaximizesbothDMyieldand nutritivevalue.Cowpeawasharvestedwhenpodsbegantoturnyellow(NDA,1997)and pigeonpeaatpodsetting(Hourou,2006).Establishedstandsofperennial(5 yr old)andannual peanut(7 yr oldwithself reseeding)wereharvestedasfirstcuttings.Cowpea,perennialand annualpeanutwerecuttoastubbleheightof10cm,whereaspigeonpeawascutatthemaximum stubbleheightallowedbythecutterbar(40cm).Itisrecommendedtoharvestthetop66to 75% ofpigeonpeatomaximizenutritivevalueandfacilitatedrying(Hourou,2006).Bahiagrass(cv. Tifton9)wasfromanestablishedstand (7 yr old) andthefieldwasfertilizedwith390kg/haof 17 17 17ratioofN:P 2 O 5 :K 2 Oinlatespring.Aftereach cutting,thebahiagrasswastopdressed with280kg/haoffertilizer(30 0 0 0.6ratioofN:P 2 O 5 :K 2 O:S),andthethirdcutting,takenafter 5 wkofregrowthwasusedinthisexperiment.Legumesandbahiagrasswereharvestedusinga mowerconditioner(New Holland,Haybinemodel474,NewHollandAgriculture,NewHolland, PA).Afterwiltingto45%DM,small(140kg)roundbalesweremadeusingaVermeer504L baler(VermeerManufacturingInc.,Pella,IA).Baleswerewrapped4timesallowing50% overlapwit harollofwhitepolyethyleneplastic(1mm)usingaKvernelandwrapper

PAGE 79

79 (KvernelandNorthAmerica,model7510,EastSyracuse,NY).Eightbalesofbahiagrassand4 balesofeachlegumewereensiledforatleast180d. ChemicalAnalyses Triplicatesample sofeachforageweretakenfromrepresentativepartsoftherespective fieldsatcutting.Aftereachbalewasopened,theforagewasthoroughlymixed,and representativesub samplesweretakenforanalysisofmicrobialcounts(200g)andaerobic stabilit y(800g).Additionalrepresentativesamplestakenfordeterminationofchemical composition(1kg)andfermentationindices(200g)werefrozen( 20C)untilanalysis. HaylageextractpHwasdeterminedbymixing20gofhaylageinablenderwith200mLo f distilledwaterfor30sathighspeed.Themixturewasfilteredthroughtwolayersofcheesecloth andthepHwasimmediatelymeasuredusingapHmeter(Accumet,modelHP 71,Fischer Scientific,Pittsburg,PA).Thefiltratewascentrifugedat1369 g for20minat4 o Candthe supernatantwasstored( 20 o C )untilfurtheranalysisofVFAandNH 3 N. Samplesreservedformicrobialanalysiswereheat sealedwithingas impermeablebags (Kapak/ScotchPak,KapakCorp.,Minneapolis,MN),placedinacooleran dtransportedonthe samedtotheAmericanBacteriological&ChemicalResearchCorporationinGainesville, Florida.YeastsandmoldswereenumeratedbypourplatinginStandardMethods(M124)agar, towhich4%ofchloramphenicolandchlortetracyclinewer eadded(Tournasetal.,1999). Aerobicstabilitywasmeasuredbyplacingthermocouplewiresatthecenterofabag containing800gofhaylagewithinanopen toppolystyreneboxcoveredwithtwolayersof cheeseclothtopreventdrying.Thethermocouplew ireswereconnectedtodataloggers (CampbellScientificInc.NorthLogan,UT)thatrecordedthetemperatureevery30minfor21d. Aerobicstabilitywasdenotedbythetimethatelapsedpriortoa2Criseinsilagetemperature aboveambienttemperature (18to25 o C).

PAGE 80

80 Samplesofforagetakenbeforeandafterensilingwereweighedanddriedat60 o Cfor48h forDMdetermination.Driedsamplesweregroundtopassthrougha1 mmscreeninaWiley mill(ArthurH.ThomasCompany,Philadelphia,PA).Sampleswe reanalyzedforashby combustioninamufflefurnaceat600 o Covernight.TotalNwasdeterminedbyrapid combustionusingamacroelementalNanalyzer(Elementar,varioMAXCN,Elementar Americas,MountLaurel,NJ)andusedtocomputeCP(CP=N6.25). Neutraldetergentfiber concentrationwasmeasuredusingthemethodofVanSoestetal.(1991)inanANKOM200 FiberAnalyzer(ANKOMTechnologies,Macedon,NY).Amylasewasusedintheanalysisand theresultswereexpressedonaDMbasis.TheANKOM(2 005a)adaptationoftheVanSoestet al.(1966)methodforanANKOMDaisy II Incubator (ANKOMTechnology,Macedon,NY) and theANKOM200FiberAnalyzerwasusedtodetermineinvitrotruedigestibility(IVTD). An adaptationoft heNoelandHambleton(1976) procedure thatinvolvedcolorimetricquantification ofN wasusedtodetermineNH 3 NwithanALPKEMautoanalyzer(ALPKEMCorporation, Clackamas,OR).VolatilefattyacidsweremeasuredusingthemethodofCanaleetal.(1984) andaHighPerformanceLiqu idChromatograph(Hitachi,FL7485,Tokyo,Japan)coupledtoa UVDetector(Spectroflow757,ABIAnalyticalKratosDivision,Ramsey,NJ)setat210nm. ThecolumnwasaBio RadAminexHPX 87H(Bio Radlaboratories,Hercules,CA9454)with 0.015MH 2 SO 4 mob ilephaseandaflowrateof0.7mLat45 o C StatisticalAnalyses Theexperimenthadacompletelyrandomizeddesignwith5treatmentsand4replicatesof eachlegumeforageandeightreplicatesofbahiagrass.Foragespecieswasincludedinthemodel and datawereanalyzedwiththeMIXEDprocedure(SASInst.Inc.,Cary,NC).Whentheforage specieseffectwassignificant( P >0.05)meanswereseparatedwithaPDIFFstatement. Tendenciesweredeclaredat P >0.05and 0.10.

PAGE 81

81 Results ChemicalCompositionofPre ensiledForages Amongpre ensiledforages,DMconcentrationwasgreatest( P <0.01)inannualpeanut, followedbypigeonpea,andlowest( P <0.01)incowpea(Table5 1).Organicmatter concentration wasgreatestinpigeonpea,followedbybahiagrass,andannualandperennial peanuthadthelowestvalue.Crudeproteinconcentrationwasgreaterinlegumesthan bahiagrass.Incontrast,NDFconcentrationwasgreaterinbahiagrassthanlegumes.Among leg umes,CPconcentrationsofannualandperennialpeanutweregreaterthanthatinpigeonpea, whichhadthegreatest( P <0.01)NDFconcentration.Annualandperennialpeanutandcowpea hadgreater( P <0.01)IVTDthanpigeonpeaandbahiagrass. Item Bahia grass Annual peanut Perennial peanut Cowpea Pigeonpea SEM DM,% 26.7 c 37.2 a 24.6 c 16.4 d 29.6 b 0.8 OM,%DM 94.2 b 91.4 d 90.9 d 92.4 c 95.3 a 0.4 CP,%DM 10.9 c 18.9 a 18.5 a 16.6 ab 13.9 b 0.9 NDF,%DM 68.0 a 40.0 c 38.3 c 39.6 c 59.3 b 1.8 IVTD,% 59.7 b 80.5 a 7 9.3 a 80.6 a 55.4 b 4.9 Item Bahiagrass Annual peanut Perennial peanut Cowpea Pigeonpea SEM DM,% 51.7 55.7 49.7 52.9 46.9 2.3 OM,%DM 93.5 93.2 92.6 92.6 95.0 1.2 CP,%DM 8.8 d 18.9 a 15.8 b 15.5 b 13.2 c 0.8 NDF,%DM 70.9 a 42.8 c 40.8 c 45.5 c 65.2 b 2 .3 IVTD,% 58.6 b 74.1 a 74.5 a 71.3 a 45.4 c 3.9 Table5 2. Haylagechemicalcomp ositionandinvitrotruedigestibility Withinarowmeanswithoutacommonsuperscriptletterdiffer( P <0.05). Table5 1.Chemicalcomposition andinvitrotruedigestibility offoragesbefore wilting and ensiling Withinarowmeanswithoutacommonsuperscriptletterdiffer( P <0.05).

PAGE 82

82ChemicalCompositionofHaylagesTheDMandOMconcentrationswerenotdifferentamonghaylages(Figure5-2).Legumescontainedgreater(P<0.01)CPconcentrationsthanbahiagrass,andamonglegumes,CPconcentrationwasgreatestinannualpeanutandlowestinpigeonpea.Bahiagrassandpigeonpeahadgreater(P<0.01)NDFconcentrationsthantheotherhaylages.AnnualandperennialpeanutandcowpeahadthegreatestIVTD,whereaspigeonpeahadthelowestvalue(P<0.01).ItemBahiagrassAnnualpeanutPerennialpeanutCowpeaPigeonpeaSEM pH5.11b5.18ab4.60c4.82bc5.43a0.14 NH3-N,%totalN11.5923.3317.6322.9818.213.30Lactate,%DM0.45b1.82a1.02b1.26ab0.50b0.35Acetate,%DM0.43c1.26a0.68bc1.72a1.11ab0.26Propionate,%DM0.020.060.00.080.00.03n-Butyrate,%DM0.01c0.87a0.77ab0.51abc0.34bc0.25TotalVFA,%DM0.52b2.19a1.45a2.32a1.40ab0.43Lactate:acetate1.06abc1.45ab1.56a0.73bc0.58c0.30 ItemBahiagrassAnnualpeanutPerennialpeanutCowpeaPigeonpeaSEM Yeasts,logcfu1/g2.92.82.62.43.01.0 Molds,logcfu/g2.53.22.43.53.50.6Aerobicstability,h280.1125.1130.6187.384.488.2 Table5-3.Fermentationcharacteristicsofbahiagrasshaylageandfourwarm-seasonlegumehaylagesTable5-4.Microbialcountsandaerobicstabilityofbahiagrasshaylageandwarm-seasonlegumehaylages 1 Colony-formingunitspergofhaylageWithinarowmeanswithoutacommonsuperscriptletterdiffer(P<0.05).Withinarowmeanswithoutacommonsuperscriptletterdiffer(P<0.05).

PAGE 83

83 FermentationIndices,MicrobialCountsandAerobicS tability NoneofthehaylageshadapHthatwaslessthan4.5,andpHwaslowerinperennial peanutandcowpeathaninbahiagrass(Table5 3).Ammonia Nconcentrationstendedtobe greater( P <0.06)inannualandperennialpeanutandcowpeahaylagesthan inbahiagrass haylage.Noiso valerate,valerateoriso buyratewasdetectedinthehaylages.Concentrations ofVFAandlactateweregenerallylowandlactateconcentrationwasgreaterinannualpeanut haylagethanthatinallotherhaylagesexceptcowp ea.Butyrateconcentrationwasgreater( P < 0.01)inannualandperennialpeanutthaninbahiagrass.TotalVFAconcentrationwasgreaterin annualandperennialpeanutandcowpeahaylagesthaninbahiagrasshaylage.Lactate:acetate ratiowaslowerinpi geonpeahaylagesthaninannualandperennialpeanuthaylages.Yeastand moldcountsandaerobicstabilitywerenotdifferent( P >0.10)amonghaylagesandallhaylages werestableforatleast84h(Table5 4). Discussion ChemicalComposition Publishe dinformationonthenutritivevalueofbahiagrasssilagewasnotfound. Bermudagrass( Cynodondactylon (L.)Pers.)isasimilarwarm seasongrass,andastudyby Batesetal.(1989)revealedthatensilingwilted(to45%DM)Coastcross 1andSuwaneein ro undbalesproducedasimilarreductioninCPconcentrationandasimilarincreaseinfiber concentrationtothoseinthisstudy.Thechemicalcompositionofthehaylagesapproximated respectivepublishedvaluesforbermudagrasshaylage(Batesetal.,1989 ;Ruizetal.,1995), annualpeanuthaylage(Johnsonetal.,1979),pigeonpeasilage(Franciaetal.,1993),and perennialpeanuthaylage(Batesetal.,1989)orsilage(Staplesetal.,1997).Published informationonthenutritivevalueofcowpeahaylage waslackingdespitetheexistenceofsuch dataformixedcowpea grassorcowpea cerealsilages.

PAGE 84

84 ThegreaterCPconcentrationandIVTD,andlowerNDFconcentrationoflegumesversus bahiagrassisconsistentwiththeliteratureonthenutritivevalueoft heseforages(Meissnerand Paulsmeier,1995).Unlikegrasses,legumeshaveasymbioticrelationshipwith Rhizobium and Bradyrhizobium bacteriathatallowsfixationofatmosphericN,leadingtoincreasedNinthe plant(Leepetal.,2002).Thelowerdiges tibilityofthebahiagrassinthisstudyispartlybecause photosyntheticcellsintheleaftissueofC 4 grassesarearrangedinKranzstructuresandoften containgirderstructures,whichcollectivelyincreasetheirNDFconcentrationanddecrease ruminal microbialdegradation,whereassimilaranatomicalfeaturesarelackinginC 3 legumes (Wilson,1994).Differencesinnutritivevalueamongthelegumesareattributabletotheir physiologicalandmorphologicaldifferences.PigeonpeahaylagehadlowerIVTD thantheother legumesbecauseofitslarge,woodystem(Masamaetal.,1997)andgreaterstructural carbohydrateconcentrationthantypicalforagelegumes. Whenforagesarewiltedandensiled,proteolysisoccurs(PetitandTremblay,1992) becauseofplant enzymaticactivityandmicrobialfermentationwhichexplainswhybahiagrass, perennialpeanutandcowpeahadlowerCPconcentrationsafterensiling.SimilarlossesofCP didnotoccurinannualpeanutandpigeonpeahaylagessuggestingthattheproteinin these forageswaslessdegradable.WiltingandensilingincreasedtheNDFconcentrationsofall foragesandtherebydecreasedtheirIVTDvalues,whichisprobablyduetomicrobialrespiration andfermentation.Sucheffectsweremorepronouncedincowpea andpigeonpeapartlybecause thewiltingperiodwasprolongedbythelowerinitialDMconcentrationofcowpeaandthick, woodystemsofpigeonpea. FermentationIndices,MicrobialCountsandAerobicStability ApHrangeof4.6to5.2isexpectedforlegum esilagesorhaylagesandarangeof4.4to 5.0isexpectedforgrassthatisensiledwhentheDMconcentrationisgreaterthan35%

PAGE 85

85 (McKersie,1983;HeinrichsandIshler,2000).Therefore,bahiagrassandpigeonpeahadhighpH values,buttheotherhaylage shadnormalvalues.Nevertheless,allhaylageshadpHvaluesthat exceededthelimit(4.0)forreducingproteolysisand Clostridial activity(Muck,1988). Consequently,allhaylageshadNH 3 Nconcentrationsabovethethresholdof10%oftotalN, whichs ignifiesminimalproteolysis.DuetotheirgreaterCPconcentrations,alllegumehaylages hadNH 3 Nconcentrationsabovethethreshold(15%oftotalN)signifyingmoderateproteolysis duetopoorfermentationor Clostridial secondaryfermentation(Seglar, 2003). Clostridial activityinlegumesilages wasconfirmedbytheirrelativelyhighconcentrationsofbutyrate. CharacteristicsofwellpreservedsilagesincludeapHatorbelow4.0,alactate:acetate ratioabove2.0(Owensetal.,1999),abutyrate concentrationbelow0.2%ofDM(Woolford, 1984),andanNH 3 Nconcentrationbelow10%oftotalN.Therefore,noneofthehaylageshad anidealfermentation.ThehighpHofthehaylagesisexplainedbytheirlowtotalVFA concentrations,whicharelikely attributabletolowWSCconcentrationandhighbuffering capacity(Umanaetal.,1991;Adesoganetal.,2004).Thelowlactateconcentrationsandlow lactate:acetateratiosindicatethepredominanceoflessefficientheterofermentativepathways duringen silingoftheforages(McDonaldetal.,1991). Yeastandmoldcountswerelowerthanthethreshold(5logcfu/g)atwhichsuch microorganismsincreaseaerobicstability(Seglar,2003),consequentlyalloftheforageswere relativelystable.Thelowyeas tandmoldcountsandrelativestabilityofthesehaylagesispartly becausethelowWSCoftropicalgrasses(Adesoganetal.,2004;Deanetal.,2005)andlegumes (Weinbergetal.,1993a;b;McAllisteretal.,1998)isnotconducivetogrowthofyeastsan d molds.Furthermore,thelowfungalcountsoflegumesarepartlyattributabletoappreciable butyrateconcentrationsbecausebutyratehasstrongantifungalproperties(Woolford,1975).

PAGE 86

86 Aerobicstabilityhasbeendemonstratedtoexceed384hinalfalfa( McAllisteretal.,1998)and 96hinbermudagrass(Adesoganetal.,2004). Unlikelegumes,thefermentationofbahiagrassdidnotculminateinappreciablebutyrate concentrationsorhighNH 3 Nconcentrations,indicatinglower Clostridial activity.Howev er, exceptforpigeonpea,legumehaylagesweremoredigestibleinvitrothanbahiagrasshaylage, andtheyhadgreaterCPconcentrations.Thereforethelegumehaylagescouldbeusedasenergy andproteinsupplementsforruminantlivestockfedbahiagrassha ylage.Annualandperennial peanutandcowpeahaylageswouldbebetterlegumesupplementsthanpigeonpeahaylage.Due totherelativelypoorfermentationofallthehaylages,furtherstudiesshouldcompareeffectsof addingbacterialorchemicaladditive sorfermentablecarbohydratesourcesonthefermentation oftheseforages.Experimentationtodetermineeffectsofensilingthelegumeswithcerealgrains orgrassesisalsorecommended.

PAGE 87

87 CHAPTER6 WARM SEASONLEGUMEHAYLAG EORSOYBEANMEALSU PPLEMENTATION EFFECTSONTHEPERFO RMANCEOFLAMBS Introduction Proteinsupplementationisoftennecessarytomeetnutrientrequirementsofruminant livestock .Legumesarecommonlyutilizedasprotein supplementsbecausetheirsymbiotic relationshipwithmicrobesthatfixatmosphericNincreasestheirCPconcentrations.Legumes alsoincreasesoilNstatusandthismaybeamoreeconomicalmethodofimprovingNinsoils thaninorganicfertilizerapplica tion (tMannetje,1997;PengellyandConway,2000),especially withtheincreasingfuel,andthusfertilizercosts.Alfalfa( Medicagosativa L. )isthemost commonlyusedlegumesupplementinruminantrationsintheUnitedStates.However,alfalfa doesn otpersistinsouthernstatesduetodiseases,insectsandnematodes(Prineetal.,1981). Sometropically adaptedwarm seasonlegumesthatmaybeimportantproteinsupplementsinthe Southeastincludeannualpeanut( Arachishypogaea L and pintoi Krapov. &W.C.Greg.) cowpea( Vignaunguiculata (L.)Walp. ),andperennialpeanut( Arachisglabrata Be nth ).Dueto inclementweatherduringharvestinsomesubtropicalandtropicallocations, thereis considerable interestin conserving theselegumesashaylag eratherthanhay,butonlyafew studiesonthefeedingvalueofensiledwarm seasonlegumesexist. Approximately10, 0 00haofperennialpeanutisgrowninFloridaandGeorgia,primarily forhay(Flores,2008).Eventhoughmilkproductionbydairycowsw asnotreducedby replacingdietarycorn( Zeamays )silagewithperennialpeanutsilage(Staplesetal.,1997), widespreaduseofperennialpeanuthasbeenhamperedbecauseitissprigplantedandslowto establish.Annualpeanut( A hypogaea L. )canbee stablished moreeasily becauseitisaseeded legume.Littleisknownaboutthenutritivevalueofannualpeanutsilagethoughonereport indicatesthatitwasmorereadilyconsumedbynon lactatingdairyheifersthancornsilage

PAGE 88

88 (Johnsonetal.,1979). Cowpeahasbeensuccessfullyensiledwithcorn, pearl millet( Pennisetum glaucum (L.)R.Br.) andsorghum( Sorghumbicolor (L.)Moench )inattemptstoimproveits fermentationcharacteristics(McCulloughetal.,1960;BishnoiandMentreddy,2004),but pub lishedinformationonthequalityofcowpeaforageensiledaloneislacking.Furthermore, littleisknownaboutthepotentialforusingwarm seasonlegumehaylagesasdietary supplementsforgrowing ruminantlivestock inthesoutheast.Thisstudywasaim edat determiningthefeedintake,digestibilityand N balanceoflambsfedbahiagrass( Paspalum notatum Flgge cv. Tifton9)haylagesupplementedwithsoybeanmealorhaylagesmadefrom eitherperennialpeanut( cv. Florigraze),annualpeanut( cv. FLMDR9 8),cowpea( cv. Ironclay) orpigeonpea( cv. Georgia two ). MaterialsandMethods ForageProductionandEnsiling LegumehaylageswereproducedattheNorthFloridaResearchandEducationCenterin Marianna,FL, (31N) onsoilsthatwerepredominatelyChi polaloamysand(loamy,kaolinitic, thermic,ArenicKanhapludults)andOrangeburgloamysand(fine loamy,kaolinitic,thermic, TypicKandiudults).Topreparethefieldforplantingcowpea,lime(2 250kg/hahigh callime) and 310 kg/hafertilizer(0 18 10 10ratioofN:P 2 O 5 :K 2 O:S)wereappliedandthefieldwas plowed.Beforeplantingpigeonpea, 1,120 kg/hadolomiteand 300 kg/hafertilizer(5 25 26ratio ofN:P 2 O 5 :K 2 O)wereappliedandthefieldwasplowed.Cowpeaandpigeonpeaseedswere inoculatedwit h Bradyrhizobium spp.(BeckerUnderwood,Inc.,RoyalPeat,Ames,IA)and cowpeawasdrilledat56kg/haand 15 cm rowspacingonfour 0.405 ha plots.Pigeonpeawas drilledat56kg/haand60 cmrowspacingona 2 ha plot.Bothseededlegumeswereplanted in MayandharvestedattherecommendedmaturityformaximizingDMyieldandnutritivevalue. Thiswas whenpodsbegantoturnyellowforcowpea (NDA,1997)andatpodsettingfor

PAGE 89

89 pigeonpea(Hourou,2006).Establishedstandsofperennial (5 yr old) and annualpeanut (7 yr old;selfreseeding) wereharvestedasfirstcuttingsinAugust2006.Anestablishedbahiagrass stand (7 yr old) wasfertilized(390kg/haof17 17 17ratioofN:P 2 O 5 :K 2 O)inearlyspring,top dressedwith 280 kg/haoffertilizer(30 0 0 0.6ratioofN:P 2 O 5 :K 2 O:S)aftereachcutting,and harvestedasthethirdcuttingafter5 wkofregrowth.Pigeonpeawascuttoastubbleheightof 40cmandallotherforageswerecuttoastubbleheightof10cmwithamowerconditioner (NewHolland, Haybinemodel474,NewHollandAgriculture,NewHolland,PA)basedon previousrecommendationsfortherespectiveforages(Romeroetal.,1987; Ortega S.etal., 1992 ;Hourou,2006).Windrowswerewiltedto45%DMandbaledintosmall(140kg)round bal esusingaVermeer504Lbaler(VermeerManufacturingInc.,Pella,IA).Baleswere wrappedwithasinglerollwrapper(Kvernelandmodel7510)with4layersof1 mmthickwhite polyethyleneplastic.BalesweretransportedtotheDepartmentofAnimalScien ces,Gainesville, FL,forthestudy. Animals,FeedingandHousing AllanimalprocedureswereapprovedbytheUniversityofFloridaInstitutionalAnimal CareandUseCommittee.Forty twoDorper Katadhin crossramlambsweighing27.55kg wereusedfo rtheexperiment.Beforetheexperiment alllambswerevaccinatedwitha 3 way enterotox e mia,coccidiosis,andtetanusvaccination(BarVacCD T,2 mL /head,Boehringer IngelheimVetmedicaInc.,St.Joseph,MO),de wormed(LevamasoleInjectable,2mL/45k g BW,AgriLabs,St.Joseph,MO),weighed,andtheirhoovesweretrimmed.Lambswere stratified byweightandrandomlyassignedto 6treatments(7 lambspertreatmentduringPeriod 1 and 4 lambspertreatmentduringPeriod2)inacompletelyrandomizedde signwith 2 periods. Eachperiodconsistedof14dofadaptationtodietsand7dofmeasurementandeachlamb receivedadifferentdietineachperiod.Lambswerefittedwithcanvasfecescollectionbagsand

PAGE 90

90 housedinindividualmetabolismcratesadapte dforcollectionoffecesandurine.Waterwas provided adlibitum and 20gofamineralpremix(UnitedSaltCorp.,RanchHouseTrace MineralizedSalt,Houston,TX)wasaddedtothedietofeachlambdaily.Themineralmix contained90%NaCl,3%Ca,1%S ,0.2%Fe,0.3%Mn,0.3%Zn,25mg/kgCo,150mg/kgCu, 90mg/kgI,and10mg/kgSe. Lambswerefed adlibitum (110%ofpreviousdaysintake)diets consistingofbahiagrasshaylagealoneorbahiagrasshaylagesupplemented(50%ofdietDM) withoneofthe legumehaylagesorwithsoybeanmealat8%ofdietDM. Thesoybeanmeal inclusionlevelwasaimedatmatchingtheaverageCPconcentration(12.8%DMbasis)ofthe legumediets. Thebahiagrassandrespectivesupplementswereofferedinthesametroughat 0800and1500. SampleCollection Samplesofeachfeedweretakendailyduringthe7dcollectionperiodanddailyrefusals wereweighedandstored.Totalfecaloutputwascollecteddailyfromeachlamb,weighed,anda 10%subsamplewasstored( 20 o C )fo rsubsequentanalysis.Thevolumeofdailyurineoutput wasrecordedfrom 6 lambspertreatmentinPeriod1andall 4 lambspertreatmentinPeriod2. Sulfuricacidwasaddedtosubsamples(10%)ofurinetoensurethatthepHremainedbelow3.0 andtheu rinewasstored( 20 o C )forfurtheranalysis.Lambswereweighedandbloodsampled byjugular venipuncture ond0,21,and42. AVacutainertube(BD,FranklinLakes,NJ) containingsodiumheparinanticoagulantwasusedtocollect10mLofwholebloodfro meach lamb,andthetubeswerestoredonice.Thebloodwascentrifugedat 1920 g for20minat4 o C toseparatetheplasma,whichwasstoredat 20 o Cuntilanalyzed. Ruminalfluidwascollected from24lambs( 4 pertreatment)onthelast d ofeachper iodbyaspirationwithorally inserted stomachtubes0,2,4,6,8and10hafterthemorningfeeding.Arepresentative(100mL) sampleofruminalfluidwasanalyzedimmediatelyforpH (Accumet,modelHP 71,Fischer

PAGE 91

91 Scientific,Pittsburg,PA)and acidifie dwithconcentratedH 2 SO 4 ,centrifugedfor30minat4 o C and2795 g andfrozen( 20 o C)forsubsequentanalysis. ChemicalAnalyses Samplesoffeed,ortsandfecesweredriedat60 o C for48htodetermineDMconcentration anddriedsamplesweregroundtop assthrougha1 mmscreeninaWileymill(ArthurH. ThomasCompany,Philadelphia,PA).Sampleswereanalyzedforashbycombustioninamuffle furnaceat600 o Covernight.TotalNconcentrationwasdeterminedbyrapidcombustionusinga macroelementalN analyzer(Elementar,varioMAXCN,ElementarAmericas,MountLaurel, NJ)andusedtocalculateCP(CP=N 6.25).Neutraldetergentfiberconcentrationwas measuredusingthemethodofVanSoestetal.(1991)inanANKOM200FiberAnalyzer (ANKOMTechn ologies,Macedon,NY).AmylasewasusedforNDFanalysisandtheresults wereexpressedonaDMbasis.FeedsampleswereanalyzedforADFwiththemethodofVan Soestetal.(1991)inanANKOM200FiberAnalyzer(ANKOMTechnologies,Macedon,NY). Anada ptation (ANKOM,2005b) ofthemethodofAOAC(1990)thatinvolvedweighing samplesintoANKOMF57filterbagswasusedforADLdetermination. TheANKOM(2005a) adaptationoftheVanSoest etal. (1966)methodforanANKOMDaisy II Incubator (ANKOM Technolo gy,Macedon,NY) andtheANKOM200FiberAnalyzerwasusedtodetermineinvitro truedigestibility(IVTD).ApparentdigestibilityofDM,OM,NDFandNwerecalculated. UrinewasanalyzedforNusingamodifiedaluminumblockdigestionmethod(Gallahere t al.,1975)andNconcentrationwasquantifiedwithanALPKEMautoanalyzer(ALPKEM Corporation,Clackamas,OR).Totalpurinederivatives(PD)intheurinewereanalyzedas allantoin(Bochers,1977).Xanthine,hypoxanthineanduricacidwereconvertedt oallantoin usingtheenzymeprocedureofFujiharaetal.(1987).MicrobialNsupplytothesmallintestine wascalculatedfromtheurinaryoutputofPDusingtheequationofChenetal.(1992).

PAGE 92

92 Volatilefattyacidsinruminalfluidweremeasuredusingt hemethodofCanaleetal. (1984) using aHighPerformanceLiquidChromatograph(Hitachi,FL7485,Tokyo,Japan) coupledtoaUVDetector(Spectroflow757,ABIAnalyticalKratosDivision,Ramsey,NJ)setat 210nm.ThecolumnusedwasaBio RadAminexHPX 87H(Bio Radlaboratories,Hercules, CA)with0.015MH 2 SO 4 mobilephaseandaflowrateof0.7mLat45 o C .Theconcentrationof NH 3 NconcentrationinruminalfluidwasdeterminedusingtheALPKEMautoanalyzerandan adaptationoftheNoelandHambleton (1976)procedu rethatinvolvedcolorimetricquantification ofN.Plasmaglucose(PGlu)andureaN(PUN)concentrationsweremeasuredusingadaptations foraTechniconAutoanalyzerII(Bran Luebbe,Elinsford,NY)andmethodsofGochmanand Schmidz(1972) andCoulombeandFavreau(1963)respectively. StatisticalAnalyses DatawereanalyzedwithPROCMIXED(SASInst.Inc.,Cary,NC).Themodelfor analyzingchemicalcompositionoffeedsincludedforagespeciesandperiod(randomvariable). Themodelfora nalyzingintake,digestibility,Nexcretionandretention,MPparameters,PUN andPGluincludeddietarytreatment,period,dietarytreatmentperiod,andlamb(random variable) .Dietarytreatment,timeofcollection(repeatedmeasure),period,theintera ctions,and lamb(randomvariable)wereincludedinthemodelforanalyzingruminalfluidpH,NH 3 Nand VFA.MeanswereseparatedwithaPDIFFstatement.Significancewasdeclaredwhen P <0.05 andtendencieswhen P >0.05and 0.10. Results ForageChemicalComposition TheDMandOMconcentrationsofallhaylagesweresimilar( P >0.10)(Figure6 1). Bahiagrasshaylagetended( P 0.07)tocontainlessCPthanthelegumehaylages.Amongthe legumes,theCPconcent rationofannualpeanuthaylagewasgreaterthanthatofpigeonpea

PAGE 93

93 haylage.ConcentrationofNDFwasgreatest( P <0.10)inpigeonpeaandbahiagrasshaylages, butpigeonpeahadgreater( P <0.10)ADFconcentrationthantheotherhaylages.TheADL concent rationsofcowpeaandpigeonpeahaylagetended( P 0.08)tobegreaterthanthatof bahiagrass.TheIVTDwasgreaterinannualandperennialpeanuthaylagesthanbahiagrassand pigeonpeahaylages,andthelowest( P <0.01)IVTDwasinpigeonpeahaylage. Item Bahia Annual p eanut Perennial p eanut Cowpe a Pigeonpea SEM 1 DM,% 52.1 54.3 49.2 53.0 47.6 1.32 OM,%DM 96.9 95.7 95.9 93.9 95.8 0.79 CP,%DM 9.6 c 18.7 a 15.8 ab 16.0 ab 13.7 bc 1.23 NDF,%DM 67.8 a 39.6 b 40.0 b 44.1 b 65.0 a 2.40 ADF,%DM 32.2 b 25.3 bc 24.1 c 29.8 bc 48.6 a 1.99 Lignin,%DM 6.2 11. 7 7.1 14.4 14.0 2.54 IVTD,% 60.4 b 73.8 a 76.9 a 68.6 ab 38.3 c 3.11 IntakeandDigestibility A llsupplements,exceptpigeonpea,increasedDMandOMintakes(Table6 2).Intakeof DMwasgreaterinlambsfedperennialpeanuthaylageandintakesofOM weregreaterinlambs fedperennialpeanutorsoybeanmealthaninthosefedcowpeaorpigeonpeahaylages.Lambs fedbahiagrassaloneorsoybeanmealhadgreaterNDFintakesthanlambssupplementedwith annualpeanutorpigeonpeahaylages. Apparentdige stibilityofDMwasgreater( P <0.01)insheepfedsoybeanmealthanin sheepfedbahiagrasshaylagealoneorpigeonpea.DigestibilitiesofDMandOMweresimilarin Table6 1. Chemicalcompositionandinvitrotruedigestibility(IVTD)of haylages 1 SEMvaluesreflectthevariationofsamplescollecteddailyandcomposited withinperiod(n=2). Withinarowmeanswithoutacommonsuperscriptletterdiffer( P <0.05).

PAGE 94

94 lambsfed bahiagrasshaylagealoneandthosefedlegumesupplements,exceptpigeonpea wh ich hadlowervalues. DigestibilityofNDFwasgreatestinlambsfedbahiagrasshaylage,andlowerinlambs fedannualpeanuthaylagethaninlambssupplementedwithsoybeanmealorcowpeahaylage. DigestibilityofNDFwasreducedwhenbahi agrasswassupplemented,andthereductionwas greater( P <0.01)whenannualpeanutwassupplementedinsteadofsoybeanmeal. NitrogenUtilizationandBloodMetabolites Nitrogenintakewasgreatest( P <0.01)inlambsfedsoybeanmeal,followedbyannual peanuthaylage,andlowest( P >0.10)inlambsfedbahiagrasshaylagealoneorpigeonpea haylage(Table6 3).Feca lNoutputwasgreatestinlambsfedannualpeanuthaylageandlowest ( P <0.01)whenbahiagrassorpigeonpeahaylageswerefed.UrinaryNexcretionwassimilar amongdietarytreatments.RetainedNwasgreatestinlambsfedsoybeanmeal,followedby ann ualorperennialpeanutandcowpeahaylages,andlowest( P <0.01)inlambsfedbahiagrass haylagealoneorpigeonpeahaylage.DigestibilityofNwasgreatest( P <0.01)inlambs Item Bahia SBM Annual p eanut Perennial p eanut Cowpea Pigeonpea SEM Total i ntake,g/d DM 644 c 791 ab 771 ab 809 a 74 7 b 491 d 20.3 OM 624 c 766 a 742 ab 780 a 713 b 473 d 19.5 NDF 457 ab 488 a 419 c 447 bc 437 bc 340 d 11.7 Digestibility,% DM 65.2 b 68.0 a 65.5 ab 66.7 ab 67.0 ab 58.7 c 0.9 OM 65.1 a 66.2 a 65.2 a 66.2 a 66.4 a 58.9 b 1.1 NDF 70.1 a 66.6 b 61.8 c 64.2 bc 65.6 b 6 4.1 bc 1.2 Withinarowmeanswithoutacommonsuperscr iptletterdiffer( P <0.05). Table6 2.Intakeand apparentdigestibilit y( DMbasis)ofb ahiagrass haylage supplemented with orwithout legumehay lage sorsoybeanmeal(SBM)

PAGE 95

9 5 Measurement Bahia SBM Annual p eanut Perennial p eanut Cowpea Pigeonpea SEM Nitrogenintake,g/d 10.5 d 20.6 a 18.4 b 16.8 c 16.4 c 10.1 d 0.52 FecalNoutput,g/d 4.2 c 5.3 b 6.0 a 5.3 ab 5.1 b 3.7 c 0.31 UrinaryNoutput,g/d 4.1 6.1 5.4 5.5 5.1 3.5 0.73 RetainedN,g/d 2.1 c 9.2 a 6.9 b 5.9 b 6.2 b 2.8 c 0.86 Ndigestibility,%DMb asis 58.5 c 73.9 a 68.0 b 67.6 b 67.6 b 61.1 c 1.24 PD 1 output,mmol/d 11.3 ab 13.5 a 11.4 ab 11.4 ab 10.3 b 7.5 c 0.89 MicrobialN,gN/d 10.1 ab 11.7 a 9.9 ab 10.4 ab 9.0 b 6.5 c 0.87 DOM,g/d 405 c 510 a 482 ab 518 a 474 b 268 d 12.73 Microbialefficiency, gmicrobialN/kg DOM 24.9 23.5 20.8 20.4 19.2 24.5 2.09 PUN 2 ,mg/dL 9.7 c 16.5 a 12.5 b 11.9 bc 10.1 bc 10.4 bc 0.86 PGlu 3 ,mg/dL 62.9 67.2 65.4 67.3 64.0 62.9 1.71 Table6 3. Nitrogenbalance,microbialNsynthesis,apparentlydigestedOM(DOM),a nd bloodmetabolitesoflambsfe dbahiagrass haylage supplementedwithwarm season legume haylages orsoybeanmeal(SBM) 1 Urinarypurinederivatives 2 Plasmaureanitrogen 3 Plasmaglucose Withinarowmeanswithoutacommonsuperscriptletterdiffer( P <0.05).

PAGE 96

9 6 Measurement Bahia SBM Annual p eanut Perennial p eanut Cowpea Pigeonpea SEM RuminalpH 6.8 ab 6.7 bc 6.8 a 6.8 ab 6.8 ab 6.7 c 0.1 AmmoniaN,mg/ d L 4.2 d 12.0 a 10.3 b 9.5 b 7.2 c 7.8 c 0.5 TotalVFA,mmol/L 107.7 b 106.8 b 125.0 a 131.9 a 112.9 b 108.5 b 4.2 Acetate, mol/100mol 59.8 a 58.6 a 58.0 abc 56.1 c 57.0 bc 59.5 a 0.7 Propionate, mol/100mol 20.4 20.4 20.4 19.7 19.5 19.7 0.5 Iso butyrate, mol/100mol 3.9 4.3 4.4 3.9 4.8 4.3 0.3 Butyrate, mol/100mol 10.0 b 10.3 b 10.9 b 12.8 a 10.9 b 10.2 b 0.3 Iso valerate, mol/1 00mol 4.6 4.5 4.2 5.6 4.9 4.4 0.5 Valerate, mol/100mol 2.1 2.5 3.0 2.2 2.8 2.5 0.4 Acetate: p ropionate 3.0 2.9 2.9 2.9 3.0 3.1 0.1 Table6 4. RuminalfluidpH,NH 3 NandVFAconcentration soflambsfedbahiagrasshaylage supplementedwithwarm seasonlegumehaylagesorsoybeanmeal(SBM) Withinarowmeanswithoutacommonsuperscriptletterdiffer( P <0.05).

PAGE 97

97 supplementedwithsoybeanmeal,followedbyannualandperennialpeanutandco wpea haylages,andlowest( P <0.01)inlambsfedbahiagrasshaylagealoneorpigeonpeahaylage. PurinederivativeexcretionandmicrobialNproductionweresimilarinlambsfedbahiagrass haylagealone,soybeanmeal,andannualorperennialpeanuthaylag es,andthelowestvalues occurredinlambsfedpigeonpeahaylage.DigestibleOMintakewaslowerinlambsfedan bahiagrasshaylagealoneorpigeonpeahaylagethaninothers.Theefficiencyofruminal microbialNproductionandPGluconcentrationswere similaramongdiets,butsupplementation withsoybeanmealorannualpeanuthaylageincreasedPUNconcentration. RuminalFluidpH,NH 3 NandVFA RuminalfluidpHwasslightlylowerinlambsfedsoybeanmealorpigeonpeahaylage supplementthanlambsfed annualpeanuthaylage.RuminalNH 3 Nconcentrationwasgreatest inlambsfedsoybeanmeal,followedbyannualandperennialpeanuthaylages,andlowestwhen bahiagrasshaylagewasfedalone.ProportionsofmostindividualVFAwerenotdifferentamong die tarytreatments.TotalVFAconcentrationwasgreatestinruminalfluidoflambsfedannualor perennialpeanuthaylages.Molarproportionofacetatewasgreaterintheruminalfluidoflambs fedbahiagrasshaylagealone,soybeanmeal,orpigeonpeahaylag ethanthosefedperennial peanutorcowpeahaylages.Theproportionofbutyratewasgreaterintheruminalfluidoflambs fedperennialpeanutthantheotherdietswhichhadsimilarproportionsofbutyrate. Discussion TheCPconcentrationsofannualand perennialpeanuthaylagesweresimilartothose reportedbyJohnsonetal.(1979)andStaplesetal.(1997)respectively,butNDFandADF concentrationswerelowerbecausethisstudyinvolvedlessmatureforages.Norecent(>1900) publishedinformationo nthenutritivevalueofbahiagrass,pigeonpeaorcowpea haylage was

PAGE 98

98 found,buttheCP,NDFandADFconcentrationsofthebahiagrasshaylageinthisstudyare similartothoseofbermudagrasssilage(Deanetal.,2005). TherankingofhaylagesbyIVTDwas similartotherankingbyapparentinvivoDM digestibilityindicatingthattheIVTDmethodfordeterminingnutritivevalueisvalidforthe se warm seasonlegumes.DifferencesinIVTDforthesehaylagescanbepartlyexplainedby differencesintheirNDF, ADFandADLconcentrations.Apartfrompigeonpea,legume haylage shadgreaterIVTDthanbahiagrasshaylagebecausetheycontainedlessNDF.Although theNDFconcentrationofpigeonpeawassimilartothatofbahiagrass,pigeonpeahadalower IVTDbecause itcontainedmoreADF. Whenbasalgrassdietsofsheeparesupplementedwithlegumes,DMintakeincreases becauseofthefasterrateofpassageoflegumes,whichistheprimaryfactoraffectingintakein ruminants(Bowmanetal.,1991).Legumeshave lessstructuraltissueandmoreeasily degradablemesophylltissuethanwarm seasongrassesbecauseofanatomicaldifferences associatedwiththeirphotosyntheticpathways(AkinandBurdick,1975;Wilson,1994).The absenceofKranzandgirderstructures inlegumesandthereticulatevenationoflegumeleaves relativetotheparallelvenationofgrassleavesresultsinlowerNDFconcentrationsandgreater ratesofparticlepassageinlegumes(Frame,2005).LowerdietaryNDFconcentrationsare correlatedw ithgreaterparticlesizereductionthroughmasticationandfermentation(Meissner andPaulsmeier,1995;Ellisetal.,2005).Supplementationwithpigeonpea haylage decreased DM,OM,andNDFintakesbecauseitsthick,woodystemswouldhavecausedgreater gutfill t hanstemsofbahiagrass.Incontrast,additionofsoybeanmealincreasedDMintakesbecause theincreasedproteinsupplytoruminalmicrobesincreasedDMdigestibility.

PAGE 99

99 Supplementationwithlegume haylage sdidnotincreaseDMdigestibility.S imilarly, supplementationofaryegrass silage ( Lolium perenne L. cv. Augusta )basaldietwitheither red clover( Trifoliumpratense L. cv. Milvus),whiteclover( Trifoliumrepens L. cv. Aran),oralfalfa ( Medicagosativa L. cv. Vertus) silages increasedDM intakebutnotDMdigestibility(Dewhurst etal.,2003b).Thiswasattributedtotheinverserelationshipbetweenrateofpassageand digestibility(Dewhurstetal.,2003a)becausetherapidrateofpassageoflegumesoftenlimits theircolonizationand degradationbyruminalmicrobes.Furthermore,thegreaterlignin concentrationoflegumesalsolimitstheird igestibilityrelativetothatofgrasses(Wilson,1994). LambsfedsupplementeddietshadgreaterruminalNH 3 Nconcentrationsbecausemostof th eproteininlegumesandsoybeanmealishighlyru mendegradable(Broderick,1995 ).For maximummicrobialNproductionintherumen,anNH 3 Nconcentrationof5 0mg/ d Lis recommendedthoughthelimitingconcentrationisapproximately2 0mg/ d L(Satteran dSlyter, 1974).Therefore,supplementationwasnecessarytoachieverecommendedlevelsfor maximizingmicrobialgrowth.DigestibleOMintakeispositivelycorrelatedwithmicrobial synthesis(Clarketal.,1992),andallsupplementsexceptpigeonpeahay lageincreaseddigestible OMintake.Therefore,itissurprisingthatmicrobialNsynthesiswasnotincreasedbysuch supplements.Microbialefficiencyisconsideredlowwhenitfallsbelow20gmicrobialN/kg digestibleOMintake,andhighwhenitisgr eaterthan35gmicrobialN/kgdigestibleOMintake (Dewhurstetal.,2000).Therefore,theefficiencyofmicrobialNsynthesisfromthedietswas lowtomoderate. ThetotalVFAconcentrationsinruminalfluidwerenormalbutlambsfedannualand perenn ialpeanuthaylage diet shadconcentrationsthatexceededthenormalrange(100to120 mmol/L)inforagefedruminants(Bergman,1990),reflectingthehighfermentabilityofthese

PAGE 100

100 legumehaylages.MolarproportionsofVFAweresimilartonormalvaluesin foragefedanimals (Bergman,1990)anddifferencesinmolarproportionsofacetateamongdietspartlyreflected theirNDFconcentrations. Kenako(1989)reportedtherespectivenormalphysiologicalrangesofPUNandPGluin sheepis8to20mg/dLand50t o80mg/dL,respectively,andvaluesforlambsinthisstudywere withintheseranges.PlasmaureaNconcentrationsweregreaterinlambsfedsoybeanmealand annualpeanutthanthosefedbahiagrass alone becausetheformerdietsresultedinthegreatest increaseinruminalNH 3 Nconcentrations. TheNstatusofsupplementedlambswasbetterthanthatoflambsfedonlybahiagrass haylage.P erennialpeanutandannualpeanuthaylagewerethebestlegumesupplementsbecause theyincreasedDM,OM,andNinta kes,Ndigestibility,ruminalNH 3 N,PUN,andNretention relativetofeedingbahiagrasshaylagealone.Inadditiontotheseeffects,soybeanmeal supplementationresultedinthegreatestNintake,digestibility,andretentionandthegreatestDM digestib ility,indicatingthatitwasthebestsupplement.Supplementationwithpigeonpeawas notbeneficialbecauseitresultedinlowerintakesanddigestibilityofDMandOMandlower microbialNproduction.Furtherstudiesshouldanalyzetheproteindegrada bilityofthelegume haylages.

PAGE 101

101 CHAPTER7 EFFECTSOFCREEP FEEDINGORCREEP GRAZINGWARM SEASONLEGUMESON THEPERFORMANCEOFB EEFCATTLE Introduction Bahiagrass( Paspalumnotatum Flgge)isapersistentwarm seasongrassthatisgrownfor grazingandforhayproductioninthesoutheaste rnUnitedStates.Bahiagrasstoleratestreading andcontinuous,closedefoliationbylivestock andismoreproductivethancomparablewarm seasongrasseswhengrownonsandy,acidicsoils(RedfearnandNelson,2003).Bahiagrass providesadequatenutriti onformaintenanceofbeefcowsfromlatespringtoearlyautumn. However,theCPconcentrationandenergyprovidedbybahiagrassisinadequateforgrowingand lactatingcattle,especiallylateinthegrazingseasonwhentheforagematures(Mooreetal., 1991;Johnsonetal.,2001).Legumeshaveasymbioticrelationshipwithsoilbacteriathatfix atmosphericN;thereforelegumeshavegreaterCPconcentrationthangrasses.Legumesmaybe utilizedtoprovidesupplementaryruminallydegradableproteinand fermentableenergyto growingcattleonbahiagrasspastures.Inter seedinglegumesintowarm seasonpasturesis problematicduetocompetitionbetweengrassandlegumespeciesandpreferentialselectionof legumesbycattle (Harrelsonetal.,1994; Leep etal.,2002 ; RedfearnandNelson,2003 ) .Creep grazingisanalternativemethodofutilizinglegumesingrass basedpasturesystems,which allowspre weanedanimalstoconsumehighqualityforages. Creepgrazing aeschynomene ( Aeschynomeneamericana L.), orhairyindigo( Indigoferahirsuta L.)orperennialpeanut ( Arachisglabrata Be nth )hasincreasedtheADGofsucklingcalvesby0.1to0.2kg/d (OcumpaughandDusi,1981;Williamsetal.,2004;Corriheretal.,2007).Theeffectsofcreep feedingconc entrates(Tarretal.,1994;Loyetal.,2002)andfibrousbyproducts(Soto Navarroet al.,2004)tocalvesoncowandcalfperformancehavebeenstudiedextensively,butlimited informationisavailableontheeffectsof creepgrazing warm season legumes. Perenni alpeanut

PAGE 102

102 isgrownonabout10,0 00hainFlorida(Flores,2008),andwhenfedassupplementalhaytoa basalbahiagrasshaydiet,DMintakeandNretentionwereincreasedinlambs(Chapter4). Cowpea( Vignaunguiculata (L.)Walp. )isatropically adapted,warm seasonseededlegumeand theseedsarewidelyavailable.In N orthFlorida,aherbagemassofupto5,000kgDM/haand aninvitrotruedigestibility(IVTD)of80%werereportedforcowpea(Chapter3).However,no publishedstudiesoneffe ctsof creepgrazing calvesoncowpeawerefound andlittlepublished informationexistsoneffectsofcreepgrazingperennialpeanut .Theaimoftheseexperiments wastodeterminetheeffectsofcreepgrazingwithperennialpeanut( cv. Florigraze )orcow pea ( cv. Ironclay ),orcreepfeedingaconcentrateonintakeanddailygainsinbeefcattlegrazing bahiagrass( cv. Tifton9or cv. Argentine)pasturesinFlorida. MaterialsandMethods AnimalsandForages AllanimalprocedureswereapprovedbytheUniv ersityofFloridaInstitutionalAnimal CareandUseCommittee.ThisexperimentwasconductedattheNorthFloridaResearchand EducationCenterinMarianna,FL (31N) .Cowsandtheirpre weanedcalveswere continuouslystockedoneitherTifton9(Experi ment1)orArgentine(Experiment2)bahiagrass pasturesandcalveshadcontinuousaccesstonocreepareaortolegumeorconcentratecreep areas(0.12ha).Creepareaswereseparatedwithelectricalfencingandwoodencreepgates(2.4 1.2mwith4,40 cmwideopenings).Mineralsandwaterwereprovided adlibitum closetoa shadedareawithinthepaddockthatwassituatednearthecreepgatetoencouragethecalvesto enterthecreeparea.Themineralandvitaminpremix(PurinaWind&RainAllSeason 12,St. Louis,MO)containedonaverage13%Ca,12%P,3%NaCl,1%Mg,1%K,7.4%Zn,4.2%Mn, 2.2%Cu,0.1%Co,0.2%I,54ppmSe,110,000IU/kgVitaminA,33,000IU/kgVitaminD,and 330IU/kgVitaminE.

PAGE 103

103 Experiment1 TwelveBranguscow calfpairswere stratifiedbyweightandageandassignedrandomlyto sixtreatmentpaddocks(1.2haeach)containingestablishedstandsofTifton9bahiagrasswithno creeparea(control)orwithcowpeaorperennialpeanut creepgrazing areas(0.12haeach). Cowsweighe d55998kgandcalvesweighed15232kgatthebeginningoftheexperiment. Paddockswereassignedrandomlyto 2 blocksthatdifferedinsoiltypesuchthateachblock contained3paddocks.SoilontheexperimentalsitewaspredominatelyChipolaloa mysand (loamy,kaolinitic,thermic,ArenicKanhapludults)andOrangeburgloamysand(fine loamy, kaolinitic,thermic,TypicKandiudults).Perennialpeanutwassprig plantedintocreepgrazing areas2 yrpriortocommencingtheexperiment.Thecowpea cre epgrazing areawaspreparedby applying2.8L/haofPendimax(Pendamethalin,DowAgroSciences,Indianapolis,IN)and0.11 L/haofPursuit(Imazethapyr,BASFChemicalCompany,FlorhamPark,NJ)anddisking. Fertilizerwasappliedandplowedintothesoil atarateof 310 kg/ha(7 18 29ratioof N:P 2 O 5 :K 2 O).Cowpeaseedswereinoculatedwith Bradyrhizobium spp.(BeckerUnderwood, Inc.,RoyalPeat,Ames,IA)anddrilledat56kg/haand 15 cm rowspacingonMay18,2007.To preparebahiagrasspasturesforg razing,115kg/haoff ertilizer(34 22 22ratioof N:P 2 O 5 :K 2 O) wasapplied andtheyweremowedtoa 20 cmstubbleheight .Twocow calfpairsgrazedeach paddockfromJune29,2007,untilthecowpeawascompletelyconsumed12wklater. During wk6,7,10, and12,digitalvideocameraswereusedtorecordentryofcalvesintocreepareas from0600to0900.Therewasnorecordingintheeveningduetorainfallandearlyonsetof darkness. Experiment2 TwelveBranguscow calfpairswerestratifiedbyweight andageandassignedrandomlyto sixtreatmentpaddocks(1.3haeach)containingestablishedstandsofArgentinebahiagrasswith

PAGE 104

104 nocreeparea(control)oracreeparea(0.21ha)containingeithercowpeaoraconcentratecreep feed.Cowsweighed55998 kgandcalvesweighed15232kgatthebeginningofthe experiment.Paddockswereassignedrandomlyto 2 blocksthatdifferedinsoiltypesuchthat eachblockcontained3paddocks.SoilontheexperimentalsitewaspredominatelyGreenville finesandy loam(clayey,kaolinitic,thermicRhodicKandiudults)andOrangeburgloamysand (fine loamy,kaolinitic,thermic,TypicKandiudults)andblockswerearrangedaccordingly. CowpeawasestablishedasinExperiment1.Topreparebahiagrasspasturesforgrazi ng196 kg/haf ertilizer(20 0 10ratioof N:P 2 O 5 :K 2 O) wasapplied topasturesinthespringandthey weremowedtoa 20 cm stubbleheight. Theconcentrate waspelletedanditcontainedamixture ofcornandcottonseedmeal.Thechemicalcompositionwas: 91.01.0%DM,97.50.2% OM,11.20.1%CP,16.91.3%NDF and87.81.0%IVTD (DMbasis) Twocow calf pairsgrazedeachpaddockasinExperiment1andentryofcalvesintocreepareaswasalso recorded. Bothexperimentsoccurredconcurrently, andcalveswereweanedattheendofthe trial. SampleCollection MonthlyrainfallandtemperaturedatawererecordedviatheFloridaAutomatedWeather Networklocatedonsite(FAWN,2008).Rainfallandtemperatureaveragesover30 yr for Marianna,FL,we reobtainedfromtheFloridaClimateCenter(FCC,2008).Tocalibratethe doublesamplingequationforpredictingbahiagrassherbagemassfromdiskheight(Bransbyet al.,1977),herbagewithin 0.2 m 2 quadratswasharvestedtoa5 cmstubbleheightfroma bout20 locationsineachpaddockatwhichdiskheightwasalsomeasured atwk0,4,8,and12 Atwk 2,6,and10diskheightmeasurementsweretakenandthedoublesamplingequationutilizedto estimateherbagemassofbahiagrass. Herbagemassoflegum esincreepareaswasmeasuredby harvesting 3 representativesampleswithin 0.2 m 2 quadratstoa5 cmstubbleheightat 2 wk

PAGE 105

105 intervals.Representativehand pluckedsamplesofeachforageweretakenfornutritivevalue analysisbysamplingatseveralpoin tsalongaWtransectinpaddocksorcreepareasevery2wk. Bahiagrasssamplesincludedthetop5cmandperennialpeanutandcowpeasamplesincludedthe top3cmand6cm,respectively.Thecreepconcentratewassampledfrombothfeedersatthe starto fthetrialandevery2wkthereafter.Todetermineleaf to stemratioandweed contaminationwithincreep grazingareas,severaladditionalrepresentativesampleswere harvestedtoa5 cmstubbleheightfrom 0.2 m 2 quadratsatwk4,8and12.Leaveswe re separatedfrom thestematthenodewithin2h ofsampling. CowandcalfBWweremeasuredatthestartoftheexperimentsandevery4wkfollowing at0800.Calf205 dBeefImprovementFederation(BIF)adjustedweaningweightswere calculated(BeefI mprovementFederation,2006).Ateachweighing,BCS(1 9scale)was determinedbythesameexperiencedobserverandblood samplesweretakenfromeachcowand calfviajugularpuncture.AVacutainertube(BD,FranklinLakes,NJ)containingsodium heparin wasusedtocollect10mLofwholebloodandthetubeswerestoredonice. Theblood wascentrifugedat1920 g for20minat4 o Ctoseparatetheplasma,whichwasstoredat 20 o C untilanalyzed. ChemicalAnalyses Allforagesampleswereweighedandd riedat 65 o C for48 h inaforcedairoven to determineherbageDMyield.Driedsampleswere groundtopassthrougha1 mmscreenina Wileymill(Arthu rH.ThomasCompany,Philadelphia,PA)andanalyzedforresidualDMby ovendryingat105 o Covernight, andforashbycombustioninamufflefurnaceat600 o C overnight.TotalNwasdeterminedbyrapidcombustionusingamacroelementalNanalyzer (Elementar,varioMAXCN,ElementarAmericas,MountLaurel,NJ)andusedtocomputeCP (CP=N 6.25).Neutr aldetergentfiberconcentrationwasmeasuredusingthemethodofVan

PAGE 106

106 Soestetal.(1991)inanANKOM200FiberAnalyzer(ANKOMTechnologies,Macedon,NY). AmylasewasusedforNDFanalysisandtheresultswereexpressedonaDMbasis.An adaptation (ANK OM,2005a) oftheVanSoest etal. (1966)methodforanANKOMDaisy II Incubator (ANKOM Technology,Macedon,NY) andanANKOM200FiberAnalyzerwasused todetermineIVTD.Plasmaglucose(PGlu)andureaN(PUN)concentrationsweremeasured usingadaptatio nsforaTechniconAutoanalyzerII(Bran Luebbe,Elinsford,NY)andmethodsof GochmanandSchmidz(1972)andCoulombeandFavreau(1963),respectively. StatisticalAnalyses Bothexperimentshadrandomizedcompleteblockdesignswith 2 blocksand 1 replic ateof eachtreatmentwithineachblock.TheMIXEDprocedureofSAS(SASInst.Inc.,Cary,NC) wasusedfordataanalyses.Themodelusedtoanalyzeherbagemass,legumeleaf to stemratio andchemicalcompositionofforagesamplesincludedforagespecie s,wk,block(random variable),andtheinteractions.Themodelusedtoanalyzecowandcalfbloodmetabolitesand cowBCSincludedwk,treatment,block(randomvariable),andtheinteractions.Therespective initialmeasurementswereusedascovariates. Polynomialcontrastsforlinearandquadratic effectswereusedtoanalyzetrendsovertime.Themodelusedtoanalyzetheotheranimal productionresponsesincludedtreatmentandblock(randomvariable).Covariateadjustmentsfor calfbirthweight,ca lfageandcowagewereusedforcalfinitialBW.Covariateadjustmentsfor calfbirthweight,calfage,calfinitialbodyweightandcowagewereusedforcalffinalBWand cowandcalfADG.SignificanttreatmenteffectswereseparatedwithaPDIFFstat ement. Significancewasdeclaredat P <0.05andtendenciesat P >0.05and 0.10. Results Monthlyaverage s ofthedailyhighandlowaveragetemperatures duringtheexperiment werenotdifferentfrom30 yraveragesexceptthatMaywaswarmer(Figure7 1).Theamount

PAGE 107

107 ofrainfallduringtheexperimentvariedbetweenmoandwassufficientlybelowthe30 yr averagestohavelimitedforagegrowth(Figure7 2;WilliamsandHammond,1999). Experiment1 Pasture HerbageMass andNutritiveValue Themeanherbagemassofthe 3 foragespeciesweresimilar( P =0.11;1 92 0 152,1 5 70 142,and2 20 0 83kgDM/haforcowpea,perennialpeanut,andbahiagrass,respectively), thoughthatofcowpeawasgreater( P <0.01)thantheo thersatwk2and4(Figure7 3). HerbagemassofTifton9bahiagrasspastureincreasedquadraticallyfromapproximately1,100 Figure7 1. Monthlyaveragetemperature ( C ) in2007and30 yraverageinMarianna,FL Figur e7 2.Monthlyaveragerainfall(cm) in2007and30 yraverageinMarianna,FL

PAGE 108

108 kgDM/haintheearlysummertoapeakof2,700kgDM/haatwk8.Herbagemassofperennial peanutdecreasedlinearlyfrom2,00 0to650kgDM/hathroughthegrazingperiod,whereasthat ofcowpeaincreased( P <0.06)toapeakof3,700kgDM/haatwk4andthendeclinedto300kg DM/haatwk12.Therewasslight(14%DMbasis)weedcontaminationofcowpeacreepareas at8wkbut bywk12,allthecowpeaandweedshadbeenconsumed.Perennialpeanutcreep areascontainedabout22%(DMbasis)weedcontaminationthroughoutthegrazingtrial. Theleaf to stemratioofcowpearemainedunchangedthrou ghoutthegrazingperiod, whereasthatofperennialpeanutdecreasedlinearly(Figure7 4).Atwk4,theleaf to stemratio ofperennialpeanutwasgreaterthanthatofcowpea,butatwk12thatofcowpeawasgreater. TheNDFconcentrationofbahiagrassi ncreasedquadratically,butthatofcowpeadeclined linearly,whereasthatofperennialpeanutdidnotchangethroughthegrazingperiod(Figure7 5). TheNDFconcentrationsofcowpeaandperennialpeanutwerelessthanthatofbahiagrass Figure7 3.Changesinherbag emassofTifton9bahiagrasspasturesandcowpeaand perennialpeanutcreepareasduringthegrazingperiod SEM= 3 7 5;Species( P >0. 11);Weekspecies( P <0.001) 1 Linear(L);quadratic(Q)polynomialcontrastsforweekofgrazingeffects,***( P < 0.001); *( P >0.05) ;( P <0.10) Meansateach week withoutacommonsuperscriptletterdiffer( P <0.05).

PAGE 109

109 throughoutthegrazingperiod,andtheyweregenerallysimilarexceptatwk8and12when cowpeahadlowerconcentrations.TheCPconcentrationofbahiagrassandcowpeadecreased linearlyduringtheexperiment,butthatofperennialpea nutincreasedlinearlyfrom13to17%of DM.Throughouttheexperiment,cowpeacontainedmore( P <0.01)CPthanperennialpeanut, andperennialpeanutcontainedmoreCPthanbahiagrassfromwk2to12.TheIVTDof bahiagrasspasturesdeclinedlinearlyt hroughthegrazingperiodbutthoseofcowpeaand perennialpeanutfluctuated.TheIVTDofcowpeaandperennialpeanutweresimilarandthey weregreaterthanthatofbahiagrass. AnimalPerformance CalfBWwassimilaramongtreatments(Figure7 6). Cre epgrazing perennialpeanut increasedcalf205 dBIF adjustedweaningweightwhereas creepgrazing cowpeatended( P = 0.09)toincreasecalfADG(Table7 1).Cowsinthecowpeatreatmenthadgreater( P < 0.01) SEM=0.15;Species( P <0.005 );Weekspecies( P < 0.001 ) 1 Linear(L)polynomialc ontrastforweekofgrazingeffects,***( P <0.001) Meansateach week withoutacommonsuperscriptletterdiffer( P <0.05). Figure7 4.Changesinleaf to stemratioofcowpeaandperennialpeanutduringthe grazingperiod

PAGE 110

110 Figure7 5.ChangesinNDFan dCPconcentrations(DMbasis)andinvitrotruedigestibility (IVTD)ofTifton9bahiagrasspastureandcowpeaandperennialpeanutcreepareas duringthegrazingperiod a)NDF,%;SEM=1.6;Week( P <0.001);Species( P <0.001);Weekspecies( P <0.001) b)CP,%;SEM=1.6;Week( P <0.004);Species( P <0.001);Weekspecies( P <0.001) c)IVTD,%;SEM=7.9;Week( P >0.63);Species( P <0.02 );Weekspecies( P >0.83) 1 Linear(L);quadratic(Q)polynomialcontrastsforweekofgrazingeffects,***( P <0.001); *( P <0.01);* ( P < 0.05) Meansateach week withoutacommonsuperscriptletterdiffer( P <0.05).

PAGE 111

111 Item No c reep Pe anut c reep Cowpea c reep SEM 1 P value Calf a ge,d 105 122 118 8.5 0.36 Initial c alfBW,kg 155 152 147 4.5 0.51 Weaned c alfBW,kg 247 247 264 7.5 0.1 7 205 dBIF 2 adj.wt.,kg 267 b 319 a 278 ab 19.4 0.05 Calf83 dADG,kg 1.15 1.15 1.36 0.08 0.09 Cow83 dADG,kg 0.27 0.20 0.39 0.10 0.47 CowBCS 5.4 b 5.4 b 5.8 a 0.11 <0.01 CalfPUN 3 ,mg/dL 7.4 b 9.8 ab 11.1 a 0.96 0.05 CowPUN,mg/dL 5.8 7.0 7.5 1.24 0. 35 CalfPGlu 4 ,mg/dL 72.4 b 75.3 b 86.1 a 2.56 <0.01 CowPGlu,mg/dL 78.0 a 60.5 b 76.2 a 4.94 <0.01 1 SEMrepresentsvariationoffourcow calfpairsforeachtreatment. 2 BeefImprovementFederation(BIF),adjustedweaningweight 3 Plasmaureanitrogen(PUN) 4 Plasmaglucose(PGlu) Withinar owmeanswithoutacommonsuperscriptletterdiffer( P <0.05). Figure7 6.BodyweightofcalvesgrazedonTifton9bahiagrasspastureswithorwithout cowpeaorperennia lpeanutcreepareas SEM=6.6;Week( P <0.001);Species( P >0.67); Weekspecies( P >0.53) 1 Linear(L);quadratic(Q)polynomialcontrastsforweekofgrazingeffects,***( P <0.001); **( P <0.01);*( P <0.05) Table7 1.TheperformanceofcowsandcalvesgrazedonTifton9bahiagrasspastureswithor withoutcowpeaorperennialpeanutcreepareas

PAGE 112

112 BCSthanothercows. Creepgrazing cowpeaincreasedcalfPUNconcentrationsatwk8(Figure thereforeincreasedmeancalfPUNconcentration,but c reepgrazing perennialpeanuthadno similareffects.CowPUNwasnotaffectedbytreatment.CalfPGluconcentrationwasgreatest incalves creepgrazing cowpeafromwk4to8,andthose creepgrazing perennialpeanutonly hadgreaterconcentrationsthan controlcalvesatwk12(Figure7 8).Consequently,onlycalves inthecowpeatreatmenthadgreatermeanPGluconcentrationthancontrolcalves.ThePGlu concentrationsofcowsincontrolorperennialpeanuttreatmentsdecreasedduringthegrazing perio dbutthoseofcowsinthecowpeatreatmentdidnot.Cowsintheperennialpeanut treatmenthadlowermeanPGluconcentrationthantheothers. Experiment2 Pasture HerbageMassandNutritiveValue Themeanherbagemassofbahiagrassandcowpeaw as simila r( P =0.13;1 15 0 216kg and2 290236andDM/ha,respectively),thoughthatofcowpeawasgreaterthanthatof bahiagrassfromwk0to10(Figure7 9).Argentinebahiagrassherbagemassincreasedlinearly fromapproximately1,000kgDM/haintheear lysummertoapeakof1,400kgDM/haatwk8. Cowpeaherbagemassincreasedfrom1,920kgDM/hatoapeakof5,034kgDM/haatwk4,and thenitdeclinedto293kgDM/haatwk12.Slight(7%DM)weedcontaminationwaspresentin thecowpeacreepareaat 8wkbutbywk12,allthecowpeaandweedshadbeenconsumed. Leaf to stemratioofcowpeaincreasedfrom0.9to1.3betweenwk4and8,andthen decreasedto0.7(Figure7 10).TheNDFconcentrationofArgentinebahiagrassincreased linearlythroughth egrazingperiod,whereasthatofcowpeawasrelativelyunchanged(Figure7 11).TheCPconcentrationsofbahiagrassandcowpeadecreasedlinearlyduringthegrazing greaterthanthatofbahiagrass.TheIVTDofbothbahiagrassandcowpea decreased linear ly

PAGE 113

113 a)CalfPUN;SEM=1.5;Week( P <0.65);Species( P <0.05);Weekspecies( P <0.38) b)CowPUN; SEM=1. 9;Week( P <0.25);Species( P <0.36);Weekspecies( P >0.89) Meansateach week withoutacommonsuperscriptletterdiffer( P <0.05). Figure7 7.Plasmaureanit rogen(PUN;mg/dL)concentrationincowsandcalvesgrazedon Tifton9bahiagrasspastureswithorwithoutcowpeaorperennialpeanutcreep areas

PAGE 114

114 Figure7 8.Plasmaglucose(PGlu;mg/dL)concentrationincowsandcalvesgrazedonTifton 9bahiagrasspastureswithorwithoutcowpeaorperennialpeanutcreepareas a)CalfPGlu;SEM=3.7;Week( P <0.001);Species( P <0.003) ;Weekspecies( P <0.01) b)CowPGlu; SEM=6.8;Week( P <0.002);Species( P <0.002);Weekspecies( P >0.09) 1 Linear(L);quadratic(Q)polynomialcontrastforweekofgrazingeffects,***( P <0.001); **( P <0.01);*( P <0.05) Meansateach week wi thoutacommonsuperscriptletterdiffer( P <0.05).

PAGE 115

115 Figure7-9.ChangesinherbagemassofArgentinebahiagrasspasturesandcowpeacreepareasduringthegrazingperiodSEM=458;Species(P>0.13);Weekspecies(P<0.001)1Linear(L)contrastforweekofgrazingeffects,**(P<0.01)Meansateachweekwithoutacommonsuperscriptletterdiffer(P<0.05).Figure7-10.Changesinleaf-to-stemratioofcowpeaduringthegrazing period SEM=0.19;Week(P>0.02)1Quadratic(Q)polynomialcontrastforweekofgrazingeffects,**(P<0.01)

PAGE 116

116 Figure7 11.ChangesinNDFandCPconcentrations(DMbasis)andinvitrotrue digestibility(IVTD)ofArgentinebahiagrasspastureandcowpeacreepareas duringthegrazingperiod a)NDF,%;SEM=2.5;Week( P <0.07);Species( P <0.04);Weekspecies( P <0.18) b)CP,%;SEM=1.4;Week( P <0.001);Species( P <0.02);Weekspecies( P <0.70) c)IVTD,%;SEM=3.7;Week( P <0.003);Species( P <0.02);Weekspecies( P >0.74) 1 Linear(L);quadratic(Q)polynomialcontrastsforweekofgrazingeffects,***( P <0.001); ( P < 0.05) Meansateach week withoutacommonsuperscriptletterdiffer( P <0.05).

PAGE 117

117 period.TheNDFconcentrationofcowpeawasconsistentlylesswhiletheCPconcentrationwas through thegrazingperiod,andthatofcowpea(mean=83%,DMbasis)wasgreaterthanthatof bahiagrass(mean=58%,DM basis).TheCPandNDFconcentrationsoftheconcentratewere lessthanthatofcowpea,buttheIVTDwascomparable. AnimalPerformance Comparedtocontrolcalves,creep fedcalveshadgreaterBWfromwk4to12,whereas creep grazedcalveshadgreater BWfromwk8to12(Figure7 12).Consequently, creepgrazing andfeedingtended( P =0.10)toincreaseweanedcalfBWandcalfADGbutdidnotaffectcow performancemeasures(Table7 2).Creep grazedcalveshadgreaterPUNconcentrationthan creep fed calvesfromwk4to8,andthelatterhadlowerconcentrationsthancontrolcalvesatwk 4(Figure7 13).Consequently,creep fedcalveshadlowermeanPUNconcentrationsthanother calves.Incontrast,creep grazedcowshadthelowestmeanPUNconcentr ations.Cowandcalf PGluconcentrationsdecreasedthroughthegrazingperiod(Figure7 14),butcreep fedcalves hadgreaterconcentrationsthancontrolcalvesatwk12.ControlcowshadgreatermeanPGlu concentrationsthanothercowsduetogreaterco ncentrationsfromwk8to12. Discussion ForageProductionandNutritiveValue Thebahiagrassherbagemassinbothexperimentsisconsistentwiththatfrombahiagrass pastureswithsimilarfixedstockingratesduringsummermonthsinthesoutheasternUnite d States(WilliamsandHammond,1999;Williamsetal.,2002),andthereducedgrowthinthe springisduetolowerrainfallearlyintheseason(Gatesetal.,1999).Themaximumherbage productionofcowpeaisconsistentwiththosefromtrialsinsimilar dryconditions(Minsonetal., 1993;Muir,2002)andtheherbagemassofperennialpeanutwasconsistentwiththatfroma

PAGE 118

118 Item No c reep Concentrate c reep Cowpea c reep SEM 1 P value Calf a ge,d 117 124 107 6.3 0 .20 Initial c alfBW,kg 169 143 137 17.2 0.20 Weaned c alfBW,kg 240 266 254 6.5 0.10 205 dBIF 2 ,adj.wt.,kg 278 289 288 13.6 0.80 Calf83 dADG,kg 1.09 1.40 1.26 0.08 0.10 Cow83 dADG,kg 0.65 0.74 0.58 0.14 0.80 CowBCS 5.7 5.6 5.8 0.09 0.17 C alfPUN 3 ,mg/dL 13.1 a 10.1 b 13.4 a 1.37 0.01 CowPUN,mg/dL 14.6 a 16.1 a 10.5 b 1.06 <0.01 CalfPGlu 4 ,mg/dL 76.8 85.1 82.2 3.58 0.24 CowPGlu,mg/dL 67.5 a 57.9 b 57.8 b 2.28 <0.01 Table7 2.TheperformanceofcowsandcalvesgrazingArgentinebahiagrasspastureswith orwithoutacreepfeedoracowpeacreepgrazingarea Figure7 12.Bodyweightofcalvesgrazed onArgentinebahiagrasspastureswithorwithout cowpeaorconcentratecreepareas SEM=15.0;Week ( P <0.001);Species( P <0.01);Weekspecies( P >0.97) 1 Linear(L)polynomialcontrastforweekofgrazingeffects,***( P <0.001) Meansateach week withoutacommonsuperscriptletterdiffer( P <0.05). 1 SEMrepresentsvariationoffourcow calfpairsforeachtreatment. 2 BeefImprovementFederation(BIF),adjustedweaningweight 3 Plasmaureanitrogen(PUN) 4 Plas maglucose(PGlu) Withinarowmeanswithoutacommonsuperscriptletterdiffer( P <0.05).

PAGE 119

119 a)CalfPUN;SEM=1.8;Week( P <0 .01);Species( P <0.01);Weekspecies( P <0.76) b)CowPUN; SEM=2.1;Week( P >0.63);Species( P <0.006);Weekspecies( P >0.98) Meansateach week withoutacommonsuperscriptletterdiffer( P <0.05). 1 Linear(L);quadratic(Q)polynomialcont rastsforweekofgrazingeffects,***( P <0.001); **( P <0.01);*( P <0.05); (P<0.09) Figure7 13.Plasmaureanitrogen(PUN;mg/dL)concentrationincalvesandcowsgrazedon Argentinebahiagrasspastureswithorwithoutcowpeaorconcentratecreepareas

PAGE 120

120 previousperennialpeanutstudy,whichcontainedsimilarweedcontaminationandgrazing pressure(HernndezGarayetal.,2004). a)CalfPGlu;SEM=6.8;Week( P <0.001);Species( P <0.24);Weekspecies( P <0.50) b)CowPGlu; SEM=3.8;Week( P <0.001);Species( P <0.006);Weekspecies( P >0.60) Meansateach week withoutacommonsuperscriptletterdiff er( P <0.05). 1 Linear(L);quadratic(Q)polynomialcontrastsforweekofgrazingeffects,***( P <0.001); **( P <0.01);*( P <0.05) Figure7 14.Plasmaglucose(PGlu;mg/dL)concentrationincalvesandcowsgrazedon Argentinebahiagrasspastureswit horwithoutcowpeaorconcentratecreepareas

PAGE 121

121 Unlikeperennialpeanut,cowpeahadgreaterherbagemassthanbahiagrassuntilatleastwk 4inbothexperiment s.Thesharpdeclineincowpeaherbagemassfromwk4to12wasdueto grazingpressurebycalves.Inaddition,tramplingmaybeimplicatedbecauseclimbingwarm seasonlegumesaresusceptibletoeffectsoftreadingbygrazinglivestock(PottandHumphre ys, 1983).Incontrast,theherbagemassofperennialpeanutremainedunchangeduntilwk10, indicatingthatperennialpeanutismoretolerantofgrazingthancowpea. TheincreaseinCPconcentrationofperennialpeanutwithtimeinExperiment1is consis tentwithapreviousreportthatattributedthisresponsetofrequentdefoliation(Romeroet al.,1987),whichallowsnewgrowthwithahigherCPconcentrationthanexistinggrowth.The greaterCPconcentrationofcowpeaversusperennialpeanutisexplain edbythegreatertotalleaf mass(mean=1,400250versus90076kgDM/ha,respectively)andgreaterleaf to stem ratioofcowpeafromwk0to4. TheconcentrationsofNDFandIVTDofperennialpeanutwere notchangedastheleaf to stemratiodeclin ed.Thisislikelyduetothedifferentharvest techniquesusedforobtainingtherespectivesamples.Leaf to stemratioratiowasdeterminedon samplescutata5 cmstubbleheightwhereasnutritivevaluewasestimatedonsamplestaken fromthetopoft hecanopy. BahiagrassIVTDdecreasedduringthegrowingseasondueto increasingNDFconcentration.ThehigherIVTDandCPconcentrationandlowerNDF concentrationofthelegumesversusbahiagrassjustifiestheuseofthelegumesassupplements. Themai nweedsinbothcreepareasweregrassessuchascommonbermudagrass( Cynodon dactylon L. )andencroachingbahiagrass.Weedcontaminationinthecowpeacreepareaonly occurredatwk8inbothexperimentsbecausethefullcanopylimitedlightpenetration tothesoil inearlierweeks,andbywk12,weedshadbeencompletelyconsumedwiththecowpea.The

PAGE 122

122 perennialpeanutcreepareacontainedmoreweedsbecauseithada lessercover andaless vigorousgrowthrate. AnimalPerformance Ambienttemperatureinc reasedby8.21.2 Cfrom0600to1000(24.61.3Cat0600 to 32.81.7 Cat1000)duringwk6through12whencalfentrytocreepareaswasmonitored. Consequently,allcattleremainedintheshadefrom0930untiltheeveningwhentemperatures cooled .Calvesspentapproximately7224mingrazingperennialpeanut,5526mingrazing cowpea,and2112minconsumingconcentratebetween0600and0930.Cattlehavebeen showntograzeinadiurnalpattern(VanSoest,1994)especiallyinhot,humiden vironments (Erlingeretal.,1990)buteveninggrazingactivitycouldnotberecordedduetoreasonsoutlined previously.Itwasnotsurprisingthatcalvesspentmoretimegrazingperennialpeanutthan cowpea.Thebitemassofcattledecreaseswithdecre asingforageheight(Hobbs,1999) and grazingtimeincreaseswithdecreasingforageheight(ForbesandHodgson,1985).Perennial peanuthasalowercanopyheightthancowpea,socalveshadtograzelongerto consum ethe samemassofforage. Creepfeedi ngtheconcentratetendedtoincreasecalfADGby0.31kgand creepgrazing cowpeatendedtoincreaseADGby0.21and0.23inexperiments1and2,respectively. Supplementationwithconcentratecreepfeeds(Tarretal.,1994;Prichardetal.,1989;Loyet al., 2002)orcreep grazedhigh qualityforages(OcumpaughandDusi,1981;Bagleyetal.,1997; Corriheretal.,2007)oftenincreasesADGduetoincreasedenergyandproteinsupply.Such supplementsaremostbeneficialafterthethirdmooflactationwh encowmilkproductionhas lessinfluenceoncalfgains(Neville,1962;Robinsonetal.,1978).Therefore,providingdiets withgreaterMEthanthebasalpastureaftercalvesare3 mooldincreasesMEintake. Metabolizableenergyintakedeterminesgrowth rate(Reynolds,1995;Reynoldsetal.,2003)and

PAGE 123

123 thegreaterPGluconcentrationsincalveswithcreepaccesstoconcentrateorcowpeaattheend oftherespectiveexperimentsindicatesthatthesesupplementsincreasedMEintake. Itcouldbepostulatedt hattheADGofcalveswasnotsignificantlyincreasedbycreep grazingorfeedingbecausethenutritionprovidedbythedamsmilkwasadequateforcalf growth.However,becausesometreatmentsincreasedcalfenergyandNstatusandtendedto increasethe irADG,amoreplausibleexplanationisthatinadequatereplicationpreventedgreater detectionofsignificanttreatmenteffects.Therefore,theseexperimentsshouldberepeatedin anotheryrtoverifytreatmenteffects. ThereductioninPGluconcentr ationofcalveswithtimewasduetodevelopmentand increasingfunctionoftherumen(Lambertetal.,1955;McCarthy andKesler ,1956).This reductionwaslessdrasticwhencalvesconsumedcowpeainExperiment1orconcentratein Experiment2,becauseth esesupplementsincreasedtheenergystatusofthecalves. ConcentrationsofPUNingrowinganimalsshouldrangefrom11to15mg/dLtoensure maximumratesofgain(ByersandMoxon,1980).Calvessupplementedwithcowpeainboth experimentsandcontrol calvesinExperiment2hadsufficientPUNconcentrationformaximum growth,buttheothersdidnot.Therefore,c owpeawastheonlysupplementthatprovided sufficientPUNformaximumgrowthandthisledtothetendencyforgreaterADGincalves creep graz ed oncowpeainbothexperiments.Theb loodmetaboliteconcentrationsofcalves indicatethatcowpeawassuperiortoperennialpeanutatimprovingtheenergyandNstatusof calves,butitwasonlysuperiortotheconcentrateatimprovingtheirNstatus. Theseresponses arepartlyduetothegreaterCPconcentrationofcowpeaaswellasthefactthatp erennialpeanut isnotpreferentiallygrazedwhengrassesarepresentuntillateinthegrazingseason(Harrelsonet al.,1994).

PAGE 124

124 Inmostcases,cowPGlu concentrationdeclinedthroughthegrazingseasonbecausethe IVTDofthebahiagrassdecreasedindicatingdecreasedenergysupplyfrompastures.Incontrast, cowsinthecowpeatreatmentinExperiment1maintainedtheirPGluconcentrationsbecause cowpea IVTDvaluesdidnotdecreaseappreciablyduringtheexperiment.Reasonswhythisdid notoccurinExperiment2,orwhycowplasmametaboliteconcentrationsdifferedwithtreatment arenotclear. Creepfeedingtheconcentrateand creepgrazing cowpeatende dtoincreasecalfADGand tendedtoincreasetheirweaningweightsinExperiment2.However,cowpeawastheonly treatmentthatincreasedtheNstatusofcalvesinbothexperimentsandincreasedormaintained theirmeanPGluconcentrations.Therefore,c owpeaisapromisingsupplementforincreasingthe weaningweightofcalves,whichisthemainsourceofincomeincow calfoperations(Prichard etal.,1989). Creepgrazing calvesoncowpeamayalsoprovetobemoreeconomicalthancreep feedingconcentr atesbecauseescalatingfuelcostscontinuetoincreasethepriceofconcentrates. Cowpeashouldbeutilizedincalvesthatareatleast3 mo oldasashort termgrazingsupplement becausecowpeamaynotpersistundercontinuous stock ingforlongperiods. Futureresearch shouldfocusontheeffectsofcreepgrazingcowpeaonmilkproduction,intakeofcreepforage andmilkbythecalf,andpotentialbenefitsofusingcreepfeedingtoreducestressincowsand calvesatweaning.

PAGE 125

125 CHAPTER8 SUMMARY,CONCLUSIONS ANDRECOMMENDATIONS Theoverallobjectiveofthisseriesofexperimentswastodeterminetheeffectsofusing easilyestablishedseeded,warm seasonlegumesthatwillgrow in Floridatoenhancethegrowth ofsheepandbeefc alvesfedbasalbahiagrass( Paspalumnotatum Flgge). Theherbagemass productionandnutritivevalueofcowpea ( Vignaunguiculata (L.)Walp. cv.I ronclay), pigeonpea ( Cajanus cajan (L.)Millsp. cv. Georgia two ),andsoybean ( Glycinemax (L.)Merr. cv. P ioneer97B52) wereinitiallymonitoredinagronomicexperiments.Afterwards, fermentationcharacteristics,nutritivevalue,andaerobicstabilityweremeasuredinhaylages madefromtheselegumesandannual ( Arachishypogaea L. cv. F lorida MDR98) andper ennial peanut ( Arachisglabrata Be nth cv. Florigraze ) .Subsequently,theeffectsofsupplementing haysandhaylagesmadefromtheselegumestobahiagrasshayorhaylageinlambdietswere examinedinmetabolismtrials.Finally,effectsofcreepgrazing cowpeaorperennialpeanutor creepfeedingaconcentrateonthegrowthandbloodmetabolitesofcalveswasmonitored.The followingisasummaryofthemainresultsassociatedwitheachofthelegumes: Asintheotherlegumesilages,considerableproteo lysisoccurredwhenperennialpeanut wasfermentedandsomebutyricacidwasformed.Nevertheless,thehaylagewasaerobically stableandensilingonly moderatelyaffectedthenutritivevalue. Perennialpeanuthayorhaylage supplementationincreasedint akeanddigestibilityofDM,OMandN,andNretentioninlambs. Whensupplementedashay,NDFintake,microbialNproduction,plasmaureaN(PUN)and plasmaglucose(PGlu)concentrationswerealsoimproved. Interestinstoringperennialpeanut ashaylag emayincreasebecauseseasonalrainsinFloridahinderstorageofhayduringsummer months. Althoughperennialpeanutpersistedincreepgrazingareas,itdidnotimprovethe

PAGE 126

126 performanceofcalveswhenitwasgrazed.Otherstudiesindicatethatitdoes nottolerate continuous, close, grazingyear after year(Ortega S.etal.,1992). Theinitialestablishmentcostofperennialpeanutisgreaterthanthoseoftheseededwarm seasonlegumesutilizedinthisseriesofexperiments(Table8 1).However,the annual maintenancecostislessthanthoseofmostoftheannuallegumesanditproducesgreater herbagemass. Therefore,thenetpresentvalueovera20 yr period isgreaterthanthatof cowpea,pigeonpea,orsoybean(Table8 2). Althoughperennialpea nutislesssusceptibleto pests morepersistent ,andmoreeconomicaltoproduce inthelongterm thantheseededwarm seasonlegumes(Table8 3 ),theexpenseandprotractedestablishmentofperennialpeanutmake seededwarm seasonlegumesamoredesirabl eoptionforsomeproducers. Ensilingannualpeanutresultedinconsiderableproteolysisandsomebutyricacid production,buthadminimaleffectsonnutritivevalue.Whensupplementedashay,annual peanutincreasedintakeanddigestibilityofDM,OMa ndN,Nretention,microbialNproduction, andPUNoflambs.Annualpeanuthaylagesupplementationhadsimilareffectsandproduced greaterimprovementsthanperennialpeanuthaylageformostoftheseperformancemeasures, indicatingthatannualpeanutma yhavemorepromiseasasupplementwhenensiledversuswhen storedashay. Theinitialestablishmentcostandsusceptibilitytopestsofannualpeanutiscomparableto thatofcowpeaandsoybean(Table8 1 ; 8 2 ).Annualpeanuthassimilarforagequalit y to perennialpeanut (Table8 2) ,but ithasalowernetpresentvalueandit ismoresusceptibleto pests(Table8 3 ).Currently,nofungicidesarelabeledforuseonannualpeanutproducedfor livestockfeed.This situationmayneedtoberectifiedto allowlivestockproducerstoexploitthe promiseofthisforage.

PAGE 127

127ForageSeedorsprigcost,$Seedorsprigrate/haInitialestablishmentcost1,$/haAnnualmaintenancecost2,$/haHerbagemass,kgDM/yrNo.ofbales3ha-1yr-1Costofhaybaling4,$ha-1yr-1Costofhaylagebaling5,$ha-1yr-1 Perennialpeanut3.00/bu198bu1,72053010,00070980770 Annualpeanut1.21/kg20kg6405308,00057798627Cowpea1.94/kg56kg7406605,00036504396Pigeonpea4.41/kg56kg9008208,80063882693Soybean1.94/kg56kg7406608,40060840660 Table8-1.Costsofproducingperennialpeanut(cv.Florigraze),annualpeanut(cv.FloridaMDR98),cowpea(cv.Ironclay),pigeonpea(cv.Georgiatwo),andsoybean(cv.Pioneer97B52)forage,hay,orhaylageproductionin2006 1 Includesseed,fertilizer(330kg/ha0-20-40ratioofN:P2O5:K2O),1,800kg/halime,herbicide,machinery,labor,andestimatedinterestonmonetaryinvestment2Includesseedforcowpea,pigeonpeaandsoybean,fertilizer(330kg/ha0-20-40ratioofN:P2O5:K2O),herbicide,machinery,labor,andestimatedinterestonmonetaryinvestment,butnotlimebecauseitshouldberequiredevery2to3yr3Estimatedfromsmall(140kg)roundbalesutilized4Estimatedfrom$14.00chargeperbalefortwine,machinery,andlabor5Estimatedfrom$11.00chargeperbalefortwine,plasticwrap,machinery,andlaborEquationsfromHewitt,2006andPrevatt,2008

PAGE 128

128ForageHayproductionnetpresentvalue1,$/haHaylageproductionnetpresentvalue1,$/ha Perennialpeanut9,32011,490 Annualpeanut8,23010,170 Cowpea1,4402,660 Pigeonpea6,6608,800 Soybean7,6909,730 Whenpigeonpea,cowpea,andsoybeanweretestedforherbagemassproductionandnutritivevalueinagronomicplots,pigeonpeaproducedthegreatestherbagemass,andsoybeanproducedgreaterherbagemassthancowpea.However,soybeanandcowpeahadsimilarnutritivevaluesthatweregreaterthanthatofpigeonpea.Thehighyieldpotentialandnutritivevalueofsoybeanindicatethatitcanbeusedtoproducerelativelylargequantitiesofqualityforage.Whensupplementedashay,soybeanimprovedDM,OM,NDF,andNintakesaswellasNdigestibilityandretentionoflambs.Soybeanhaylagewasnotevaluatedbecauseitwasnotsuccessfullyestablishedintheyrthehaylageexperimentswereconducted. Althoughsoybean ismoreexpensivetoproducethanperennialorannualpeanutinthe secondandsubsequent years (Table8-1;8-2),itismoreeconomicaltoproducethantheother seededwarm-seasonlegumes. Thecultivarutilizedinthisseriesofexperimentsis resistanttomanypests(Table8-3)and glycophosphatewhichsimplifiesmanagementofthis forage.Table8-2.Netpresentvaluesummaryforperennialpeanut(cv.Florigraze),annualpeanut(cv.FloridaMDR98),cowpea(cv.Ironclay),pigeonpea(cv.Georgiatwo),andsoybean(cv.Pioneer97B52)forage,hay,orhaylageproductionovera20-yrhorizon 1 Expensesincluded7%interestrateand$80liming(1,800kg/ha)inalternateyears;profitincluded$37valueof140kgroundbale

PAGE 129

129ForageSeedorsprigavailabilityInoculationrequiredForagequalityPestissuesPersistence,yr PerennialpeanutLocallyNoHighOnlyknownpestispeanutstuntvirus20+ AnnualpeanutLocallyYesHighSusceptibleto:earlyleafspot,spidermitesResistantto:lateleafspotRelativelymoreresistancethanothercultivarsto:stemrot,rust,rootknotnematode5+ CowpeaWidespreadYesModerateifharvested,highifgrazedSusceptibleto:powderymildew,anthracnose,fusariumwilt,aphids,leafminers,soybeanloopers,Resistantto:root-knotnematode1 PigeonpeaLimitedYesLowSusceptibleto:fusariumwilt,soybeanloopers,1 SoybeanWidelyavailableintheSoutheasternUnitedStatesYesModerateSusceptibleto:phytophthorarot,cystnematoderace14,soybeanloopers,rustResistantto:frogeyeleafspot,cystnematoderace3,southernroot-knotnematode1 Table8-3.Foragemanagementcharacteristicsofperennialpeanut(cv.Florigraze),annualpeanut(cv.FloridaMDR98),cowpea(cv.Ironclay),pigeonpea(cv.Georgiatwo),andsoybean(cv.Pioneer97B52)InformationcompiledfromChapters3,4,5,6,and7;Karungietal.,2000;GorbetandShokes,2002;Frenchetal.,2006;Woodruff,2007

PAGE 130

130 Althoughcowpeaha dlowerDMyieldsthanpigeonpeaandsoybeanduringthegrowing season,cowpeaconsistentlyhadgreaterleaf to stemratioandnutritivevaluethanpigeonpea, andhadgreatervaluesthansoybeanforpartofthegrowingseason.Thissuggeststhatwhen graz ed,cowpeahasgreaterpotentialtoimprovelivestockperformancethansoybeanor pigeonpea.Thiswasconfirmedinthecreepgrazingexperimentwherecalvescreep grazed on cowpeahadsimilarperformancetothosefedacreepconcentrate,andgreaterperfo rmancethan thosecreep grazedonperennialpeanutorthosereceivingnocreepfeed.Therefore,creep grazingcalvesoncowpeaisapromisingstrategyforincreasingweaningweightsorgrowthrates ofcalves.However,manyfactorsinfluenceaproducers decisiontocreepgraze,suchas climate,costsassociatedwithplantingandfencing,anddesiretomanagepasturesintensively. Profitmarginsofcow calfoperationsaresmall(USDA,2001),thereforethesefactorsshouldbe takenintoconsiderationbefor eproducerscreepgrazecalvesoncowpea. Inspiteoftheindeterminategrowthofcowpeawhichallowsittoitregrowafter defoliation,itdidnottoleratecontinuous stock ingandtreadinginthecreepgrazingexperiment. Therefore,cowpeaismoresuita bleforuseas a proteinbankorfor creepgrazing thanas the bas e pasture.Whencowpeawasensiled,considerableproteolysisoccurred,thenutritivevalue decreased,andthefermentationwasinefficient.Therefore,cowpeaislesssuitableforensiling thantheother warm season legumesthatwereexamined.Whensupplementedashayor haylagetobasalbahiagrassdiets,lambshadincreasedDM,OM,andNintakes,Ndigestibility, andNretention.Buttheseresponseswerelesspronouncedthanthosefroma nnualorperennial peanuthaylageorhay. Itisalsopertinenttonotethatcowpeaislesseconomicaltoproduce as hayorhaylage thanmostoftheotherwarm seasonlegumes(Table8 1 ; 8 2 ).

PAGE 131

131 Theearly maturingcultivarofpigeonpea producedthegr eatest herbagemassinthe agronomicexperimentbutalsohadthelowestnutritivevalue.Althoughalargeamountof herbagemassisproducedwhenpigeonpeaisgrown,onlytheleaveshavesufficientIVTDto provideadequatenutritiontogrowingruminantlivestock .Therefore,whenpigeonpeaforage wassupplementedashaytobahiagrassbasaldiets,DM,OM,andNDFintakewerenotimproved andwhenfedashaylage,therespectiveintakesandOMdigestibilityweredecreased. Nevertheless,pigeonpeahaysupplementatio nslightlyimprovedNintake,retentionand digestibilitythoughpigeonpeahaylagedidnot.Theseresultsconfirmedthathaysandhaylages madefromthisearly maturingpigeonpeacultivararenotidealsupplementsforgrowing ruminants.The relatively hi ghcostofproduction,lowquality,andlimitedseedavailability indicatethatpigeonpeaisnota promising forageforlivestockproducers(Table8 1 ; 8 2 ; 8 3 ). Toenhancethenutritivepotentialofpigeonpea,itshouldbeharvestedtoastubbleheight above 40 cm,butthisisdifficulttoachievewithconventionalforagemowers.Therefore,the pigeonpeacultivarevaluatedmaybemostsuitedforuseasabrowse forsmallruminantsthat selectivelyfeedonleaftissue. Perennialandannualpeanutarer ecommendedasthemostpromisinglegumesforthe southeastbecauseoftheirgreater netpresentvalue, herbagemass,highquality,andpersistence whenproperlymanaged.Soybeanisa moreeconomically viablehayorhaylagelegume supplement thancowpeaor pigeonpeabecauseofitsmoderatelyhighnutritivevalueand relativelyhighyields. Becauseofthelowyieldsandhighcostofcowpeaproduction,itwould bemoreeconomicaltoutilizecowpeaforgrazing. Thehypothesisthat seededwarm sea sonlegumesc anbeusedlike perennialpeanut to increasenutrientstatusandutilization,andweightgainincattleorsheepfedbasalbahiagrass

PAGE 132

132 dietswasvalidatedformostofthelegumesexamined.Theanimalresponsesinthisseriesof experimentsindicatethatper ennialandannualpeanut,soybean,andcowpeaarepromising supplementstoimprovetheproductivityoflivestockinFloridaandotherlocationswithsimilar climates.Thesewarm seasonlegumesshouldbeparticularlyattractivetoproducersbecausethe esc alatingpriceoffuelhasincreasedthepriceofimportedalfalfa( Medicagosativa L. )andother concentratesupplements. Futureresearchshoulddeterminetheeconomicvalueofusingthesewarm seasonlegumes assupplementsinsteadofconcentratesoral falfa.Theoptimalinclusionrateoftheselegumesin bahiagrassbasalrationsalsoneedstobeestablished.Thedegradationrateoftheproteinand carbohydratesinthelegumesneedstobedeterminedtofacilitatetheiruseinintensiveruminant product ionsystems. Furtherstudiesshouldalsoexamineeffectsofaddingbacterialorchemical additivesorfermentablecarbohydratesourcesonthefermentationofthelegumes.Littleis understoodaboutthemechanismbywhich creepgrazing improvescalfperfo rmance,therefore, researchfocusingon effectsofcreep grazingonmilkproductionbythecow,intakeofcreep foragebythecalf,andcowandcalfimmunestatusisrecommended.

PAGE 133

133APPENDIXASLIDINGSCALEFORURINECOLLECTIONSFORCHAPTER4Volumeofurinecollected(mL)%Sub-sampled 0-500100 501-120050 1201-250020 Greaterthan250010 TableA-1.Slidingscaleforurinecollections

PAGE 134

134 APPENDIXB CONDENSEDTANNINSME THODFORCHAPTER4 PurificationofQuebrachoTannin PurificationisbasedonthemethodofAsquithandButler(1985)andmodifiedby Hagerman(1994).ThisspecificmethodwasadaptedfortheRuminantNutritionLab, Departmen tofAnimalSciences,UniversityofFlorida,Gainesville. Reagents: 80%ethanol:80mLabsoluteethanoltovolumewithdistilledH 2 Oin100mL volumetric SephadexLH 20:GEHealthcareLifeSciences,Piscataway,NJ 95%ethanol 50%aqueousacetone:50mL acetonetovolumewithdistilledH 2 Oin100mL volumetric Preparation : Quebracho 1. Weigh1gofquebrachointoa25mLvolumetricflask.Add10mL80%ethanol. 2. Vortexuntilsolidnolongeradherestothebottomoftheflask. 3. Placeinrefrigerator,without movingfurther,overnight. Sephadex 1. SephadexLH 20ispreparedin80%ethanol.Swellabout25gofSephadexin80% ethanoltomake100mLofslurry.Stirthebeadsgentlywithastirringrodtofacilitate moistening,butbegentlesoyoudonotbreak thebeads. 2. Allowtosettleanddecantoffsupernatantandfines. 3. Repeat3times. 4. Storetightlycappedintherefrigerator. NOTE:Thisisveryexpensivematerialandcanbereusedindefinitelyifhandledproperly. Regenerateafterfiltrationbycomplete lywashingawaytheacetonewith80%ethanolandstore tightlycappedintherefrigerator.BeforereusingoldSephadexLH 20,severalwashesshouldbe carriedoutwith80%ethanolasdescribedabovetoremovefinesandresidualadsorbed materials. Sephad exLH 20constitutedwith80%ethanolbindstanninallowingothermaterialstofilterout. Thesubsequentrinsingwith50%acetoneallowsthehydrophilictannintobindtotheaqueous fractionandberemovedfromthefiltrate. Extraction : 1. Filterthequeb rachosuspension(liquidfraction)throughWhatman#40(medium) filterpaperusingaBuchnerfunnelandgentlevacuumifnecessary. 2. Addthefiltrateto100mLofSephadexLH 20in80%ethanol.Stirfor3min(no longerorabrowntardifficulttoremove fromtheSephadexwillform). 3. AddmaterialtoaBuchnerfunnellinedwithwetWhatman#40paper.

PAGE 135

135 4. WashtheLH 20with95%ethanol. Allowfresh95%ethanoltoequilibratewith Sephadexandgentlevacuumisacceptable.DonotstirastheSephadexwillbe fil teredout 5. Blankaspectrophotometertothe95%ethanolandreadtheabsorbanceofthefiltrate at280nm.BecausethisisthemiddleoftheUVspectrumyoumustusequartzorUV transparentcrucibles.WhenthefiltrateiscolorlessandtheSephadexisa darkruddy, browncolor, checkthefiltrateandcontinuerinsinguntilthefiltrateabsorbance approaches0.Ethanolrinsescanbediscarded. 6. WashtheSephadexwith50%aqueousacetonecombiningandsavingthesewashes. ContinuetowashuntiltheSep hadexiswhiteandtheeluateisnearlycolorless. 7. Re constitutetheSephadexin80%ethanolandrepeatformoresamplestoobtainthe desiredfinalextract.Youmayrefrigeratethefiltrateovernightinabrownbottleif youdonothavetimetocomplete. 8. Evaporatetheacetonewashestocompletelyremovetheacetone.Placethebottleina waterbathheatingto30 C(nowarmer)withahoseflushingCO 2 orNgasacrossit. 9. Thismaytakemorethan1d.Repeat,storingsampleindarkbottleinrefrigerator w hennotevaporating,untilacetoneisremoved(waftingforsmellisthebest indicator). 10. Freezetheaqueousfractionovernightandthenplaceinthefreezedryer.Thefinal resultisfluffy,tan brownpowder.Thisshouldbestoredinthefreezer.Thiss hould provideenoughpurifiedfractionfortwosetsofstandardsasdescribedfurther. CondensedTannin(CT)Extraction ThisprocedureisbasedonthatofTerrilletal.(1992). Reagents: 70%Acetone(v/v)indistilledH 2 O Diethylether(Ether) Method: 1. Weigh0.25g(0.23to0.28g)sampledirectlyintotesttubeintriplicate.Recordthe weight. 2. Add5mLof70%aqueousacetoneandvortexfor10s. 3. Add2mLethertoeachtubeandvortexforanadditional10s. 4. Centrifugefor15minat 4 Cand3,000 g 5. Removebyaspirationanddiscardthegreenaqueouslayer(upperacetone:etherphase) intoetherwastebottle(emptyaluminumetherbottlelabeledashazardouswaste)using disposablepipettes. 6. Decantthelowerphaseintoanidenticallylabeledtubeta kingcarenottoloseanysample ifithasnotformedasolidpellet. 7. Repeattheextractiontwice(totalof3times).Youmayhavetorepeatmorethan3times ifyourextractisstillyellow;ifthisisthecaserepeatuntilnearlycolorless.Ifasolid pellethasformedthatwillnotdisintegratebyvortexingfragmentitusingaglassrod. NOTE:Younowhave2samplesforeachforagesample. LiquidSample Extractable CT

PAGE 136

136 1. Removeresidualacetone:etherofextractinawaterbathheatedto40 Candundera ir stream(CO 2 orNgas)for2 4h.Makesureallsolventisremoved. 2. Centrifudgesolutionfor15minat 4 Cand3,000 g .Pour4.5mLofsupernatant(this representsallthewaterusedfor3extractions)(ifyouhavelessthan4.5mLrecordthe amoun tpipetedintothevolumetric)into10mLvolumetricflaskandbringtovolume withDIwater.Maybestoredfor24hrefrigerated,otherwiseanaliquotmaybeplaced inavialandfrozenforfutureuse. SolidSample Bound CT 1. Drytheresidueforabout5mi ninevaporatorat40 Cinafumehood.Makesureall solventisremoved. 2. Maybestoredfor24hrefrigerated,otherwisefreezeforfutureuse. ExtractableCondensedTanninAnalysis Reagents: Butanol HCl:95mLofn butanolwith5mLofconcentratedHCl. Thisneedstobe freshlyprepared Extractedquebrachotanninstandards 70%acetone:70mLacetonetovolumewithdistilledH 2 Oin100mLvolumetric Standard Preparation: 1. Dissolve0.025gpurifiedquebrachoin25mLofdistilledH 2 Otomakestocksolu tionof 1mg/mL(1,000ppm)representing10%CT. 2. Makeaserialdilutiontoobtain1,2,4,6,8,10%CT. a. 1%=0.5mLstocktovolumewithdistilledH 2 Oin5mLvolumetric b. 2%=1.0mLstocktovolumewithdistilledH 2 Oin5mLvolumetric c. 4%=2.0mLstock tovolumewithdistilledH 2 Oin5mLvolumetric d. 6%=3.0mLstocktovolumewithdistilledH 2 Oin5mLvolumetric e. 8%=4.0mLstocktovolumewithdistilledH 2 Oin5mLvolumetric f. 10%=stocksolution Method: 1. Pipette1mLoftanninsupernatantintoscrew capglasstesttubes.Dothisinduplicate andplaceeachsetindifferenttesttuberacks.(Onerackisunheatedandservesasa standardforeachheatedsample). 2. Pipette1mLofstandard(0.0(distilledH 2 O),1,2,4,6,8,and10%)intoscrewcapgl ass testtubesplacingintheracktobeputinthewaterbath. 3. Add6mLofbutanol HClreagenttoeachtube. 4. Vortexthetubesandplaceonesetplusstandardsinwaterbathpreheatedto97 100 C. Placeglassmarblesonthetubes.Heat75min. 5. Cooltubes onice. 6. Usingdisposablepipettes,pipettestandardsintocuvettesandreadabsorbanceat550nm, blankingthespectrophotometerwiththe0%standard.Theunheatedsamplesarethe blankforeachheatedsampleandshouldbereadandrecordedsequentially. (i.e.back corrfor0%standard,readstandards,readfirstunheatedsample,thenfirstheated sample,andsoon.)

PAGE 137

137 a. Ifabsorbanceisgreaterthan0.7,dilutetheextractwith70%acetoneuntil absorbancedoesnotexceed0.7(1:4isgoodtobeginwith). Notealldilutions. 7. Developregressionequationforstandardcurve.Subtractabsorbanceofeachunheated samplefromthatofeachheatedsample. Calculations: EstimatetheCTconcentration(%)fromthestandardregressionequationusetheoptical densit yreadingsoftheunheatedsamplesubtractedfromtheheatedsample. DilutioncorrectedCT(%)=CT(%)2.22(dilutionofextractinwater) CT(%,DMbasis)=DilutioncorrectedCT(%)SampleDM BoundCondensedTanninAnalysis Reagents: Butanol HCl: 95mLofn butanolwith5mLofconcentratedHCl.Thisneedstobe freshlyprepared Extractedquebrachotanninstandards 70%acetone:70mLacetonetovolumewithdistilledH 2 Oin100mLvolumetric Method: 1. Add1mLof70%acetoneand6mLbutanol HCl reagenttotheresidue. 2. Vortexthetubesandplaceinwaterbathpreheatedto97 100 C.Placeglassmarbleson thetubes.Heat75min. 3. Cooltubesoniceandcentrifugefor10minat 4 Cand3,000 g 4. Utilizingthesamestandardsasfortheextractable tanninanalysisreadtheabsorbanceat 550nmofthesupernatantpipettedwithdisposablepipettesintothecuvette. a. Ifabsorbanceisgreaterthan0.7,dilutetheextractwith70%acetoneuntil absorbancedoesnotexceed0.7(1:4isgoodtobeginwith).N otealldilutions. 5. Developregressionequationforstandardcurve.EstimatethePAconcentrationfromthe regressionequationtakingnoteofanydilutionsandthesampleweight.Expressresults asg/kgDM. Calculations EstimatetheCTconcentration(%) fromthestandardregressionequation. SampleCT(%)=CT(%)Originalsampleweight DilutioncorrectedCT(%)=SampleCT(%)Dilution CT(%,DMbasis)=DilutioncorrectedCT(%)orSampleCT(%)ifnodilutionmade SampleDM TotalCT(%)= ExtractableCT+BoundCT

PAGE 138

138 APPENDIXC PURINEDERIVATIVESM ETHODFORCHAPTERS4 AND6 ConversionofXanthine,HypoxanthineandUricAcidtoAllantoin Procedureadaptedfrom Fujiharaetal.(1987) Reagants: Stockallantoin:1gallantoin/1LdistilledH 2 O NaOH H 2 SO 4 Glycinebuffer: 5.029mLGlycine/100mLdistilledH 2 OandpHadjustedto7.7with NaOH andH 2 SO 4 Uricase:5units/12mLGlycinebuffer Xanthineoxidase:5units/12mLGlycinebuffer 0.6MNaOH HCl 2,4 Dinitrophenylhydrazinesolution:0.133g2,4 Dinitrophenylhydrazin e/100mL 2MHCl 2.5MNaOH Preparation: 1. Dilute1 mL urinewith49 mL ofdistilledH 2 O. 2. MeasurethepHandadjustwithNaOHandH 2 SO 4 toapHofexactly8.0. Theprepared enzymesandurinedilutionsshouldbestoredfrozen( 20 C)untilanalysis. 3. Prepare allantoinstandards:10,20,30,40and50mg/Lwith10,20,30,40,and50mL allantoinstocksolutionto100mLvolumewithdistilledH 2 Orespectively. 4. Placesamples,standards,andenzymes(uricaseandxanthineoxidase)intherefrigerator thenightbe fore. Method: 1. Turnonthewaterbathtoheatto100 C. 2. Add2.5mLdilutedurinetoatesttube.Add150lxanthineoxidasetothedilutedurine. Leaveatroomtemperature,for2h. 3. After2h,add150luricasetothedilutedurine.Leaveatroomtemp eratureforanother 2h. 4. After2hturnonthespectrophotometerandsetto520nm. 5. Add1.5mLof0.6MNaOHtoeachtesttubeandclosethecaptightly. 6. Incubatethetesttubesinthe100Cwaterbathfor15min. 7. Removefromwaterbathandadd1mLof theHCl 2,4 Dinitrophenylhydrazinesolution toeachtesttube. 8. Returntothewaterbathfor4min. 9. Removeandruncoldwateroverthetubes.Oncecooltothetouch,add5mL2.5M NaOHandshakeeachtube. 10. Readat520nmonthespectrophotometer.

PAGE 139

139 Calcul ations Calculateallantoin(mg/L)indilutedurinesamplebasedonregressionofstandardcurve. UrinaryoutputofpurinederivativesinsheepcalculatedbyChenetal.(1992). Allantoin(g/d)=[allantoininurinesamples(mg/L)totalurineoutput(mL/ d)] 1,000,000 TotalPurineDerivatives(mmol/d)=Allantoin(g/d)0.158 MicrobialPurineDerivatives(mmol/d)=TotalPurineDerivatives(mmol/d)0.84 MicrobialNitrogenProduction(g/d)=MicrobialPurineDerivatives(mmol/d)0.727 Digest ibleOrganicMatterIntake=kgOrganicMatterIntakeOrganicMatter Digestibility MicrobialEfficiency=MicrobialNitrogenProduction(g/d)/kgDigestibleOrganicMatter Intake

PAGE 140

140 APPENDIXD SASCODESUSEDFORC HAPTER3 TheSAScodesusedtoanalyze herbagemass,leaf to stemratio,and CP,NDF,andin vitrotruedigestibility(IVTD) ofleaf,stemandwholeplanttissue arepresentedhere. D ata LegumeP lot T rial; I nput YrForageS pecies$B lock Replicate W eekAfter P lanting HerbageMassLeaftostem WholeplantCPWholeplantNDFWholeplantIVTDStemCPStemNDFStemIVTDLeafCP LeafNDFLeafIVTD ; C ards; P roc M ixed D ata= LegumePlotTrial ; C lass YrForageSpeciesWeekAfterPlantingB lock; M odel HerbagemassLeaftostemWholeplantCPWholeplantNDFWholeplantIVTDStemCP StemNDFStemIVTDLeafCPLeafNDFLeafIVTD=YrForageSpeciesWeekAfterPlanting ForageSpecies*WeekAfterPlantingForageSpecies*YrWeekAfterPlanting*Yr ForageSpecies*WeekAfterPlanting*Yr ; R andom BlockBlock*Yr ; R un; P roc M ixed D ata= LegumePlotTrial; C lass ForageSpeciesWeekAfterPlantingB lock; M odel HerbagemassLeaftostemWholeplantCPWholeplantNDFWholeplantIVTDStemCP StemNDFStemIVTDLeafCPLeafNDFLeafIVTD=ForageSpeciesWeekAfter Planting ForageSpecies WeekAfterPlanting ; R andom B lock; L smeans ForageSpecies WeekAfterPlanting / P diff; R un; Polynomialcontrastswereusedtodeterminetrendsovertime,eachforagewasentered intoanindividualSASfileandthefollowingaretheSASc odesused. D ata LegumePlotTrial ; O ptionformdlim=*; I nput YrForageSpecies $ BlockReplicate W eekAfter P lanting HerbageMassLeaftostem WholeplantCPWholeplantNDFWholeplantIVTDStemCPStemNDFStemIVTDLeafCP LeafNDFLeafIVTD ; C ards; P roc M ixed D ata= Le gumePlotTrial ; C lass Block WeekAfterPlanting ; M odel HerbageMassLeaftostemWholeplantCPWholeplantNDFWholeplantIVTDStemCP StemNDFStemIVTDLeafCPLeafNDFLeafIVTD= W eekAfter P lanting ; R andom Block ;

PAGE 141

141 C ontrast'linear' WeekAfterPlanting 7 5 3 113 57; C ontrast'quadratic' WeekAfterPlanting 71 3 5 5 317; C ontrast'cubic' WeekAfterPlanting 7573 3 7 57; R un;

PAGE 142

142 APPENDIXE SASCODESUSEDFORC HAPTER4 TheSAScodesusedtoanalyze DM,OM,CP,NDF,ADF,lignin,invitrotruedigestibility (IVTD),extractablecondensedtannin(ECT)andboundcondensedtannin(BCT)offorages are presentedhere. D ata M et abolism200 5HayD iet s ; I nput PeriodF orage Species$DMOMCPNDF ADFLig nin IV T DE C TB C T; C ards; P roc M ixed Data=Metabolism2005HayDiets ; C lass PeriodF orage Species ; M odel DMOMCPNDF ADFLig nin IV T DE C TB C T =F orage Species ; R andom P eriod; L smeans F orage Species / P diff; R un; The SAScodesusedtoanalyzeDM,OM,NDFandNi ntake sand digestibilit ies ,N excretionandretention, microbialprotein(MP) parameters, plasmaureanitrogen( PUN ) and plasmaglucose( PGlu ) arepresentedhere. D ata Metabolism2005I ntake DigestibilityNparametersandBloodMetabolites ; I nput P er iod SheepIDTreatment $ DMintakeOMintakeNDFintakeNintakeDMdigestibility OMdigestibilityNDFdigestibilityNdigestibilityFecalNUrinaryNNretentionPurineDerivative MicrobialNDigestibleOMIntake MicrobialEfficiencyPUNPGlu ; C ards; P roc M ixed D ata= Metabolism2005I ntake DigestibilityNparametersandBloodMetabolites ; C lass SheepID PeriodTreatment ; M odel DMintakeOMintakeNDFintakeNintakeDMdigestibilityOMdigestibility NDFdigestibilityNdi gestibilityFecalNUrinaryNNretentionPurineDerivativeMicrobialN DigestibleOMIntakeMicrobialEfficiencyPUNPGlu=Trea t meant P er iodTreatment*P er iod ; R andom SheepID ; L smeans Treatment / P diff; R un; The SAScodesusedto analyzingruminalfluidpH,NH 3 NandVFA arepresentedhere. D ata Metabolism2005RuminalFluidParameters ; I nput SheepID Treatment $ H pHNH3NTotalVFAAcetatePropionateIsobutyrateButyrate IsovalerateValerateAcetatePropionateRatio; C ards;

PAGE 143

143 P roc M ixed D ata= Metabolism2005Ruminal FluidParameters ; C lass SheepIDTreatmentH ; M odel pHNH3NTotalVFAAcetatePropionateIsobutyrateButyrateIsovalerateValerate AcetatePropionateRatio = TreatmentHTreatment H ; R epeated H / S ubject= SheepID ( Treatmen t) T ype =AR (1); R andom SheepID ; L sme ans Treatment / P diff; R un;

PAGE 144

144 APPENDIXF SASCODESUSEDFORC HAPTER5 TheSASCodesusedtoanalyzeDM,OM,CP,NDF,andinvitrotruedigestibility(IVTD) offoragespriortoandpostensilingandoffermentationcharacteristics,microbialcountsand aerobicstabilityispresentedhe re. D ata LegumeH aylage NutritiveValueFermentationCharacteristicsandAerobicStability ; I nput ForageSpecies$R ep licate Forage DM ForageOMForageCPForageNDFForageIVTD EnsiledDMEnsiledOMEnsiledCPEnsiledNDFEnsiledIVTDpHAmmoniaNitrogenLactate Acet atePropionateButyrateTotalVFALactateAcetateRatioYeastsMoldsAerobicStability ; C ards; P roc M ixed D ata= LegumeH aylage NutritiveValueFermentationCharacteristicsandAerobic Stability ; C lass ForageSpeciesR ep licate ; M odel Forage DM ForageOMForage CPForageNDFForageIVTDEnsiledDMEnsiledOM EnsiledCPEnsiledNDFEnsiledIVTDpHAmmoniaNitrogenLactateAcetatePropionate ButyrateTotalVFALactateAcetateRatioYeastsMoldsAerobicStability ; C ards= F orage Species ; L smeans Forage / P diff; R un;

PAGE 145

145 APPENDIXG SASCODESUSEDFORC HAPTER6 TheSAScodesusedtoanalyze DM,OM,CP,NDF,ADF,lignin,andinvitrotrue digestibility(IVTD)offorages arepresentedhere. D ata M et abolism2007HaylageD iet s ; I nput PeriodF orage Species$DMOMCPNDF ADFLig nin IV T D; C ards; P roc M ixed Data=Metabolism2007HaylageDiets ; C lass PeriodF orage Species ; M odel DMOMCPNDF ADFLig nin IV TD=F orage Species ; R andom P eriod; L smeans F orage Species / P diff; R un; TheSAScodesusedtoanalyzeDM,OM,NDFandNintakesa nddigestibilities,N excretionandretention,microbialprotein(MP)parameters,plasmaureanitrogen(PUN)and plasmaglucose(PGlu)arepresentedhere. D ata Metabolism2007I ntake DigestibilityNparametersandBloodMetabolites ; I nput P er iod SheepIDTr eatment $ DMintakeOMintakeNDFintakeNintakeDMdigestibility OMdigestibilityNDFdigestibilityNdigestibilityFecalNUrinaryNNretentionPurineDerivative MicrobialNDigestibleOMIntakeMicrobialEfficiencyPUNPGlu ; C ards; P roc M ixed D ata= Metabolism2007I ntake DigestibilityNparametersandBloodMetabolites ; C lass SheepID PeriodTreatment ; M odel DMintakeOMintakeNDFintakeNintakeDMdigestibilityOMdigestibility NDFdigestibilityNdigestibilityFecalNUrinaryNNretentionPurineDerivativeMicrobialN Digest ibleOMIntakeMicrobialEfficiencyPUNPGlu=Trea t meant P er iodTreatment*P er iod ; R andom SheepID ; L smeans Treatment / P diff; R un; The SAScodesusedto analyzingruminalfluidpH,NH 3 NandVFA arepresentedhere. D ata Metabolism2007RuminalFluidParamete rs ; I nput SheepID PeriodTreatment $ H pHNH3NTotalVFAAcetatePropionateIsobutyrate ButyrateIsovalerateValerateAcetatePropionateRatio; C ards; P roc M ixed D ata= Metabolism2007RuminalFluidParameters ;

PAGE 146

146 C lass SheepIDPeriodTreatmentH ; M odel pHNH3N TotalVFAAcetatePropionateIsobutyrateButyrateIsovalerateValerate AcetatePropionateRatio = TreatmentHPeriodTreatment HTreatment*PeriodH*Period Treatment*H*Period ; R epeated H / S ubject= SheepID ( Treatmen t) T ype =AR (1); R andom SheepID ; L smeans Tre atment / P diff; R un;

PAGE 147

147 APPENDIXH SASCODESUSEDFORC HAPTER7 TheSAScodesusedtoanalyze herbagemass leaf to stemratio,NDFandCP concentrations andin vitrotruedigestibility (IVTD)offorages arepresentedhere. D ata G razing ForageAnalyses ; I nput BlockP addock WeekForageS pecies$H erbage M assLeaftostemNDFCPIVTD ; C ards; P roc M ixed D ata= G razing ForageAnalyses ; C lass BlockP addock WeekForageS pec ies; M odelH erbage M assLeaftostemNDFCPIVTD=W eek ForageSpeciesW eek* ForageS pecies; R andom BlockBlock*ForageS pecies; L smeans W eek* ForageS pecies / P diff; R un; Polynomialcontrastforherbagemass,leaf to stemratioandnutritivevaluechangesover t imewerecompletedbycreatingandindividualSASfileforeachforagespeciesandtheSAS codesusedarepresentedhere. D ata TrendsOverTimeG razing ForageAnalyses ; I nput BlockP addock WeekForageS pecies$H erbage M assLeaftostemNDFCPIVTD ; C ards; P ro c M ixed D ata= TrendsOverTimeG razing ForageAnalyses; C lass WeekB lock; M odelH erbage M assNDFCPIVTD=W eek; R andom B lock; C ontrast'linear' W eek 0 .57 0 .38 0 .190 0 .19 0 .380.57; C ontrast'quadratic' W eek 0 .550 0 .33 0 .44 0 .330 0 .55; C ontrast'c ubic' W eek 0 .40 0 .40 0 .400 0 .40 0 .40 0 .40; R un; P roc M ixed D ata= TrendsOverTimeG razing ForageAnalyses; C lass WeekB lock; M odel Leaftostem=W eek; R andom B lock; Contrast 'linear' W eek 101; Contrast 'quadratic' W eek1 21; Run;

PAGE 148

148 ThefollowingSA Scodeswereusedtoanalyzecowandcalfbloodmetabolites (plasma ureanitrogen(PUN)andplasmaglucose(PUN) andcowBCS. D ata CowandCalfBloodMetabolitesandCowBCS ; I nput B lock P addock WeekTreatment $I nitialCalfPUN CalfPUN I nitialCalfPGlu C alf PG lu I nitialCowPUN CowPUN I nitialCowPGlu CowPGluInitialCowBCSCowBCS ; C ards; P roc M ixed D ata= CowandCalfBloodMetabolitesandCowBCS ; C lass BlockP addock WeekTreatment ; M odel CalfPUN C alf PG lu CowPUN CowPGluCowBCS = WeekTreatmentWeek*Treatment I n itialCalfPUN I nitialCalfPGlu I nitialCowPUN I nitialCowPGlu InitialCowBCS / S olution; R andom B lock Block*Treatment ; L smeans Week*Treatment / P diff; R un; Polynomialcontrasts for bloodmetabolites andcowBCSwereconductedforeach treatmentandtheSASco desarepresentedhere. D ata TrendsOverTimeCowandCalfBloodMetabolitesandCowBCS ; I nput B lock P addock WeekTreatment $I nitialCalfPUN CalfPUN I nitialCalfPGlu C alf PG lu I nitialCowPUN CowPUN I nitialCowPGlu CowPGluInitialCowBCSCowBCS ; C ards; P roc M ix ed D ata= TrendsOverTimeCowandCalfBloodMetabolitesandCowBCS ; C lass B lock Week ; M odel CalfPUN C alf PG lu CowPUN CowPGluCowBCS = Week I nitialCalfPUN I nitialCalfPGlu I nitialCowPUN I nitialCowPGlu InitialCowBCS / S olution; R andom B lock; C ontrast'line ar' W eek 0.7 1 00.7 1 ; C ontrast'quadratic' W eek0.4 1 0.8 2 0.4 1 ; R un; TheSAScodesusedtoanalyzecalfage,initialcalfBW,weaningweight,Beef ImprovementFederation(BIF)adjusted205 dweaningweights,calf83 d ADG ,andcow83 d ADGarepresente dhere. D ata CalfandCowPerformance ; I nput B lock PaddockTreatment$C alfsex $CalfageCowageCalfBirthWeightCalfInitialBW C alfF inalBWC alfADGBIF C owADG; C ards;

PAGE 149

149 P roc M ixed D ata= CalfandCowPerformance ; C lass B lock PaddockTreatment ; M odel C alfage= Treatment ; RandomBlock; L smeans Treatment / P diff; R un; P roc M ixed D ata= CalfandCowPerformance ; C lass B lock PaddockTreatment ; M odel C alfI nitial BW= TreatmentC alf BirthWeightCalfageC owage/ S olution; RandomBlock; L smeans Treatment / P diff; R un; P roc M ixed D ata= CalfandCowPerformance ; C lass B lock PaddockTreatment ; M odel C alfF inal BW= TreatmentC alfB irth W eight C alfI nitialBWCalfageC owage/ S olution; RandomBlock; L smeans Treatment / P diff; R un; P roc M ixed D ata= CalfandCowPerformance ; C la ss B lock PaddockTreatment ; M odelBIF= Treatmen t/ S olution; RandomBlock; L smeans Treatment / P diff; R un; P roc M ixed D ata= CalfandCowPerformance ; C lass B lock PaddockTreatment ; M odel C alfADG= TreatmentC alfB irth W eightC alfI nitialBWCalfageC owage/ S olution; RandomBlock; L smeans Treatment / P diff; R un; P roc M ixed D ata= CalfandCowPerformance ; C lass B lock PaddockTreatment ; M odel C owADG= TreatmentC alfB irth W eightC alfI nitialBWCalfageC owage/ S olution; RandomBlock; L smeans Treatment / P diff; R un; CalfBWthroughthegrazingperiodwasanalyzedwiththefollowingSAScodes: D ata CalfBodyWeight ; InputBlockPaddock Week Treatment$ C alfage CalfB irth W eight C owage Calf I nitial BWBW;

PAGE 150

150 C ards; P roc M ixed D ata= CalfBodyWeight ; C lass BlockP addock WeekTreatment ; M odelBW= TreatmentWeekTreatment*Week CalfageCalfBirthWeightCowage Calf I nitialBW / S olution; R andom B lock; L smeans Treatmen t* Week / P diff; R un; Polynomialcontrastsforcalf BWovertimewerecompletedbyenteringtreatmentsinto indi vidualSASfilesandusingtheSAScodespresentedhere. D ata ChangeofCalfBodyWeightOverTime ; InputBlockPaddock Week Treatment$ C alfage CalfB irth W eight C owage Calf I nitial BWBW; C ards; P roc M ixed D ata= ChangeofCalfBodyWeightOverTime ; C lass B lock PaddockWeek ; M odel BW=Week CalfageCalfBirthWeightCowageCalf I nitialBW / S olution; R andom B lock; Contrast 'linear' Week 0.67 0.220.220.67; Contrast 'quadratic' Week 0.5 0.50.5 0.5; Contrast 'cubic' Week 0 .220.67 0 .670.22; R un;

PAGE 151

151 APPENDIX I NETPRESENTVALUECA LCULATIONEXPLAINATI ONFOR T ABLE 8 2 Discountedcashflow=(income expense){1/(1+n)} y r W heren=7%interestrateandyr=0foryr1,1fory r2, .19fory r20 Expensesforyr1includedseedorbushelsofsprigs,fertil izer(330kg/ha0 20 40ratioof N:P 2 O 5 :K 2 O ),1,800kg/halime,herbicide,machinery,labor,andestimatedinterestonmonetary investment.Expensesforyr2includedseedforcowpea,pigeonpeaandsoybean,fertilizer(330 kg/ha0 20 40ratioof N:P 2 O 5 :K 2 O ),herbicide,machinery,labor,andestimatedintereston monetaryinvestment.Annualpeanutincludedseedcostevery5yr.Liming(1,800kg/ha)was includedinexpenses($80.00)inalternateyr. Incomewasestimatedbasedonthevalueofperennialpea nuthayat$37.00/140 kgbale. Netpresentvalue= for20yr

PAGE 152

152 LISTOFREFERENCES Abreu,A.,J.E.Carulla,C.E.Lascano,T.E.Daz,M.Kreuzer,andH.D.Hess.2004. Effectsof Sapindussaponaria fruitsonruminalfermentationandduodenalnitrogenflowofsheep fedatropicalgrassdietwithandwithoutalegume. J.A nim.Sci.82:1392 1400. Adams,N.R.1995.Detectionoftheeffectsofphytoestrogens on sheepandcattle. J.Anim.Sci. 73:1509 1515. Adesogan,A.T.,N.Krueger,M.B.Salawu,D.B.Dean,andC.R.Staples.2004.Theinfluenceof treatmentwithdualpurposeb acterialinoculantsorsolublecarbohydratesonthe fermentationandaerobicstabilityofbermudagrass.J.DairySci.87:3407 3416. Ahmed,M.M.,andH.S.Nour.1997.Legumehaysasasupplementfordairygoatsduringthedry season.SmallRumin.Res.26:1 89 192. Akin,D.E.,andD.Burdick.1975.Percentageoftissuetypesintropicalandtemperategrassleaf bladesanddegradationoftissuesbyrumenmicroorganisms.CropSci.15:661 668. Akinola,J.O.,andP.C.Whiteman.1974.Agronomicstudiesonpigeonp ea( Cajanuscajan (L.) Millsp.).II.Reponsestosowingdensity.Aust.J.Agric.Res.26:57 66. Albrecht,K.A.,andK.A.Beauchemin.2003.Alfalfaandotherperenniallegumesilages.Pages 633 664 in SilageScienceandTechnology.D.R.Buxton,R.E.Muck,a ndJ.H.Harrison, eds.Am.Soc.Agron.,CropSci.Soc.Am.,andSoilSci.Soc.Am.,Madison,WI. Alexander,G.,D.Ravi,Ch.RamakrishnaReddy,K.B.Saxena,J.Hanson,H.D.Upadhyaya, and M.Blmmel .2007. Forageyieldandqualityinpigeonpeagermplasmli nes.Semi Arid Tropicse J. www.icrisat.org/Journal/mpii/v3i1/chickpea_pigeonpea/Forage%20yield..%20(G%20Alex ander%20et%20al.).pdf AccessedJan.12,2008. Allen,V.G.,J.P.Fontenot,andR.A.Brock.2000.Foragesystemsforproductionofstocker steersintheuppersouth.J.Anim.Sci.78:1973 1982. Alonso Amelot,M.E.,A.Oliveros Bastidas a ,andM.P.Calcagno Pisarelli a .2007.Phen olics andcondensedtanninsofhighaltitude Pteridiumarachnoideum inrelationtosunlight exposure,elevation,andrainregime. Biochem.SystematicsEcol .35:1 10. ANKOM.2005a.Invit rotruedigestibilityusingtheDaisy II incubator. http://www.ankom.com/09_procedures/procedures6.shtml AccessedFeb.20,2006. ANKOM.2005b.Methodfordeterminingaciddetergentlignin inbeakers. http://www.ankom.com/09_procedures/procedures4b.shtml AccessedFeb.20,2006. AOAC.1990.Fiber(AcidDetergent)andLignininAnimalFeed.No.973.18inOfficial Methodso fAnalysis.15thed.Assoc.Off.Anal.Chem.,Arlington,VA.

PAGE 153

153 Arnold,G.W.1987.Grazingbehaviour.Pages129 136inManagedGrasslands:Analytical Studies(EcosystemsoftheWorld).R.W.Snaydon,ed.ElsevierSci.Publ.,Amsterdam. Asquith,T.N.andL.G.B utler.1985.Useofdye labeledproteinsasspectrophotometricassayfor proteinprecipitatessuchastannins.J.Chem.Ecol.11:1535 1544. Auldist,D.E.,K.L.Atkinson,M.J.Silvapulle,D.W.Dellow,andG.H.McDowell.1999. Utilisationofwhitecloversi lagefedaloneorwithmaizesilagebylactatingcows.Aust.J. Exp.Agric.39:237 246. Bagley,C.P.,R.L.White,R.L.Ivy,andR.C.Sloan.1997.Beefcow calfproductivityas influencedbyforage managementsystems.MississippiAgri.ForestryExp.Stn.Bu ll.No. 1065.VeronaandPrairie,MS. Balch,C.C.,andR.C.Campling.1962.Regulationofvoluntaryfoodintakeinruminants.Nutr. Abstr.Rev.32:669 686. Ball,D.M.,C.S.Hoveland,andG.D.Lacefield.2002.Pages1 322inSouthernForages.3rded. Grap hicCommunicationsCorporation,Lawrenceville,GA. Baloyi,J.J.,N.T.Ngongoni,J.H.Topps,T.Acamovic, andH.Hamudikuwanda.2001. Condensedtanninandsaponincontentof Vignaunguiculata (L.)Walp, Desmodium uncinatum Stylosanthesguianensis and Sty losanthesscabra growninZimbabwe. Trop. Anim.HealthandProd.33:57 66. Barahona,R.,C.E.Lascano,R.Cochran,J.Morrill,andE.C.Titgemeyer.1997.Intake, digestion,andnitrogenutilizationbysheepfedtropicallegumeswithcontrastingtannin conc entrationandastringency.J.Anim.Sci.75:1633 1640. Barnes,R.F.,andC.J.Nelson.2003.Foragesandgrasslandsinachangingworld.Pages17 18 inForages:AnIntroductiontoGrasslandAgriculture.6thed.R.F.Barnes,C.J.Nelson,M. Collins,andK. J.Moore,eds.IowaStateUniv.Press,Ames,IA. Bates,D.B.,W.E.Kunkle,C.G.Chambliss,andR.P.Cromwell.1989.Effectofdrymatterand additivesonbermudagrassandrhizomapeanutroundbalesilage.J.Prod.Agric.2:91 96. BeefImprovementFederati on.2006.GuidelinesforUniformBeefImprovement. http://www.beefimprovement.org/library/06guidelines.pdf AccessedOct.15,2007. Behling,A.2004.Tropicallegumeshowspromise.Page26inHayandForageGrower,Primedia Publication,Nov2004. Bennett s,H.W.,E.J.Underwood,andF.L.Skier.1946.Abreedingproblemofsheepinthe South WestdivisionofwesternAustralia.J.Agric.WestAus.23:1 12. Bergman,E.N.1990.Energycontributionsofvolatilefattyacidsfromthegastrointestinaltractin va riousspecies.Physiol.Rev.70:567 590.

PAGE 154

154 Bhardwaj,H.L.,M.Rangappa,andA.A.Hamama.1999.Chickpea,fababean,lupin,mungbean, andpigeonpea:potentialnewcropsfortheMid AtlanticRegionoftheUnitedStates.Page 202inPerspectivesonNewCropsan dNewUses.J.Janick,ed.ASHSPress,Alexandria, VA. Bishnoi,U.R.,andS.R.Mentreddy.2004.Comparativeinfluenceofnitrogenlevelsand intercroppedcowpeastandsonforageproductionofpearlmilletandsudan.CropRes. 27:162 168. Blount,A.R.,T.R. Sinclair,R.N.Gates,K.H.Quesenberry,andR.C.Littell.2001.Photoperiod responseinPensacolabahiagrass.Pages10 21inProc.29thIntl.Grassl.Congr., Piacicaba,SaoPaulo,Brazil. Blmmel,M.,S.Vellaikumar,R.Devulapalli,S.N.Nigam,H.D.Upa dhyaya, andA.Khan. 2005.Preliminaryobservationsonlivestockproductivityinsheepfedexclusivelyon haulmsfromelevencultivarsofgroundnut.SATeJournal. www. ejournal.icrisat.org AccessedMar.1,200 8. Bochers,R.1977.Allantoindetermination.Anal.Biochem.79:612 613. Bowman,J.G.P.,C.W.Hunt,M.S.Kerley,andJ.A.Paterson.1991.Effectsofgrassmaturityand legumesubstitutiononlargeparticlesizereductionandsmallparticleflowfromtheru men ofcattle.J.Anim.Sci.69:369 378. Brake,A.C.,A.L.Goetsch,L.A.Forster,Jr.,andK.M.Landis.1989.Feedintake,digestionand digestacharacteristicsofcattlefedbermudagrassororchardgrassaloneorwithground barleyorcorn.J.Anim.Sci.6 7:3425 3436. Bransby,D.I.,A.G.Matches,andG.F.Krause.1977.Diskmeterforrapidestimationofherbage yieldingrazingtrials.Agron.J.69:393 396. Brink,G.E.,andT.E.Fairbrother.1988.Cool andwarm seasonforagelegumepotentialforthe southe asternUSA.Trop.Grassl.22:116 125. Broderick,G.A.1995.Desirablecharacteristicsofforagelegumesforimprovingprotein utilizationinruminants.J.Anim.Sci.73:2760 2773. Broderick,G.A.,andK.A.Albrecht.1997.Ruminalinvitrodegradationofp roteinintannin free andtannin containingforagelegumespecies.CropSci.37:1884 1891. Bulo,D.,G.J.Blair,W.St r,andA.R.Till.1994.Yieldanddigestibilityofforagesineast Indonesia:I.Legumes.Aust.J.Anim.Sci.7:325 333. Butler,N.L.,J. M.Dawson,D.Wakelin,andP.J.Buttery.2000.Effectofdietarytanninand proteinconcentrationonnematodeinfection( Trichostrongyluscolubriformis )inlambs.J. Agric.Sci.134:89 99.

PAGE 155

155 Byers,F.M.,andA.L.Moxon.1980.Proteinandseleniumlevelsfo rgrowingandfinishingbeef cattle.J.Anim.Sci.50:1136 1144. Canale,A.,M.E.Valente,andA.Ciotti.1984.Determinationofvolatilecarboxylicacids(C1 C5)andlacticacidinaqueousacidextractsofsilagebyhigh performanceliquid chromatography. J.Sci.FoodAgric.35:1178 1182. Carulla,J.,C.Lascano,andT.Klopfenstein.2001.Reductionoftanninlevelinatropicallegume ( Desmodiumovalifolium )withpolyethyleneglycol(PEG):EffectsonintakeandN balance,digestionandabsorptionbysheep .Arch.Latinoam.Prod.Anim.9:17 24. CarvalhoMoretzsohn,M.M.S.Hopkins,S.E.Mitchell,S.Kresovich,J.Francisco,M.Valls, and M.E.Ferreira.2004. Geneticdiversityofpeanut( Arachishypogaea L.)anditswild relativesbasedontheanalysisofhyp ervariableregionsofthegenome. BMCPlantBio. 4:11 20. Chambliss,C.G.2002. Bahiagrass.Univ.ofFlorida,Agron.Depart.,Instit.ofFoodandAgric. Sci.Publ.No.SS AGR 36.Gainesville,FL. Chandler,J.A.,W.J.Jewell,J.M.Gossett,P.J.VanSoest,a ndJ.B.Robertson.1980.Predicting methanefermentationbiodegradability.Biotechnol.Bioeng.10:93 107. Chen,X.B.,Y.K.Chen,M.F.Franklin,E.R.rskov,andW.J.Shand.1992.Theeffectoffeed intakeandbodyweightonpurinederivativeexcretionand microbialproteinsupplyin sheep.J.Anim.Sci.70:1534 1542. Cheong,Y.K.,Choi,Y.H.Park,K.H.,Oh,Y.S.,Kim,W.H.,Park,M.S.,andKim,S.C. 2002. Effectofharvestingtimeandadditivesonthenutritivevalueofpeanutsilages.KoreanJ. CropSci. 47:147 150. Chintapalli,P.L.,J. P. Moss,K.K. Sharma,andJ. K. Bhalla.1997. Invitrocultureprovides additionalvariationforpigeonpea.InVitroCell.andDev.Bio. Plant.33:30 37. Clark,J.H.,T.H.Klusmeyer,andM.R.Cameron.1992.Microbialpr oteinsynthesisandflows of nitrogenfractionstotheduodenumofdairycows. J. Dairy Sci.75:2304 2323. Coffey,K.P,G.V.Granade,andJ.L.Moyer.1995.Nutrientcontentofsilagesmadefrom whole plantsoybeans.Prof.Anim.Sci.11:74 80. Coleman,S .W.,andJ.E.Moore 2003.Feedqualityandanimalperformance. FieldCropsRes. 84:17 29. Collins,M.,andD.B.Hannaway.2003.Pages415 441inForages:AnIntroductiontoGrassland Agriculture.6t hed.R.F.Barnes,C.J.Nelson,M.Collins,K.J.Moore,eds.IowaState Univ.Press,Ames,IA. Contreras Govea,F.E.,K.A.Albrecht,andR.E.Muck.2006. Springyieldandsilage characteristicsofkuraclover,winterwheat,andinmixtures. Agron.J.98:78 1 787.

PAGE 156

156 Corriher,V.A.,G.M.Hill,J.G.Andrae,M.A.Froetschel,andB.G.Mullinix,Jr.2007.Cowand calfperformanceonCoastalorTifton85bermudagrasspastureswithaeschynomene creep grazingpaddocks.J.Anim.Sci.85:2762 2771. Coulombe,J.J.,andL .Favreau.1963.Anewsimplesemimicromethodforcolorimetric determinationofurea.Clin.Chem.9:102 108. Dean,D.B.,A.T.Adesogan, N.Krueger, andR.C.Littell .2005. Effectoffibrolyticenzymeson thefermentationcharacteristics,aerobicstabilit y,anddigestibilityofbermudagrasssilage. J.DairySci.88:994 1003. Dewhurst,R.J.,D.R.Davies,andR.J.Merry.2000.Microbialproteinsupplyfromtherumen. Anim.FeedSci.Technol.85:1 21. Dewhurst,R.J.,R.T.Evans,N.D.Scollan,J.M.Moorby, R.J.Merry,andR.J.Wilkins.2003a. Comparisonofgrassandlegumesilagesformilkproduction.2.Invivoandinsacco evaluationsofrumenfunction.J.DairySci.86:2612 2621. Dewhurst,R.J.,W.J.Fisher,J.K.S.Tweed,andR.J.Wilkins.2003b.Comparis onofgrassand legumesilagesformilkproduction.1.Productionresponseswithdifferentlevelsof concentrate.J.DairySci.86:2598 2611. Diggs,Jr.,G.M.,B.L.Lipscomb,andR.J.OKennon.1999.Page662inShinnersandMahlers IllustratedFloraofN orthCentralTexas.BotanicalRes.Inst.TexasandAustinCollege, FortWorth,TX. Dobson,D.E.,E. M. Prager,andA.C.Wilsong.1984.Stomachlysozymesofruminants.I. Distributionandcatalylicproperties.J.Biol.Chem.259:11607 11616. Dove,H.,andJ. A.Milne.1994.Digestaflowandrumenmicrobialproteinproductioninewes grazingperennialryegrass.Aust.J.Agric.Res.45:1229 1245. Duble,R.L.,J.A.Lancaster,andE.C.Holt.1971.Foragecharacteristicslimitinganimal performanceonwarm seasonp erennialgrasses.Agron.J.63:795 798. Elizalde,J.C.,J.D.Cremin,Jr.,D.B.Faulkner,andN.R.Merchen.1998. Performanceand digestionbysteersgrazingtallfescueandsupplementedwithenergyandprotein. J.Anim. Sci.76:1691 1701. Ellis,W.C.,M.M ahlooji,C.E.Lascano,andJ.H.Matis.2005.Effectsofsizeofingestively masticatedfragmentsofplanttissuesonkineticsofdigestionofNDF.J.Anim.Sci. 83:1602 1615. Ene Obong,H.N.1995.Contentofanti nutrientsandinvitroproteindigestibil ityoftheAfrican yambean,pigeonpea,andcowpea.PlantFoodsforHumanNutr.48:225 233.

PAGE 157

157 Erlinger,L.L., D. R. Tolleson,and C. J.Brown.1990. Comparisonofbitesize,bitingrateand grazingtimeofbeefheifersfromherdsdistinguishedbymaturesize andrateofmaturity. J.Anim. Sci.68:3578 3587. Evans,J.R.1989.PhotosynthesisandnitrogenrelationshipinleavesofC 3 plants.Oecologia. 78: 9 19. Faris,D.G.,andU.Singh.1990.Pages401 433inThePigeonpea.Y.L.Nene,S.D.Hall,and V.K.Sheila ,eds.CABIntl.:Intl.CropsRes.Inst.fortheSemi AridTropics,Cambridge Univ.Press,Cambridge,UK. FASS.2007.FloridaAgriculturalStatisticalDirectory. www.florida agriculture.com/pubs/pubform/pdf/Florida_Agricultural_Statistical_Directory.pdf AccessedMar.22,2008. FAWN,2008.FloridaAutomatedWeatherNetwork,Marianna,FL.ArchivedWeatherDatabase. http://fawn.ifas.ufl.edu/data/ AccessedJanuary30,2008. FCC,2008.FloridaClimateCenter.Marianna,FL.NormalsandAveragesfor1961to1990. http://www.sercc.com/cg i bin/sercc/cliMAIN.pl?fl5372 AccessedJan.30,2008. Fehr,W.R.,C.E.Caviness,D.T.Burmood,andJ.S.Pennington.1971.Stageofdevelopment descriptionsforsoybeans, Glycinemax (L.)Merrill.CropSci.11:929 931. Field,C.,andH.A.Mooney.1986.The photosynthesis nitrogenrelationshipinwildplants. Pages22 25inOntheEconomyofPlantFormandFunction.T.AGivinish,ed.Cambridge UniversityPress,London. Flores,J.A.2008.Perennialpeanutforqualitypasturageandhay.Agric.Res.53:16 17. F lores,J.A.,J.E.Moore,andL.E.Sollenberger.1993.Determinantsofforagequalityin PensacolabahiagrassandMottelephantgrass.J.Anim.Sci.71:1606 1614. Forbes,T.D.A.,andJ.Hodgson.1985.Comparativestudiesoftheinfluenceofsward condition sontheingestivebehaviourofcowsandsheep.GrassandForageSci.40:69 77. Foster,J.L.,J.P.Muir,B.D.Lambert,andD.Pawelek.2007. Insituandinvitrodegradationof nativeTexaswarm seasonlegumesandalfalfaingoatsandsteersfedasorghum sudan basaldiet.Anim.FeedSci.Technol.133:228 239. Frame,J.2005.ForageLegumesforTemperateGrasslands.FoodandAgric.Org.United Nations.SciencePublishers,Inc.Enfield,NH. Francia,U. ,S. Terramoccia,andF. Martillotti. 19 93.P roductiveandnutritivecharacteristicsof thespeciesof Cajanuscajan asforageandgrain.REURTechnicalSeries FAORegional OfficeforEurope.28:44 46.

PAGE 158

158 Franssen,H.J.,I.Vijn,W.C.Yang,andT. Bisseling.1992.Developmentalaspectsofthe Rhizobium legumesymbiosis.Plt.Molec.Biol.19:89 107. French,E.C.,G.M.Prine,andA.R.Blount.2006.Perennialpeanut:analternativeforageof growingimportance.Univ.ofFLAgron.Dept.,FLCooper ativeExtensionService,Inst. FoodandAgric.Sci.Publ.No.SS AGR 39. http://edis.ifas.ufl.edu/AA148 AccessedMar. 3, 2007. Fujihara,T.,E.R.rskov,P.J.Reed,andD.J.Kyle.1987.Theeffectofprotein infusionon urinaryexcretionofpurinederivativesinruminantsnourishedbyintragastricinfusion.J. Agric.Sci.109:7 12. Funderburg,E.2005.Stretchyourinputdollars.AgNewsandViews. http://www.noble.org/Ag/Soils/InputDollars/index.html AccessedJan.12,2006. Funston,R.N.2004. Fatsupplementationandreproductioninbeeffemales. J.Anim.Sci.82(E. Suppl.):E154 E161. Gallaher,R.N.,C.O.Weldon,andJ.G.Futral.1975.A naluminumblockdigesterforplantand soilanalysis.SoilSci.Soc.Am.Proc.39:803 806. Gates,R.N.,C.L.Quarin,andC.G.S.Pedreira.2004.Bahiagrass.Pages651 680inWarm Season(C 4 )Grasses.Am.Soc.OfAgron.,CropSci.Soc.ofAm.,SoilSci. Soc.ofAm. Madison,WI. Gates,R.N.,G.M.Hill,andG.W.Burton.1999. Responseofselectedandunselectedbahiagrass populationstodefoliation.Agron.J.91:787 797. Gates,R.N.,P.Mislevy,andF.G.Martin.2001.Herbageaccumulationofthreebahiagra ss populationsduringthecoolseason.Agron.J.93:112 117. GetachewG.,A.N.Said,andF.Sundstol.1994.Theeffectofforagelegumesupplementationon digestibilityandbodyweightgainbysheepfedabasaldietofmaizestover.Anim.Feed Sci.Technol .46:97 108. Gochman,N.,andJ.M.Schmidz.1972.Applicationofanewperoxideindicatorreactiontothe specific,automateddeterminationofglucosewithglucoseoxidase.Clin.Chem.18:943 952. Goetsch,A.L.,A.R.Patil,Z.S.Wang,K.K.Park,D.L.Gallo way,Sr.,J.E.Rossi,andB. Kouakou.1997.Netfluxofnutrientsacrosssplanchnictissuesinwethersconsuminggrass haywithorwithoutcornandalfalfa.Anim.FeedSci.Technol.66:271 282. Gorbet,D.W.,andF.M.Shokes.2002. Registrationof Florida MDR 98 Peanut CropSci.42:2207a 2208a. Gordon,A.J.,J.D. Hesketh,andD.B. Peters.1982.Soybeanleafphotosynthesisinrelationto maturityclassificationandstageofgrowth.PhotosynthesisRes.3:81 93.

PAGE 159

159 Grichar,W.J.,D.C.Sestak,A.J.Jaks,G.R.Sm ith,andG.W.Evers.1995.Warm seasonlegume evaluationsonalkalinesoils.TexasAgri.Exp.Stn.Overton,TX. Haddad,S.G.,2000.Associativeeffectsofsupplementingbarleystrawdietswithalfalfahayon rumenenvironmentandnutrientintakeanddi gestibilityforewes.Anim.FoodSci. Technol.87:163 171. Hagerman,A.E.1994.Purificationofquebrachotannin. http:// www.users.muohio.edu/hagermae/tannin.pdf AccessedFeb.2006. Hall,M.B. ,andC.Herejk.2001.Differencesinyieldsofmicrobialcrudeproteinfrominvitro fermentationofcarbohydrates.J.DairySci.84:2486 2493. Hammond,A.C.,M.J.Williams,T.A.Olson,L.C.Gasbarre,E.A.Leighton,andM.A. Menchaca.1997.Effectofrot ationalvscontinuousintensivestockingofbahiagrasson performanceofAnguscowsandcalvesandinteractionwithsiretypeongastrointestinal nematodeburden.J.Anim.Sci.75:2291 2299. Harrelson,L.L.,A.C.Hammond,M.J.Williams,andW.E.Kunkle.19 94.Dietselectionbysteers grazingrhizomapeanut( Arachisglabrata ) tropicalgrasspastures.J.Anim.Sci.72(Suppl. 2):29.(Abstr.) Harrison,D.G.,D.E.Beever,D.J.Thomson,and D. F.Osbourn.1976.Manipulationof fermentationintherumen.J.Sci.Fo odAgric.27:617 620. Harrison,D.G., D. E.Beever,D.J..Thomson.andD. F. Osbourn.1975.Manipulationofrumen fermentationinsheepbyincreasingtherateofflowofwaterfromtherumen.J.Agric. Sci. 85:93 101. Hatch,M.D.,andC.R.Slack.1966.Photos ynthesisbysugarcaneleaves.Anewcarboxylation reactionandthepathwayofsugarformation.Biochem.J.101:103 111. Heinrichs,J.,andV.Ishler.2000.Evaluatingforagequalitybyvisualappraisal,pH,anddry mattercontent.PennsylvaniaStateUniv. Dept.ofDairyandAnim.Sci.and Cooperative Extension. http://www.das.psu.edu/dairynutrition/documents/evalfor.pdf AccessedDec. 14, 2007. HernndezGaray,A.,L.E.Sollenberger ,C.R.Staples,andC.G.Pedreira.2004.Florigrazeand ArbrookrhizomapeanutaspastureforgrowingHolsteinheifers.CropSci.44:1355 1360. Hewitt,T.2006.Enterprisebudgets. http://nfr ec.ifas.ufl.edu/Hewitt/budgets.htm AccessedApr. 8, 2008. Higuera,A.R.N.Gallaher,andG.E.MacDonald.2001.Responseofcowpea( Vigna unguiculata )totillageandherbicidemanagement.Proc.SouthernConservationAgric. Sys.Conf.,OklahomaCity,OK.

PAGE 160

160Hobbs,N.T.1999.Responsesoflargeherbivorestospatialheterogeneityinecosystems.Page106inNutritionalEcologyofHerbivores.H.G.JungandG.C.Fahey,eds.Proc.5thIntl.Symp.Nutr.Herbivores.Savory,IL.Am.Soc.Anim.Sci.Hopkins,C.G.1896.Compositionanddigestibilityofcornensilage,cowpeaensilage,sojabeanensilage,andcorn-fodder.Univ.ofIllinoisAg.Exp.Station.Bull.No.43.http://www.ideals.uiuc.edu/bitstream/2142/3116/1/compositiondiges00hopk.pdfAccessedJan.17,2008.Hoskins,S.O.,P.R.Wilson,T.N.Barry,W.A.G.Charleston,andG.C.Waghorn.2000.Effectofforagelegumescontainingcondensedtanninsonlungworm(Dictyocaulussp.)andgastrointestinalparasitisminyoungreddeer(Cervuselaphus).Res.Vet.Sci.68:223-230.Hourou,Le.2006.Cajanuscajan(L.)Millsp.FAO.http://www.fao.org/AG/aGp/agpc/doc/GBASE/DATA/PF000150.HTM AccessedJan.12,2006.Jackson,F.S.,W.C.McNabb,T.N.Barry,Y.L.Foo,andJ.S.Peters.1996.Thecondensedtannincontentofarangeofsubtropicalandtemperateforagesandthereactivityofcondensedtanninwithribulose-1,5-bis-phosphatecarboxylase(Rubisco)protein.J.Sci.FoodAgric.72:483-492.Johnson,C.R.,B.A.Reiling,P.Mislevy,andM.B.Hall.2001.Effectsofnitrogenfertilizationandharvestdateonyield,digestibility,fiber,andproteinfractionsoftropicalgrasses.J.Anim.Sci.79:2439-2448.Johnson,Jr.,J.C.,J.L.Butler,andE.J.Williams.1979.Compositionandnutritivevalueofwholeplantpeanuts(ArachishypogaeaL.)ensiledwithandwithoutpropionicacid-formaldehydetreatment.J.DairySci.62:1258-1263.Jones,J.D.,B.J.Gossett,J.R.Harris,andJ.E.Toler.1989.Cowpea(Vignaunguiculata)controlinsoybean(Glycinemax)withActifluorfen,Clorimuron,andThismeturon.WeedTechnol.3:518-522.Jones,R.M.2001.Evaluationoflegumesandgrassesincoastalsouth-eastQueensland.Trop.Grassl.35:85-95.Jung,H.G.,andM.S.Allen.1995.Characteristicsofplantcellwallsaffectingintakeanddigestibilityofforagesbyruminants.J.Anim.Sci.73:2774-2790.Kalmbacher,R.S.,andA.Kretschmer.2002.Pintoiperennialpeanut.TheFloridaCattlemanandLivestockJ.,Feb.2002:13-14.Karachi,M.,andM.Zengo.1998.Legumeforagesfrompigeonpea,leucaenaandsesbaniaassupplementstonaturalpasturesforgoatproductioninwesternTanzania.AgroforestrySyst.39:13-21..DUFKHV\--DQG5:+HPLQJZD\&RQGHQVHGWDQQLQV::O:f-linkedprocyanidinsinArachishypogaeaL.J.Agric.FoodChem.34:966-970.

PAGE 161

161 Karungi,J.,E.Adipala,P.Nampala,M.W. Ogenga LatigoandS.Kyamanywa.2000.Pest managementincowpea.Part3.Quantifyingtheeffectofcowpeafieldpestsongrainyields ineasternUganda.CropProt.19:343 347. Kelly,K.E.,andB.R.Sinclair.1989.Sizeandstructureofleafandstalkcompo nentsofdigesta regurgitatedforruminationinsheepofferedfiveforagediets.NewZealandJ.ofAgric. Res.32:365 374. Kenako,J.J.1989.Clinicalbiochemistryofdomesticanimals.AcademicPress,NY,pp.886 891. Kiesling,D.O.,andH.A.Swartz.1997. Growthandcarcasscharacteristicsoflambsgrazing cowpea,sudangrassorfedindrylot.SmallRumin.Res.26:171 175. Kostenbauder,M.J.,S.W.Coleman, C.C.ChaseJr.,W.E.Kunkle, M.B.Hall,andF.G.Martin. 2007. I ntakeanddigestibilityofbahiagras shaybycattlethataresupplementedwith molassesormolasses ureawithorwithoutsoybeanhulls. Prof.Anim.Sci.23:373 380. Kster,H.H.,R.C.Cochran,E.C.Titgemeyer,E.S.Vanzant,I.Abdelgadir,andG.St Jean.1996. Effectofincreasingdegradable intakeproteinonintakeanddigestionoflow quality, tallgrass prairieforagebybeefcows. J.Anim.Sci.74:2473 2481. Ku,S.B.,andG.E.Edwards.1978.Oxygeninhibitionofphotosynthesis.III.Temperature dependenceofquantumyieldanditsrelation toO 2 /CO 2 solubilityratio.Planta.140:1 6. Lagasse,M.P.,A.L.Goetsch,K.M.Landis,andL.A.Forester.1990.Effectsofsupplemental alfalfahayonfeedintakeanddigestionbyHolsteinsteersconsuminghigh quality bermudagrassororchardgrasshay.J. Anim.Sci.68:2839 2847. Lambert,M.R.,N.L.Jacobson,R.S.Allen,andM.R.Bell.1955.Therelationofgrowth,feed consumptionandcertainbloodconstituentstochangesinthedietofyoungdairycalves.J. DairySci.38:6 16. Larcher,W.2003.Physiolog icalPlantEcology:EcophysiologyandStressPhysiologyof FunctionalGroups.Fourthed.Springer,NewYork,NY. Lee,M.R.F.,L.J.Harris,R.J.Dewhurst,R.J.Merry,andN.D.Scollan.2003a.Theeffectof cloversilagesonlongchainfattyacidrumentrans formationsanddigestioninbeefsteers. J.Anim.Sci.76:491 501. Lee,M.R.F.,R.J.Merry,D.R.Davies,J.MMoorby,M.O.Humphreys,M.K.Theodorou,J.C. MacRae,andN.D.Scollan.2003b.Productionresponsesfromlambsgrazedon Lolium perenne selectedfor anelevatedwater solublecarbohydrateconcentration.Anim.Res. 50:59 70. Leep,R.,P.Jeranyama,D.H.Min,T.Dietz,S.Bughrara,andJ.Isleib.2002.Grazingeffectson herbagemassandcompostitioningrass birdsfoottrefoilmixtures.Agron.J.94:12 57 1262.

PAGE 162

162 Loy,T.W.,G.P.Lardy,M.L.Bauer,W.D.Slanger,andJ.S.Caton.2002.Effectsof supplementationonintakeandgrowthofnursingcalvesgrazingnativerangein southeasternNorthDakota.J.Anim.Sci.80:539 543. Marshall,D.M.1994.Breeddiffer encesandgeneticparametersforbodycompositiontraitsin beefcattle.J.ofAnim.Sci.72:2745 2755. Mary,S.S.,andA.Gopalan.2006.Dissectionofgeneticattributesamongyieldtraitsoffodder cowpeainF 3 andF 4. J.AppliedSci.Res.2:805 808. Ma sama,E.,J.H.Topps,N.T.Ngongoni,andB.V.Maasdorp.1997.Effectsofsupplementation withfoliagefromthetreelegumes Acaciaangustissima Cajanuscajan Calliandra calothyrsus and Leucaenaleucephala onfeedintake,digestibilityandnitrogenmetabo lism ofsheepgivenmaizestoveradlibitum.Anim.FeedSci.Technol.69:233 240. MatizhaW., N.T.Ngongoni,andJ.H. Topps.1997.Effectofsupplementingveldhaywith tropicallegumes Desmodiumuncinatum Stylosanthesguianensis and Macroptilium atropur pureum onintake,digestibility,outflowrates,nitrogenretentionandliveweight gaininlambs. Anim.FeedSci.an dTechnol. 69:187 193. McAllister,T.A.,R.Feniuk,Z.Mir,P.Mir,L.B.Selinger,andK.J.Cheng.1998.Inoculantsfor alfalfasilage:effectsonaerobicstability,digestibilityandthegrowthperformanceof feedlotsteers.Livest.Prod.Sci.53:171 18 1. McCarthy,R.D.,andE.M.Kesler.1956.Relationshipbetweenageofcalf,bloodglucose,blood andrumenlevelsofvolatilefattyacids,andinvitrocellulosedigestion.J.DairySci.39: 1280. McCullough,I.E., L. R.Sisk,O.E.Sell,A.R.Stasc,andD. L.Cason. 1960.Influenceof preservativesonthefermentation,nutrientrecovery,andfeedingvalueofalfalfa,starr millet,andcowpeaandsudangrasssilages.J.DairySci.43:1826 1832 McDonald,P.,N.Henderson,andS.Heron.1991.TheBiochemistryo fSilage.2nded. ChalcombePublications,Marlow,UK. McKersie,B.D.1983.EffectofpHonproteolysisinensiledlegumeforage.Agron.J.77:81. McMahon,L.R.,T.A.McAllister,B.P.Berg,W.Majak,S.N.Acharya,J.D.Popp,B.E. Coulman,Y.Wang,andK. J. Cheng.2000.Areviewoftheeffectsofforagecondensed tanninsonruminalfermentationandbloatingrazingcattle.CanadianJ.ofPlantSci. 80:469 485. Meissner,H.H.,andD.V.Paulsmeier.1995.Plantcompositionalconstituentsaffectingbetween plan tandanimalspeciespredictionofforageintake.J.Anim.Sci.73:2447 2457.

PAGE 163

163Merry,R.J.,M.R.F.Lee,D.R.Davies,R.J.Dewhurst,J.M.Moorby,N.D.Scollan,andM.K.Theodorou.2006.Effectsofhigh-sugarryegrasssilageandmixtureswithredcloversilageonruminantdigestion.1.Invitroandinvivostudiesofnitrogenutilization.J.Anim.Sci.84:3049-3060.Min,B.R.,T.N.Barry,G.T.Attwood,andW.C.McNabb.2003.Theeffectofcondensedtanninsonthenutritionandhealthofruminantsfedfreshtemperateforages:Areview.Anim.FeedSci.Technol.106:3–19.Min,B.R.,Attwood,G.T.,McNabb,W.C.,Molan,A.L.,andBarry,T.N.2005.TheeffectofcondensedtanninsfromLotuscorniculatusontheproteolyticactivitiesandgrowthofrumenbacteria.Anim.FeedSci.Technol.121:45–58.Minson,D.J.,andR.Milford.1967.Thevoluntaryintakeanddigestibilityofdietscontainingdifferentproportionsoflegumeandmaturepangolagrass(Digitariadecumbens).Aust.J.Exp.Agric.Anim.Husb.7:546-551.Minson,D.J.,T.Cowan,andE.Havilah.1993.Northerndairyfeedbase2001.1.Summerpastureandcrops.Trop.Grassl.27:131-149.Mir,P.S.,andZ.Mir.1993.Growthofanddigestibilitybysheepfeddietscomprisingmixturesofgrassandlegumehaycomparedwiththosefedhigh-graindiets.Can.J.Anim.Sci.73:101-107.Mislevy,P.,A.R.Blount,F.G.Martin,andB.T.Scully.2005.Soybeanandclaycowpeagrownforforageproductioninthesubtropics.CropManagement.doi:10.1095/CM-2005-0926-01-RS.http://www.plantmangementnetwork.org/pub/cm/research/2005/forage/AccessedOct.3,2006.Moore,J.E.,Kunkle,W.E.,andBrown,W.F.1991.Foragequalityandtheneedforproteinandenergysupplements.Pages113-123inProc.BeefCattleShortCourse,Dept.Anim.Sci.,Univ.ofFlorida,Gainesville.Morrison,F.B.1956.Feedsandfeeding.Twenty-seconded.TheMorrisonPubl.Co.,Ithaca,NY.Moseley,G.1981.Theroleofphysicalbreakdownincontrollingthenutritivequalityofforages.Pages167-182inWelshPlantBreedingStn.Ann.Rep.Aberystwyth,Wales.Mosi,A.K.,andM.H.Butterworth.1985.Thevoluntaryintakeanddigestibilityofcombinationsofcerealcropresiduesandlegumehayforsheep.Anim.FeedSci.andTechnol.12:241-251.Muchow,R.C.1985.Canopydevelopmentofgrainlegumesgrownunderdifferentsoilandwaterregimesinasemi-aridtropicalenvironment.FieldCropRes.11:99-109.Muck,R.E.1988.Factorsinfluencingsilagequalityandtheirimplicationsformanagement.J.DairySci.71:2992-3002.

PAGE 164

164 Muir,J.P.2002.Hand pluckedforageyieldandqualityandseedproductionfromannualand short lived perennialwarm seasonlegumesfertilizedwithcompostedmanure.CropSci. 42:897 904. Muir,J.P.,S.R.Stokes,andE.P.Prostko.2001.Theeffectofdairycompostonsummerannual dicotsgrownasalternativesilages.Prof.Anim.Sci.17:95 100. Muldoon ,D.K.1985.Summerforagesunderirrigation:4.Thegrowthandmineralcomposition offoragelegumes.Aust.J.Exp.Agric.25:417 423. Mupwanga,J.F.,N.T.Ngnongoni,J.H.Hopps,andH.Hamudikuwanda.2000a.Effectsof supplementingabasaldietof Chlori sgayana haywithoneofthreeprotein richlegume haysof Cassiarotundifolia Lablabpurpureus and Macroptiliumatropurpureum forageon somenutritionalparametersingoats.Trop.Anim.HealthProd.32:245 256. Mupwanga,J.F.,N.T.Ngnongni,J.H.Hopps, T.Acamovic,H.Hamudikuwanda,andL.R. Ndlovu.2000b.Drymatterintake,apparentdigestibilityandexcretionofpurine derivativesinsheepfedtropicallegumehay.SmallRumin.Res.36:261 268. NASS.2002.CensusofAgriculture:FloridaStateLevelDat a. http://www.nass.usda.gov/census/census02/volume1/fl/index1.htm AccessedApr.7, 2008. NASS.2007.CropProductionAnnualSummary. http://usda.mannlib.cornell.edu/MannUsda/viewDocumentInfo.do?documentID=1047 AccessedMar.1,2008. NASS.2006.FloridaStateAgricultureOverview. http://www.nass.usda.gov/Statistics_by_State/Ag_Overview/AgOverview_FL.pdf AccessedMar.17,2008. NDA.1997.CultivatingCowpeas.Natl.DepartmentofAgric.,NorthWestAgric.Dev.Inst.Info ParkResourceCentre.Republi cofSouthAfrica.Cowpeas1/1997. Ndlovu,L.R.,andJ.G.Buchanan Smith.1985.Utilisationofpoorqualityroughagebysheep. Effectofalfalfasupplementationofruminalparameters,fibredigestionandrateofpassage fromtherumen.Can.J.Anim.Sci. 65:693 703. Nene,Y.L.,andV.K.Sheila.1990.Pigeonpea:geographyandimportance.Pages1 14inThe Pigeonpea.Y.L.Nene,S.D.Hall,andV.K.Sheila,eds.CABIntl.:Intl.CropsRes.Inst. fortheSemi AridTropics,Univ.Press,Cambridge,UK. Neville ,W.E.,Jr.1962.Influenceofdamsmilkproductionandotherfactorson120and240 dayweightofHerefordcalves.J.Anim.Sci.21:315. Nevins,D.J.1993.Analysisofforagecellwallpolysaccharides.p105 129.In:Foragecellwall structureanddigesti bility.H.G.Jung,D.R.Buxton,R.D.HatfieldandJ.Ralph(Eds.). ASA,CSSA,SSSA,Madison,WI.

PAGE 165

165 Newman,Y.C.,andC.G.Chambliss.2003.Warm season(summer)foragelegumeguide.Univ. ofFlorida,Agron.Dept.,Inst.FoodAgric.Sci.Circ.SS AGR 48.Un iv.ofFlorida, Gainesville. Noel,R.J.,andL.G.Hambleton.1976.Collaborativestudyofasemiautomatedmethodfor determinationofcrudeproteininanimalfeeds.J.Assoc.Off.Anal.Chem59:134 140. NoualaF.S.,O.O.Akinbamijo,O.B.Smith,andV. S.Pandey.Horticulturalresiduesasruminant feedinperi urbanareaofTheGambia.2004. LivestockResearchforRuralDevelopment, Vol.16,Art.#37. http://www.cipav.org.co/lrrd/lrrd16/ 6/noua16037.htm AccessedMar.9, 2008. NRC.2000.NutrientRequirementsofBeefCattle.7threv.ed.Natl.Acad.Press,Washington, DC. Occumpaugh,W.R.,andG.A.Dusi.1981.Creepgrazingforcalvesusingwarm seasonlegumes. ForageGrassl.Prog.22:3 4 rskov,E.R.1992.ProteinNutritioninRuminants.Seconded.AcademicPress,Inc.SanDiego, CA. Ortega S.,J.A.,L.E.Sollenberger,K.H.Quesenberry,J.A.Cornell,andC.S.Jones.1992. Productivityandpersistenceofrhizomapeanutpasturesunderdif ferentgrazing management.Agron.J.84:799 804. Otero,J.R.1952.Informaessobrealgumasplantasforrageiras.ServiodeInformao Agrcola.11:1 313. Owens,F.N.,andA.L.Goetsch.1986.Digestapassageandmicrobialproteinsynthesis.Page196 inCo ntrolofDigestionandMetabolisminRuminants.L.P.Milligan,W.L.Grovum,and A.Dobson,eds.Prentice Hall,EnglewoodCliffs,NJ. Owens,F.N.,andA.L.Goetsch.1988.Ruminalfermentation.Pages145 171inTheRuminant Animal:DigestivePhysiologyan dNutrition.D.C.Church,ed.Prentice Hall,Englewood Cliffs,NJ. Owens,V.N.,K.A.Albrecht,R.E.Muck,andS.H.Duke.1999. Proteindegradationand fermentationcharacteristicsofredcloverandalfalfasilageharvestedwithvaryinglevelsof totalnon structuralcarbohydrates.CropSci.39:1873 1880. Packard,C.E.2004.Peanutstoverandbermudagrasshayforwethersonsummerhardwood rangeinnorthcentralTexas.M.S.Thesis,TarletonStateUniv.,Stephenville,TX. Pengelly,B.C.,andM.J.Conway.20 00.Pasturesoncroppingsoils:whichtropicalpasture legumetouse?Trop.Grassl.34:162 168. Petit,H.V.,andG.F.Tremblay.1992.Insitudegradabilityoffreshgrassandgrassconserved underdifferentharvestingmethods.J.DairySci.75:774 781.

PAGE 166

166 Pha tak,S.C.,R.G.Nadimpalli,S.C.Tiwari,andH.L.Bhardwaj.1993.Pigeonpeas:potentialnew cropforthesoutheasternUnitedStates.Pages597 599inNewCrops.J.JanickandJ.E. Simon,eds.Wiley,NewYork,NY. Poppi,D.P.,andB.W.Norton.1995.Intake oftropicallegumes.Pages173 189inTropical LegumesinAnimalNutrition.J.P.F.DMello,andC.Devendra,eds.CABIntl.,Oxon, U.K. Poppi,D.P.,B.W.Norton,D.J.Minston,andR.E.Hendricken.1980.Thevalidityofthecritical sizetheoryforparticle sleavingtherumen.J.Agric.Sci.94:275 280. Pott,A.,andL.R.Humphreys.1983.Persistenceandgr owthof Lotononisbainesii Digitaria decumbens pastures. J.ofAgric.Sci. 101: 1 7. Prevatt,W.2008.BudgetsformajorforagecropsinAlabama. http://www.ag.auburn.edu/agec//pubs/budgets/2008/forcrop08.php AccessedApr.8, 2008. Prichard,D.L.,D.D.Hargrove,T.A.Olson,andT.T.Marshall.1989.Effectsofcreepfeeding, zeranolimplantsandbreedtypeonbeefcattleproduction.I.Calfand cowperformance.J. Anim.Sci.67:609 616. Prine,G.M.,andE.C.French.1999.NewForage,Grain,andEnergyCropsforHumidLower South,UnitedStates.Pages60 65inPerspectivesonnewcropsandnewuses.J.Janick, ed.ASHSPress,Alexandria,VA. Pr ine,G.M.,L.S.,Dunavin,J.E.,MooreandR.D.Roush.1981.Florigrazerhizomapeanut a perennialforagelegume.Univ.ofFlorida,FloridaAgric.Exp.Stn.Circ.S 275.Univ. Florida,Gainesville. Rao,S.C.,S.W.ColemanandH.S.Mayeux.2002.Foragepro ductionandnutritivevalueof selectedpigeonpeaecotypesinthesoutherngreatplains.CropSci.42:1259 1263. Rao,S.C.,W.A.Phillips,H.S.MayeuxandS.C.Phatak.2003.Potentialgrainandforage productionofearlymaturingpigeonpeainthesouthern greatplains.CropSci.43:2212 2217. Reddy,N.R.,M.D. Pierson,S.K. Sathe,andD.K. Salunkhe.1985. Drybeantannins:Areviewof nutritionalimplications.J.oftheAm.OilChemistsSoc.62:541 549. Redfearn,D.D.,andC.J.Nelson.2003.Grassesfors outhernareas.Pages153 154inForages: AnIntroductiontoGrasslandAgriculture.6thed.R.FBarnes,C.J.Nelson,M.Collins, andK.J.Moore,eds.IowaStateUniv.Press,Ames,IA. Redmon,L.2002.ForagesforTexas.TexasA&MUniv.,TexasCoop.Ext .Sys.SoilCropSci. Comm.SCS 2002 14.Overton,TX. Reed,J.D.1995.Nutritionaltoxicologyoftanninsandrelatedpolyphenolsinforagelegumes.J. Anim.Sci.74:1516 1528.

PAGE 167

167 Remanandan,P.1990.Pigeonpea:geneticresources.Pages89 115inThePigeonp ea.Y.L. Nene,S.D.Hall,andV.K.Sheila,eds.CABIntl.:Intl.CropsRes.Inst.fortheSemi Arid Tropics,Univ.Press,Cambridge,UK. Reynolds,C.K.1995.Quantitativeaspectsoflivermetabolisminruminants.Pages351 371in RuminantPhysiology:Di gestion,Metabolism,GrowthandReproduction:Proc.8thIntl. Symp.Rumin.Physiol.W.V.Engelhardt,S.Leonhard Marek,G.Breves,andD. Giesecke,eds.FerdinandEnkeVerlag,Stuttgardt,Germany. Reynolds,C.K.,P.C.Aikman,B.Lupoli,D.J.Humphries,an dD.E.Beever.2003.Splanchnic metabolismofdairycowsduringthetransitionfromlategestationthroughearlylactation. J.DairySci.86:1201 1217. Robinson,O.W.,M.K.M.Yusuff,andE.U.Dillard.1978.MilkproductioninHerefordcows:I. Meansandco rrelations.J.Anim.Sci.47:131 136. Romero,F.,H.H.VanHorn,G.M.Prine,andE.C.French.1987.Effectofcuttingintervalupon yield,compositionanddigestibilityofFlorida77alfalfaandFlorigrazerhizomapeanut.J. Anim.Sci.65:786 796. Ruiz,M. ,E.Bernal,C.R.Staples,L.E.Sollenberger,andR.N.Gallaher.1995. Effectofdietary neutraldetergentfiberconcentrationandforagesourceonperformanceoflactatingcows J. DairySci.78:305 319. Said,A.N.,andA.Tolera.1993.Thesupplementary valueofforgelegumehaysinsheep feeding:feedintake,nitrogenretentionandbodyweightchange.Livest.Prod.Sci.33:229 237. Sage,R.F.,D.A.Wedin,andL.Meirong.1999.ThebiogeographyofC4photosynthesis:patterns andcontrollingfactors.Page s313 373inC4PlantBiology.R.F.SageandR.K.Monson, eds.AcademicPress,SanDiego,CA. Satter,L.D.,andR.E.Roffler.1975.Nitrogenrequirementandutilizationindairycattle.J.Dairy Sci.58:1219 1237. Satter,L.D.,andL.L.Slyter.1974.Effec tofammoniaconcentrationonrumenmicrobialprotein production invitro. Brit.J.Nutr.32:199 208. Seglar,B.2003.Fermentationanalysisandsilagequalitytesting.Pages119 136inProc.ofthe MinnesotaDairyHealthConf.Univ.MN.Minneapolis,MN. S eiter,S.,C.E.Altemose,andM.H.Davis.2004.Foragesoybeanyieldandqualityresponsesto plantdensityandrowdistance.AgronJ.96:966 970. Sheaffer,C.C.,J.H.Orf,T.E.Devine,andJ.G.Jewett.2001.Yieldandqualityofforage soybean.Agron.J .93:99 106.

PAGE 168

168 Sollenberger,L.E.,C.S.Jones,Jr.,andG.M.Prine.1989.Animalperformanceondwarf elephantgrassandrhizomapeanutpastures.Pages1189 1190inProc.26 th Intl.Grassl. Cong.,Nice,France. Sollenberger,L.E.,andM.Collins.2003.Legu mesforsouthernareas.Pages191 213in Forages:AnIntroductiontoGrasslandAgriculture.6thed.R.F.Barnes,C.J.Nelson,M. Collins,K.J.Moore,eds.IowaStateUniv.Press,Ames,IA. Soto Navarro,S.A.,M.H.Knight,G.P.Lardy,M.L.Bauer,andJ.S. Caton.2004.Effectoffiber basedcreepfeedonintake,digestion,ruminalfermentation,andmicrobialefficiencyin nursingcalves.J.Anim.Sci.82:3560 3566. Staples ,C.R., S.M.Emanuele, andG.M.Prine.1997. IntakeandnutritivevalueofFlorigra ze rhizomapeanutsilageforlactatingdairycows.J. DairySci.80:541 549. tMannetje,L.1997.HarryStobbsmemoriallecture,1994:Potentialandprospectsoflegume basedpasturesinthetropics.Trop.Grassl.31:81 94. Taiz,L.,andE.Zeiger.2002.P lantPhysiology.Thirded.SinauerAssoc.,Inc.Sunderland,MA. Tamminga,S.1979.Proteindegradationintheforestomachsofruminants.J.Anim.Sci. 49:1615 1630. Tarr,S.R.,D.B.Faulkner,D.D.Buskirk,F.A.Ireland,D.F.Farrett,andL.L.Berger.1994. The valueofcreepfeedingduringthelast84,56,or28dayspriortoweaningongrowth performanceofnursingcalvesgrazingendophyte infectedtallfescue.J.Anim.Sci. 72:1084 1094. Terrill,T.H.,A.M.Rowan,G.B.Douglas,andT.N.Barry.1992.Deter minationofextractable andboundcondensedtanninconcentrationsinforageplants,proteinconcentratemealsand cerealgrains.J.Sci.FoodAgric. 58: 321 329. Tjandraatmadja,M.,L.C.Macrae,andB.W.Norton.1993.Digestionbysheepofsilages prepared frommixturesoftropicalgrassesandlegumes.J.Agric.Sci.120:407 415. Tournas,V.,M.E.Stack,P.B.Mislivec,H.A.Koch,andR.Bandler.1999.Yeasts,moldsand mycotoxins.In"FoodandDrugAdministrationBacteriologicalAnalyticalManual". AOACInt l.,Gaithersburg,MD. Troedson,R.J.,E.S.Wallis,andL.Singh.1990.Pigeonpea :adaptation.Pages159 177in The Pigeonpea.Y.L.Nene,S.D.HallS.D.,andV.K.Sheila,eds.CABIntl.:Intl.CropsRes. Inst.fortheSemi AridTropics,Univ.Press,Camb ridge,UK. Troelsen,J.E.,andJ.B.Campbell.1968.Voluntaryconsumptionofforagebysheepandits relationtothesizeandshapeofparticlesinthedigestivetract.Anim.Prod.10:289.

PAGE 169

169 Ulyatt,M.J.,D.W.Dellow,A.John,C.S.W.Reid,andG.C.Waghorn. 1986.Contributionof chewingduringeatingandruminationtotheclearanceofdigestafromthe ruminoreticulum.Pages498 515inControlofDigestionandMetabolisminRuminants. L.P.Milligan,W.L.Grovum,andA.Dobson,eds.Prentice Hall,EnglewoodCl iffs,NJ. USDA.2001.CharacteristicsandProductionCostofU.S.Cow CalfOperations. www.ers.usda.gov/publications/sb974 3/sb974 3.pdf Accessed Mar.17, 2008. Utley,P.R.,H.D.Cha pman,W.G.Monson,W.H.MarchantandW.C.McCormick.1974. Coastcross 1bermudagrass,CoastalbermudagrassandPensacolabahiagrassassummer pastureforsteers.J.Anim.Sci.38:490 495. Umana,R.,C.R.Staples,D.B.Bates,C.J.Wilcox,andW.C.Mahanna. 1991.Effectsof microbialinoculantsand(or)sugarcanemolassesonthefermentation,aerobicstabilityand digestibilityofbermudagrassensiledattwomoisturecontents.J.Anim.Sci.69:4588 4601. Valencia,E.,R.RamosSantana,A.Rodriguez,B.Min,a ndK.Hernandez.2007.Chemical compositionandingestionoftropicalforagesbylambs.Page17inProc.JointAFGCand NEBCSAConference,StateCollege,PA. VanSoest,P.J.1994.NutritionalEcologyoftheRuminant.2nded.CornellUniv.Press,Ithaca, N Y. VanSoest,P.J.,J.B.Robertson,andB.A.Lewis.1991.Methodsfordietaryfiber,neutral detergentfiberandnon starchpolysaccharidesinrelationtoanimalnutrition.J.DairySci. 74:3568 3597. VanSoest,P.J.,R.H.Wine,andL.A.Moore.1966.Est imationofthefreedigestibilityofforages bytheinvitrodigestionofcellwails.Page438inProc.10thIntl.Grassl.Congr., Helsinki,Finland. vonCaemmerer,S.2000.BiochemicalModelsofLeafPhotosynthesis.CSIRO,Melbourne, Australia. Waghorn, G.C.,A.John,W.T.Jones,andI.D.Shelton.1987.Nutritivevalueof Lotus corniculatus L.containinglowandmediumconcentrationsofcondensedtanninsforsheep. Proc.N.Z.Soc.Anim.Prod.47:25 30. Waghorn,G.C.,I.D.Shelton,andV.J.Thomas.1989.P articlebreakdownandrumendigestionof freshryegrass( Loliumperenne L.)andlucerne( Medicagosativa L.)fedtocowsduringa restrictedfeedingperiod.Br.J.Nutr.61:409 423. Waghorn,G.C.,I.D.Shelton,W.C.McNabb,andS.N.McCutcheon.1994.Eff ectsof condensedtanninsinLotuspedunculatusonitsnutritivevalueforsheep.2.Nitrogenous aspects.J.Agric.Sci.123:109 119.

PAGE 170

170 Weder,C.E.,T.DelCurto,T.Svejar,J.R.Jaeger,andR.K.Bailey.1999.Influenceof supplementalalfalfaqualityonthe intake,use,andsubsequentperformanceofbeefcattle consuminglow qualityroughages.J.Anim.Sci.77:1266 1276. WeinbergZ.G.,G.Ashbell,A.Azrieli,andI.Brukental.1993a.Ensilingpeas,ryegrassand wheatwithadditivesoflacticacidbacteria(LA B)andcellwalldegradingenzymes.Grass ForageSci.48:70 78. Weinberg,Z.G.,G.Ashbell,Y.Hen,andA.Azrieli.1993b.Theeffectofapplyinglacticacid bacteriaatensilingontheaerobicstabilityofsilages.J.Appl.Bacteriol.75:512 518. William s,M.J.,andA.C.Hammond.1999.Rotationalvs.continuousintensivestocking managementofbahiagrasspastureforcowsandcalves.Agron.J.91:11 16. Williams,M.J.,C.C.Chase,andA.C.Hammond.2002.Dietqualityandperformanceofheifers inthesubtr opics.Agron.J.94:88 95. Williams,M.J.,C.C.Chase,Jr.,andA.C.,Hammond.2004.Performanceofcowsandtheir calvescreep grazedonrhizomaperennialpeanut.Agron.J.96:671 676. Wilman,D.,E.J.Metengeti,andG.Moseley.1996.Physicalstructure of12foragespeciesin relationtorateofintakebysheep.J.Agric.Sci.126:277 285. Wilson,J.R.1994.Cellwallcharacteristicsinrelationtoforagedigestionbyruminants.J.Agric. Sci.122:173 182. Wilson,J.R.,D.E.Akin,M.N.McLeod,andD.J. Minson.1989.Particlesizereductionofthe leavesofatropicalgrassandatemperategrassbycattle.II.Relationofanatomical structuretotheprocessofleafbreakdownthroughchewinganddigestion.Grassand ForageSci.44:65 75. Woclawek Potocka, I.,M.M.Bah,A.Korzekwa,M.K.Piskula,W.Wiczkowski,A.Depta,and D.J.Skarzynski.2005. Soybean derivedphytoestrogensregulateprostaglandinsecretionin endometriumduringcattleestrouscycleandearlypregnancy.Exp.BiologyandMedicine. 230:189 199. Woodruff,J.M.2007.Georgiasoybeanoutlook. www.caes.uga.edu/commodities/fieldcrops/soybeans/newsletters/2007/snl0307.pdf AccessedApr.7, 2008. Woolford,M.K.1975.Microbiologicalscreeningofthestraightchainfattyacids(C 1 C 12 )as potentialsilageadditives.J.Sci.FoodAgric.26:219 228. Woolford,M.K.1984.TheFermentationofSilage.MicrobiologySeries.Vol.14.Marcel Dekker,Inc.,Ne wYork,NY. Wylie,C.E.,andJ.A.Schaller.1939. Haydryingsystemsforsmallfarms.J.Anim.Sci.1939:60 67.

PAGE 171

171 Yang,C.M.J.2005.Proteolysis,fermentationefficiency,andinvitroruminaldegradationof peanutstoverensiledwithraworheatedcorn.J.DairySci.88:2903 2910.

PAGE 172

172 BIOGRAPHICALSKETCH JamieLeeFosterwasborninHouston,Texas,andherfamilynowresidesinCedarPark, Texas.SheattendedWestwoodHighSchoolinAustin,Texas,graduatingin1998.Inhigh schoolsheactivelyparticipatedinFFAasachapteroffice randshereceivedtheLoneStar FarmerStateFFADegreein1997.Afterhighschool,sheattendedherfirstyearofcollegeat AustinCommunityCollegewithprizemoneyawardedfromshowinglambs.Shethen transferredtoTarletonStateUniversity,Stephe nville,Texas,wheresheearnedherBachelorof Sciencedegreeinanimalsciencein2002.WhileatTarleton,shewasemployedattheTexas AgriculturalResearchandExtensionCenterasastudentworker.Thisopportunityprovidedher withaninsightinto agriculturalresearchinthelaboratoryandthefield.Dr.JamesP.Muir,her employer,fundedhermastersdegreeresearchatthecenter.SheattendedTexasA&M University,CollegeStation,Texas,andobtainedherMasterofSciencedegreeinagronomyin Augustof2004.DuringhertimeatTexasA&M,shedevelopedandrefinedherteachingskills asateachingassistantfortheIntroductiontoSoilSciencecourseandbeganhertrainingasa scientistbydesigningandconducting2experiments,oneofwhich waspublishedinAnimal FeedScienceandTechnologyin2007. In2004,JamiewasacceptedintothePh.D.programintheDepartmentofAnimalSciences undertheguidanceofDrs.AdegbolaAdesoganandJeffreyCarter,andshewasawardeda UniversityofFlor idaAlumniFellowship.DuringherPh.D.program,JamiewontheRobertF. BarnesGraduateStudentCompetitionatthe2006InternationalCropScienceSocietyofAmerica meeting.SheservedasateachingassistantinseveralcoursesincludingIntroductiont oAnimal ScienceandthegraduatelevelAdvancedMethodsinNutritionTechniquescourse.Sheguest lecturedforseveralcoursesincludingthegraduatelevelRuminantNutritioncourse.Sherefined acondensedtanninlaboratoryanalysisprocedureandhelpe dherfellowanimalscienceand

PAGE 173

173 agronomygraduatestudentswithmanytypesofexperimentsincludingsomeonequinebehavior, dairycowfeedingandmilking,andforagefieldwork. JamieisacertifiedmemberoftheAmericanRegistryofAnimalScientists,th eCrop ScienceSocietyofAmerica,andtheAmericanSocietyofAnimalScience.Shewasinducted intoAlphaZetaandGammaSigmaDeltaagriculturalhonorsocieties.Throughouthergraduate trainingshecontinuedherservicetoSigmaAlpha,anationalagri culturalsorority,asaNational BoardDirector(2002 2003),NationalBoardVicePresident(2003 2005),andNationalBoard President(2005 2007).ShehasworkedwithAgintheClassroomsince1999andservesas assistantconferencechairforFloridaAgri Women.OntheUniversityofFloridacampus,Jamie wasanactivememberofTheAnimalSciencesGraduateStudentAssociation.