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Mineral concentrations of annual cool season pasture forages in north Florida during the winter-spring grazing season : II. trace minerals
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2009 Florida Beef Report
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Chelliah, G.
Myer, Bob
Carter, Jeff
McDowell, Lee
Wilkinson, Nancy
Blount, Ann
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Gainesville, Fla.
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Mineral Concentrations of Annual Cool Season Pasture Forages in North
Florida during the Winter-Spring Grazing Season: II. Trace Minerals

G. Chelliah1
Bob Myer
Jeff Carter
Lee McDowell
Nancy Wilkinson
Ann Blount

Pasture forage species and blend, pasture establishment method, year, and month of grazing season can
influence concentrations of copper (Cu), zinc (Zn), selenium (Se), cobalt (Co), and, in particular,
manganese (Mn) and iron (Fe) in annual cool-season grass pasture forage.


Summary
Concentrations of selected trace minerals (Cu,
Fe, Zn, Mn, Co, Se) were determined from
annual cool-season grass pasture forages over
four consecutive winter-spring grazing seasons
(2001-2005). Twice monthly forage samples
were taken from eight experimental pastures
used in beef cattle grazing trials. Two, 2-yr
experiments were conducted; animal and
pasture data were reported previously. Each
experiment was of a similar 2x2 design
comparing clean-tilled vs. sod-seeded pastures
with two annual forage combinations (Study 1,
rye + oats vs. rye + oats + ryegrass; Study 2,
oats + ryegrass vs. ryegrass only). Pastures
were planted in Oct or Nov, and grazed
(sampled) oi,,iig Nov, Dec, Jan or Feb and
ending Apr or May. The overall mean
concentrations of pasture forage for Exp. 1 and
2 respectively were (ppm of dry matter): Cu, 6.4
and 5.2; Fe, 88 and 68; Zn, 38 and 42; Mn, 105
and 114; Co, 0.06 and 0.06; and Se, 0.05 and
0.06. Year affected (P<0.05) forage Cu, Fe, Zn,
and Se in Exp. 1 and Fe and Zn in Exp. 2.
Pasture establishment method affected (P<0.05)
Cu, Fe, Zn, and Mn in Exp. 1 and Mn and Se in
Exp. 2. Forage treatment affected (P<0.05) Zn
in Exp. 1 and Cu, Fe, Zn, Mn, and Co in Exp. 2.
Sampling month affected (P<0.05) all minerals
in both experiments except Cu and Zn in Exp. 2;
monthly Se and Co were not evaluated due to


limited analyses. Results indicate that forage
type, pasture establishment method, year, and
month of grazing season can affect
concentrations of trace minerals of annual cool-
season grass pasture forages in the southeastern
USA.

Introduction
Cool-season annual grasses, such as oats (Avena
sativa), rye (Secale cereale) and annual ryegrass
(Lolrum multifloram) are commonly planted to
provide forage for grazing by beef cattle during
the late fall to spring period in the southeastern
USA when permanent warm-season grass
pastures are dormant. Depending on moisture
and weather, the grazing period can start as early
as late November and last until early June, but
the start can be as late as February and can end
as early as late April. The annual forages are
planted during the fall (Oct or Nov), and can be
seeded directly into dormant warm-season
pasture (sod-seeding) or planted into a clean-
tilled, prepared seedbed. These forages are
highly digestible and high in energy and protein;
however, there is limited information in regards
to concentration of various nutritionally
important minerals. The purpose of this study
was to measure monthly concentrations of
selected macro and trace minerals in annual
cool-season grass pasture forage of various


2009 Florida BeefReport










combinations that were either sod-seeded or
planted into a clean-tilled, prepared seedbed
during the late fall-winter-spring grazing season
in north Florida.

This report will present the results of the trace
minerals of Cu, Zn, Fe, Mn, Co and Se. A
companion report (Chelliah et al., 2009) will
present results of analyses of selected macro
minerals and is presented elsewhere in the 2009
Florida Beef Report.

Procedures
Pasture forage mineral concentrations were
determined as part of a grazing study. The study
consisted of two cool-season beef cattle grazing
experiments conducted at the North Florida
Research and Education Center (NFREC) of the
University of Florida located at Marianna (31 N
Lat.). Each experiment lasted two yr, resulting in
four consecutive yr of testing from 2001 to 2005
during the late fall-winter-spring grazing season.
Trace (micro) mineral concentrations were
determined from forage samples taken from
eight, 3.2 ac experimental pastures per yr used in
the two grazing experiments.

The two, two-year studies conducted were each
of a similar 2x2 design comparing clean-tilled
vs. sod-seeded pastures with two different forage
combinations (simple vs. more complex blend;
Exp. 1 small grains only rye and oats vs. small
grains plus ryegrass; Exp. 2, ryegrass only vs.
ryegrass plus oats). There were two pastures per
treatment combination per year within each
experiment. Pastures were planted in October or
November of each year, and grazed and sampled
starting November, December, January or
February, and ending April or May (the start and
end varied between years due to weather
conditions pastures were grown under dry land
conditions).

Pastures were sampled twice mo and samples
were pooled by month for mineral analyses. Not
all months were represented for each yr,
however, the months of February, March and
April were represented for each yr of each
experiment and were used in statistical analyses
to evaluate the effect of yr, forage type, and
pasture establishment method. Due to high
costs, only a limited number of samples, chosen


at random, were analyzed for Se and Co for each
yr in each experiment. Further information about
planting, fertilization, and management of
pastures is presented in a companion paper
published elsewhere in the 2009 Florida Beef
Report (Chelliah et al., 2009). Cattle were
provided a free choice mineral supplement at all
times while grazing (Purina Dixie H/M H/SE,
Purina Mills, St. Louis, MO).

Data were analyzed as a 2x2 randomized
complete block design. The models evaluated
pasture forage treatment and pasture
establishment method as fixed effects, and yr as
random. Monthly mineral concentrations for
each experiment also were analyzed using
repeated measures model with mo as the
repeated measure. The experimental unit was the
individual pasture.

Results
Animal and pasture results were reported
previously (Myer and Blount, 2005 and 2007).
Cool-season annual grass species chosen reflect
what is commonly grown in the Southern
Coastal Plain region of the US. Most cool-
season annual pastures planted, however, are
mono-crops in this region. Average monthly
rainfall and daily temperatures over the four
study yr during October to May period were
similar to the 30-yr average at Marianna, except
for rainfall in January and May where amounts
averaged 30 to 50% less over the four yrs.
October, November, April and May tended to be
warmer than the 30-yr average. As expected,
there was yr to yr variation which probably
affected pasture forage mineral concentrations
noted for yr to yr. As such, results were
averaged over yrs as most producers are
interested in what may be expected for an
average yr.

Pasture establishment method affected (P<0.05)
forage concentrations of Cu, Zn, Fe, and Mn in
Exp. 1, and Mn and Se in Exp. 2 (Table 1).
Pasture forage treatment affected (P<0.05)
forage concentrations of Zn in Exp. 1, and Cu,
Zn, Fe, Mn, and Co in Exp. 2 (Table 1).

Year affected (P<0.05) Cu, Zn, Fe and Se
pasture forage concentrations in Exp. 1, but only
affected Zn and Fe in Exp. 2 (means are not


2009 Florida BeefReport










shown). No pasture establishment method by would be deficient, Zn would be marginal, and
forage treatment or year by treatment Fe and Mn would be adequate (Table 3).
combination interactions (P>0.05) were noted.

Month within yr affected (P<0.05) pasture
forage concentrations of Cu, Zn, Fe and, Mn in
Exp. 1 but only Fe and Mn in Exp. 2 (Table 2).
Month by mo results of Se and Co are
incomplete due to limited number of samples
analyzed. In general, forage concentrations of
Fe decreased and Mn increased as the grazing
season progressed (Table 2).Considerable
variation in concentrations of the trace minerals
in the pasture forage samples, however, were
noted within experiments (Table 3).

Results indicated that annual cool-season pasture
forage type, pasture establishment method, and,
yr, while not consistent between the
experiments, can influence pasture forage
concentrations of Cu, Zn, Fe, Mn, Co and Se.
The significant differences noted due to forage
treatment and pasture establishment method;
however, were small. Again, while not
consistent, pasture forage trace mineral
concentrations can also be influenced by mo
during the grazing season, especially Fe and Mn.
The high Fe early on in the grazing season noted
in Exp. I but not Exp. 2 may have been the result
of soil contamination. Soil, which is high in Fe,
can splash on to the plant after a rain.

Overall mean pasture forage concentrations and
variation noted for the trace minerals measured
is summarized in Table 3. From the results
obtained in both experiments, concentrations
(mean one standard deviation; dry matter
basis) in cool-season annual grass forages
evaluated averaged 5.8 0.8 ppm for Cu, 78
14 ppm for Fe, 40 4 ppm for Zn, 110 14
ppm for Mn, 0.04 to 0.06 0.02 ppm for Co,
and 0.055 0.01 ppm for Se. The ranges for Cu
and Se are similar to those previously reported;
Fe is at the low end, Zn at the high end, and Mn
above (Table 3). However, it should be
emphasized that there was much variation in the
concentration of each mineral evaluated,
especially, Fe.

Overall, for beef cattle grazing annual cool-
season grass pastures, forage Cu, Se and Co


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Literature Cited
'Chelliah, G., et al. 2009 Florida Beef Report.
Ensminger, M. E., et al. 1990. Feeds and Nutrition. The Ensminger Publishing Co., Clovis, CA,
USA. pp 1265-1511.
Myer, R. O. and A. R. Blount. 2005 Florida Beef Report. pp 23-27.
Myer, B. and A. Blount. 2007 Florida Beef Report. pp 19-24.
NRC. 2000. Nutrient Requirements of Beef Cattle. 7th rev. ed. Nat'l. Acad. Sci.,
Washington, DC, USA.




Acknowledgement
The assistance of Harvey Standland, John Crawford, Meghan Brennan, Mary Maddox, Tina,
Gwin, Mary Chambliss, Jeff Jones, and the staff at the NFREC Beef Unit is gratefully
acknowledged. Partial support was provided by Orange Hill Soil Conservation District,
Chipley, FL.




'G. Chelliah, Former Graduate Student; Bob Myer, Professor, UF-IFAS, North Florida Research and
Education Center (NFREC), Marianna, FL; Jeff Carter, Former Assistant Professor, UF-IFAS,
NFREC, Marianna; Lee McDowell, Professor Emeritus, UF-IFAS, Department of Animal Sciences,
Gainesville, FL, Nancy Wilkinson, Chemist, UF-IFAS, Department of Animal Sciences, Gainesville,
Fl; and Ann Blount, Associate Professor, UF-IFAS, NFREC, Marianna, FL.


2009 Florida BeefReport



















Table 1. Trace mineral concentrations of annual cool-season grass pasture forages during the late
fall-winter-spring grazing season in north Florida (ppm of dry matter).

Cultivation Forage Trt. Significanceg
Mineral Exp.a SSb PSc Simpled Blende SEMI Cult.h Forage' CxF1
Cu 1 6.6 5.7 5.9 6.4 0.02 ** NS NS
2 5.1 5.3 5.9 4.5 0.03 NS ** NS
Fe 1 79 98 92 84 4 NS NS
2 70 67 78 58 3 NS ** NS
Zn 1 31 45 36 41 2 ** NS
2 41 44 47 38 2 NS ** NS
Mn 1 120 91 100 110 6 ** NS NS
2 103 127 127 102 4 ** ** NS
Co 1 0.07 0.05 0.06 0.05 0.01 NS NS NS
2 0.06 0.06 0.09 0.04 0.01 NS NS
Se 1 0.05 0.05 0.05 0.05 0.003 NS NS NS
2 0.04 0.07 0.06 0.05 0.005 ** NS NS
aExp. 1, 2001-2002 and 2002-2003 grazing seasons; and Exp. 2, 2003-2004 and 2004-2005.
bSS = sod-seeded pastures
"PS = prepared seedbed (clean-tilled) pastures.
dSimple blend or mono-culture of forage species in pastures (Exp. 1, small grains rye and oats; Exp. 2,
ryegrass only).
eBlend of forage species in pastures (Exp. 1, small grains plus ryegrass; Exp. 2, oats plus ryegrass).
fStandard error of the mean; n = 8.
gSignificance of difference; ** = highly significantly different (P< 0.01), *= significantly different (P< 0.05),
and NS = non-significant (P> 0.05).
hPasture establishment method (PS vs. SS).
'Pasture forage treatment (simple vs. blend).
1Establishment method by forage treatment interaction.


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Table 2. Monthly concentrations of trace minerals in annual cool-season pasture forages during the
late fall-winter-spring grazing season in north Florida (ppm of dry matter).

Sampling month
Mineral Exp.a Nov Dec Jan Feb Mar Apr May SEMb Significance0
Cu 1 5.8 7.7 8.2 6.1 6.0 6.4 5.5 0.4 **
2 5.7 4.9 5.1 5.0 5.5 5.3 4.8 0.5 NS
Fe 1 190 126 178 98 75 92 105 13 **
2 85 83 83 90 82 64 60 12 **
Zn 1 30 33 41 37 36 41 60 3 **
2 41 39 42 48 40 42 46 5 NS
Mn 1 82 95 111 106 105 105 125 9 **
2 78 107 96 91 108 112 124 10 **
Co 1 -- 0.05 -- 0.03 0.02 0.08 0.09 0.03 *
2 -- -- 0.07 0.07 0.12 0.05 NS
Se 1 -- 0.05 -- 0.05 0.04 0.06 0.06 0.02 NS
2 -- -- -- -- 0.07 0.05 0.06 0.01 NS
a Exp. 1, 2001-2002 and 2003-2003 grazing seasons; and Exp. 2, 2003-2004 and 2004-2005.
bStandard error of the mean; average n = 8 (average n = 3 for Co and Se).

"Significance due to month within experiment; ** = highly significant (P<0.01), = significant (P<0.05), and
NS = non-significant (P> 0.05).


Table 3. Overall means and ranges of trace mineral concentrations of annual cool-season annual
grass pasture forages from each two-year experiment (ppm, dry matter basis).

Mineral Exp.a Meanb 1S.D.C Ranged Requiremente Reported
Cu 1 6.4 0.5 4.0 to 9.9 10 4 to 8
2 5.2 0.9 4.0 to 9.4
Fe 1 88 15 56 to 242 50 101 to 367
2 68 13 68 to 156
Zn 1 38 4 13 to 56 30 25 to 30
2 42 4 29 to 74
Mn 1 105 19 56 to 171 40 42 to 66
2 114 9 62 to 160
Co 1 0.06 0.02 0.02 to 0.10 0.10
2 0.06 0.02 0.03 to 0.13
Se 1 0.05 0.01 0.03 to 0.07 0.10 0.07
2 0.06 0.01 0.04 to 0.08
aExp. 1, 2001-2002 and 2002-2003 grazing seasons; and Exp. 2, 2003-2004 and 2004-2005.
bOverall mean across all treatments (n = 24; 8 for Co and Se).

"One standard deviation.
dLowest or highest monthly concentration obtained from a treatment within year within experiment (n = 2).
eSuggested requirement for growing beef cattle heifers (500 to 900 lb; NRC 2000).

fOther reported concentrations for rye, oats and ryegrass fresh forage (dry matter basis); data from Ensminger et
al., 1990, and NRC, 2000.


2009 Florida BeefReport




Full Text

PAGE 1

Mineral Concentrations of Annual Cool Season Pasture Forages in North Florida during the Winter Spring Grazing Season: II. Trace Minerals G. Chelliah 1 Bob Myer Jeff Carter Lee McDowell Nancy Wilkinson Ann Blount Summary Concentrations of selected trace minerals (Cu, Fe, Zn, Mn, Co, Se) were determined from annual cool-season grass pasture forages over four consecutive winter-spring grazing seasons (2001-2005). Twice monthly forage samples were taken from eight experimental pastures used in beef cattle grazing trials. Two, 2-yr experiments were conducted; animal and pasture data were reported previously. Each experiment was of a similar 2x2 design comparing clean-tilled vs. sod-seeded pastures with two annual forage combinations (Study 1, rye + oats vs. rye + oats + ryegrass; Study 2, oats + ryegrass vs. ryegrass only). Pastures were planted in Oct or Nov, and grazed (sampled) starting Nov, Dec, Jan or Feb and ending Apr or May. The overall mean concentrations of pasture forage for Exp. 1 and 2 respectively were (ppm of dry matter): Cu, 6.4 and 5.2; Fe, 88 and 68; Zn, 38 and 42; Mn, 105 and 114; Co, 0.06 and 0.06; and Se, 0.05 and 0.06. Year affected (P<0.05) forage Cu, Fe, Zn, and Se in Exp. 1 and Fe and Zn in Exp. 2. Pasture establishment method affected (P<0.05) Cu, Fe, Zn, and Mn in Exp. 1 and Mn and Se in Exp. 2. Forage treatment affected (P<0.05) Zn in Exp. 1 and Cu, Fe, Zn, Mn, and Co in Exp. 2. Sampling month affected (P<0.05) all minerals in both experiments except Cu and Zn in Exp. 2; monthly Se and Co were not evaluated due to limited analyses. Results indicate that forage type, pasture establishment method, year, and month of grazing season can affect concentrations of trace minerals of annual coolseason grass pasture forages in the southeastern USA. Introduction Cool-season annual grasses, such as oats ( Avena sativa ), rye ( Secale cereale ) and annual ryegrass ( Lolrum multifloram) are commonly planted to provide forage for grazing by beef cattle during the late fall to spring period in the southeastern USA when permanent warm-season grass pastures are dormant. Depending on moisture and weather, the grazing period can start as early as late November and last until early June, but the start can be as late as February and can end as early as late April. The annual forages are planted during the fall (Oct or Nov), and can be seeded directly into dormant warm-season pasture (sod-seeding) or planted into a cleantilled, prepared seedbed. These forages are highly digestible and high in energy and protein; however, there is limited information in regards to concentration of various nutritionally important minerals. The purpose of this study was to measure monthly concentrations of selected macro and trace minerals in annual cool-season grass pasture forage of various Pasture forage species and blend, pasture establishment method, year, and month of grazing season can influence concentrations of copper (Cu), zinc (Zn), selenium (Se), cobalt (Co), and, in particular, manganese (Mn) and iron (Fe) in annual cool season grass pasture forage.

PAGE 2

combinations that were either sod-seeded or planted into a clean-tilled, prepared seedbed during the late fall-winter-spring grazing season in north Florida. This report will present the results of the trace minerals of Cu, Zn, Fe, Mn, Co and Se. A companion report (Chelliah et al., 2009) will present results of analyses of selected macro minerals and is presented elsewhere in the 2009 Florida Beef Report. Procedures Pasture forage mineral concentrations were determined as part of a grazing study. The study consisted of two cool-season beef cattle grazing experiments conducted at the North Florida Research and Education Center (NFREC) of the University of Florida located at Marianna (31 N Lat.). Each experiment lasted two yr, resulting in four consecutive yr of testing from 2001 to 2005 during the late fall-winter-spring grazing season. Trace (micro) mineral concentrations were determined from forage samples taken from eight, 3.2 ac experimental pastures per yr used in the two grazing experiments. The two, two-year studies conducted were each of a similar 2x2 design comparing clean-tilled vs. sod-seeded pastures with two different forage combinations (simple vs. more complex blend; Exp. 1 small grains only rye and oats vs. small grains plus ryegrass; Exp. 2, ryegrass only vs. ryegrass plus oats). There were two pastures per treatment combination per year within each experiment. Pastures were planted in October or November of each year, and grazed and sampled starting November, December, January or February, and ending April or May (the start and end varied between years due to weather conditions pastures were grown under dry land conditions). Pastures were sampled twice mo and samples were pooled by month for mineral analyses. Not all months were represented for each yr, however, the months of February, March and April were represented for each yr of each experiment and were used in statistical analyses to evaluate the effect of yr, forage type, and pasture establishment method. Due to high costs, only a limited number of samples, chosen at random, were analyzed for Se and Co for each yr in each experiment. Further information about planting, fertilization, and management of pastures is presented in a companion paper published elsewhere in the 2009 Florida Beef Report (Chelliah et al., 2009). Cattle were provided a free choice mineral supplement at all times while grazing (Purina Dixie H/M H/SE, Purina Mills, St. Louis, MO). Data were analyzed as a 2x2 randomized complete block design. The models evaluated pasture forage treatment and pasture establishment method as fixed effects, and yr as random. Monthly mineral concentrations for each experiment also were analyzed using repeated measures model with mo as the repeated measure. The experimental unit was the individual pasture. Results Animal and pasture results were reported previously (Myer and Blount, 2005 and 2007). Cool-season annual grass species chosen reflect what is commonly grown in the Southern Coastal Plain region of the US. Most coolseason annual pastures planted, however, are mono-crops in this region. Average monthly rainfall and daily temperatures over the four study yr during October to May period were similar to the 30-yr average at Marianna, except for rainfall in January and May where amounts averaged 30 to 50% less over the four yrs. October, November, April and May tended to be warmer than the 30-yr average. As expected, there was yr to yr variation which probably affected pasture forage mineral concentrations noted for yr to yr. As such, results were averaged over yrs as most producers are interested in what may be expected for an average yr. Pasture establishment method affected ( P<0.05 ) forage concentrations of Cu, Zn, Fe, and Mn in Exp. 1, and Mn and Se in Exp. 2 (Table 1). Pasture forage treatment affected ( P<0.05 ) forage concentrations of Zn in Exp. 1, and Cu, Zn, Fe, Mn, and Co in Exp. 2 (Table 1). Year affected ( P<0.05) Cu, Zn, Fe and Se pasture forage concentrations in Exp. 1, but only affected Zn and Fe in Exp. 2 (means are not

PAGE 3

shown). No pasture establishment method by forage treatment or year by treatment combination interactions ( P>0.05 ) were noted. Month within yr affected ( P<0.05 ) pasture forage concentrations of Cu, Zn, Fe and, Mn in Exp. 1 but only Fe and Mn in Exp. 2 (Table 2). Month by mo results of Se and Co are incomplete due to limited number of samples analyzed. In general, forage concentrations of Fe decreased and Mn increased as the grazing season progressed (Table 2).Considerable variation in concentrations of the trace minerals in the pasture forage samples, however, were noted within experiments (Table 3). Results indicated that annual cool-season pasture forage type, pasture establishment method, and, yr, while not consistent between the experiments, can influence pasture forage concentrations of Cu, Zn, Fe, Mn, Co and Se. The significant differences noted due to forage treatment and pasture establishment method; however, were small. Again, while not consistent, pasture forage trace mineral concentrations can also be influenced by mo during the grazing season, especially Fe and Mn. The high Fe early on in the grazing season noted in Exp. I but not Exp. 2 may have been the result of soil contamination. Soil, which is high in Fe, can splash on to the plant after a rain. Overall mean pasture forage concentrations and variation noted for the trace minerals measured is summarized in Table 3. From the results obtained in both experiments, concentrations (mean one standard deviation; dry matter basis) in cool-season annual grass forages evaluated averaged 5.8 0.8 ppm for Cu, 78 14 ppm for Fe, 40 4 ppm for Zn, 110 14 ppm for Mn, 0.04 to 0.06 0.02 ppm for Co, and 0.055 0.01 ppm for Se. The ranges for Cu and Se are similar to those previously reported; Fe is at the low end, Zn at the high end, and Mn above (Table 3). However, it should be emphasized that there was much variation in the concentration of each mineral evaluated, especially, Fe. Overall, for beef cattle grazing annual coolseason grass pastures, forage Cu, Se and Co would be deficient, Zn would be marginal, and Fe and Mn would be adequate (Table 3).

PAGE 4

Literature Cited 1 Chelliah, G., et al. 2009 Florida Beef Report. Ensminger, M. E., et al. 1990. Feeds and Nutrition. The Ensminger Publishing Co., Clovis, CA, USA. pp 1265 1511. Myer, R. O. and A. R. Blount. 2005 Florida Beef Report. pp 23 27. Myer, B. and A. Blount. 2007 Florida Beef Report. pp 19 24. Washington, DC, USA. Acknowledgement The assistance of Harvey Standland, John Crawford, Meghan Brennan, Mary Maddox, Tina, Gwin, Mary Chambliss, Jeff Jones, and the staff at the NFREC Beef Unit is gratefully acknowledged. Partial support was provided by Orange Hill Soil Conservation District Chipley, FL. 1 G. Chelliah, Former Graduate Student; Bob Myer, Professor, UF IFAS, North Fl orida Research and Education Center (NFREC), Marianna, FL; Jeff Carter, Former Assistant Professor, UF IFAS, NFREC, Marianna; Lee McDowell, Professor Emeritus, UF IFAS, Department of Animal Sciences, Gainesville, FL, Nancy Wilkinson, Chemist, UF IFAS, Dep artment of Animal Sciences, Gainesville, Fl; and Ann Blount, Associate Professor, UF IFAS, NFREC, Marianna, FL.

PAGE 5

Table 1. Trace mineral concentrations of annual cool season grass pasture forages during the late fall winter spring grazing season in north Florida (ppm of dry matter). Cultivation Forage Trt. Significance g Mineral Exp. a SS b PS c Simple d Blend e SEM f Cult. h Forage i CxF j Cu 1 6.6 5.7 5.9 6.4 0.02 ** NS NS 2 5.1 5.3 5.9 4.5 0.03 NS ** NS Fe 1 79 98 92 84 4 NS NS 2 70 67 78 58 3 NS ** NS Zn 1 31 45 36 41 2 ** NS 2 41 44 47 38 2 NS ** NS Mn 1 120 91 100 110 6 ** NS NS 2 103 127 127 102 4 ** ** NS Co 1 0.07 0.05 0.06 0.05 0.01 NS NS NS 2 0.06 0.06 0.09 0.04 0.01 NS NS Se 1 0.05 0.05 0.05 0.05 0.003 NS NS NS 2 0.04 0.07 0.06 0.05 0.005 ** NS NS a Exp. 1, 2001 2002 and 2002 2003 grazing seasons; and Exp. 2, 2003 2004 and 2004 2005. b SS = sod seeded pastures c PS = prepared seedbed (clean tilled) pastures. d Simple blend or mono culture of forage species in pastures (Exp. 1, small grains rye and oats; Exp. 2, ryegrass only). e Blend of forage species in pastures (Exp. 1, small grains plus ryegrass; Exp. 2, oats plus ryegrass). f Standard error of the mean; n = 8. g Significance of difference; ** = highly significantly different ( P<0.01 ), = significantly different ( P<0.05 ), and NS = non significant ( P>0.05 ). h Pasture establishment method (PS vs. SS). i Pasture forage treatment (simple vs. blend). j Establishment method by forage treatment interaction.

PAGE 6

Table 2. Monthly concentrations of trace minerals in annual cool season pasture forages during the late fall winter spring grazing season in north Florida (ppm of dry matter). Sampling month Mineral Exp. a Nov Dec Jan Feb Mar Apr May SEM b Significance c Cu 1 5.8 7.7 8.2 6.1 6.0 6.4 5.5 0.4 ** 2 5.7 4.9 5.1 5.0 5.5 5.3 4.8 0.5 NS Fe 1 190 126 178 98 75 92 105 13 ** 2 85 83 83 90 82 64 60 12 ** Zn 1 30 33 41 37 36 41 60 3 ** 2 41 39 42 48 40 42 46 5 NS Mn 1 82 95 111 106 105 105 125 9 ** 2 78 107 96 91 108 112 124 10 ** Co 1 -0.05 -0.03 0.02 0.08 0.09 0.03 2 ----0.07 0.07 0.12 0.05 NS Se 1 -0.05 -0.05 0.04 0.06 0.06 0.02 NS 2 ----0.07 0.05 0.06 0.01 NS a Exp. 1, 2001 2002 and 2003 2003 grazing seasons; and Exp. 2, 2003 2004 and 2004 2005. b Standard error of the mean; average n = 8 (average n = 3 for Co and Se). c Significance due to month within experiment; ** = highly significant ( P<0.01 ), = significa nt ( P<0.05 ), and NS = non significant ( P>0.05 ). Table 3. Overall means and ranges of trace mineral concentrations of annual cool season annual grass pasture forages from each two year experiment (ppm, dry matter basis). Mineral Exp. a Mean b 1S.D. c Range d Requirement e Reported f Cu 1 6.4 0.5 4.0 to 9.9 10 4 to 8 2 5.2 0.9 4.0 to 9.4 Fe 1 88 15 56 to 242 50 101 to 367 2 68 13 68 to 156 Zn 1 38 4 13 to 56 30 25 to 30 2 42 4 29 to 74 Mn 1 105 19 56 to 171 40 42 to 66 2 114 9 62 to 160 Co 1 0.06 0.02 0.02 to 0.10 0.10 -2 0.06 0.02 0.03 to 0.13 Se 1 0.05 0.01 0.03 to 0.07 0.10 0.07 2 0.06 0.01 0.04 to 0.08 a Exp. 1, 2001 2002 and 2002 2003 grazing seasons; and Exp. 2, 2003 2004 and 2004 2005. b Overall mean across all treatments (n = 24; 8 for Co and Se). c One standard deviation. d Lowest or highest monthly concentration obtained from a treatment within year within experiment (n = 2). e Suggested requirement for growing beef cattle heifers (500 to 900 lb; NRC 2000). f Other reported concentrations for rye, oats and ryegrass fresh forage (dry matter basis); data from Ensminger et al., 1990, and NRC, 2000.