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Overseeding Bermudagrass pastures with winter annuals
Hay standards and infrared evaluation of Bermudagrass
Improving low quality hay with ammonia
The publications in this collection do
not reflect current scientific knowledge
or recommendations. These texts
represent the historic publishing
record of the Institute for Food and
Agricultural Sciences and should be
used only to trace the historic work of
the Institute and its staff. Current IFAS
research may be found on the
Electronic Data Information Source
site maintained by the Florida
Cooperative Extension Service.
Copyright 2005, Board of Trustees, University
Research Report NF84-5
FALL FORAGE FORUM
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SIXTH ANNUAL MEETING
JUL 1 ib:3
I.F.A.S.- Univ. of Florida
INSTITUTE OF FOOD AND AGRICULTURAL SCIENCES
UNIVERSITY OF FLORIDA
J.T. Woeste, Dean for Extension
F.A. Wood, Dean for Research
Proceedings of the Sixth Annual Fall Forage Forum
Several topics concerning bermudagrass are dis-
cussed in the proceedings. Each speaker on the program
has had many years of experience working with bermuda-
grass and the program should provide useful information
for farmers who use bermudagrass in their farm program.
D. L. Wrigh C. G. Chambliss
Dr. Bob Stanley, University of Florida -
Mr. Danny Stevens, Gilchrist County
Dr. Charlie Ruelke, University of Florida -
Dr. John Moore, University of Florida -
Dr. Bill Kunkle, University of Florida -
Overseeding Bermudagrass Pastures With Winter Annuals1
R. L. Stanley, Jr.2
The bermudagrasses make up one of the main perennial forage
species in the southeastern United States, particularly in the
Coastal Plains area. It has been estimated that approximately 10
million acres of Coastal Bermudagrass have been planted in the
southeastern U.S. (Dr. G. W. Burton, personal communication).
Bermudagrass begins to "green up" in March, but little grazing is
available until April. Usually, there is a peak production
period in mid-summer when rain showers become frequent enough to
maintain soil moisture levels necessary for good growth. Often
about 2/3 of the total forage produced during the season will be
in June, July, and August. After September 30 there is usually
very little, if any, forage produced. This means that for 6
months of the year (Oct. 1 Mar. 31) no forage is produced by
the bermudagrasses. Overseeding into the grass to make use of
the dormant period might deserve some consideration.
Manuscript prepared for Fall Forage Forum, Nov. 1, 1984 at
NFREC, Quincy, Fla.
Associate Professor (Associate Agronomist), North Florida
Research and Education Center, Quincy, Fla. 32351.
The following may be possible reasons to consider overseeding
1. Better utilization of land resources.
2. Increase forage production by extending grazing season.
3. Increase forage quality. The winter annual grasses and
clovers are much higher in quality and are available at
a critical time in production cycle of the cow.
4. Use of legumes can add nitrogen to the grass.
5. Grain (such as wheat) harvested can be a source of cash
to aid in cash flow.
We do not have a very wide choice of adapted cool season
annuals for seeding into bermudagrass sods. Some that have been
successful, along with management considerations, are discussed
In North Florida crimson and arrowleaf clovers are the
most adapted legumes for overseeding perennial grass
sods. Red clover and subterranean clovers also show
promise. Two of the major advantages to be gained by
using the clovers are the high quality of the forage
and the addition of nitrogen by the legume. To grow
legumes successfully requires careful management, as
their requirements are more critical than those of the
commonly grown grasses. The following consideration
will aid in successful legume production:
1. Lime properly pH should be 6.0-7.0 and CaO level
of 900 or above.
2. Fertilize properly Legumes require generous
amounts of P and K. Minor elements will probably be
needed. Soil test results should guide the lime and
fertilizer program, but in the absence of soil test
results the equivalent of about 600 lbs/A of 0-14-14
should be applied at planting with a supplemental
application of 100 lb/A of muriate of potash in the
a) Use specific inoculant
b) Make sure inoculant is fresh
c) Store properly cool, dry
d) Use sticker and/or coating
e) Reinoculate if seed are not planted in 24 hours.
4. Use high quality certified seed (arrowleaf clover
seed should be sacrified).
5. Planting Seed must be in contact with soil and
preferable covered 1/4 3/4 inches deep.
a) Remove excess grass residue graze, mow, burn,
b) Light disking or sod seeder may be used to plant.
c) Plant only when moisture is adequate for germin-
ation between Sept. 15 and Nov. 15.
6. Manage to favor the clover.
a) Don't graze too early
b) Don't overgraze
c) Rotational grazing is preferred.
B. Small grains and/or ryegrass for grazing.
Small grains overseeded into bermudagrass is usually
not ready to graze as early as when planted into a
prepared seedbed. Grazing may not be available until
late December or January on the sod. The use of
ryegrass with the small grain can help maintain high
quality and extend the grazing season.
1. Management considerations
a) Lime and fertilize by soil test results
b) Remove excess grass residue prior to planting
c) Plant only when moisture is adequate
d) Use a seeder which will cover the seed well.
C. Wheat for grain -
Recent work at the North Florida Research and Education
Center at Quincy indicate that wheat may be success-
fully produced by planting into a bermudagrass sod with
a "no-till" drill.
Table 1. Wheat yield as influenced by tillage treatments from
three previous crops (Quincy, 1982).
Tillage Previous Crop Avg. across
Treatment Soybeans Bahiagrass Bermudagrass crops
bottom plow 60.8 a 42.5 a 47.8 a 50.3 a
chisel plow 53.4 a 36.8 a 50.1 a 46.8 a
harrow 48.5 ab 41.4 a 52.0 a 47.3 a
no-till 36.3 b 20.6 b 47.1 a 34.7 b
tillage treatments 49.8 35.3 49.2
*Means in a column followed by different letters are statisti-
cally different at the 5% level of probability.
Following are some considerations when growing wheat for
grain in bermudagrass.
1) Use an early maturing wheat to reduce competition from
the bermuda during grain fill in the spring.
2) Plant as soon after Nov. 15 as possible. This will
also result in earlier maturity of the wheat, allowing
greater production from the bermudagrass.
3) The bermudagrass can make use of any residual fertili-
zer from the wheat, but must be fertilized according to
4) Nitrogen requirements will be greater than on prepared
land. Competition from the grass in early spring
during grain fill has resulted in symptoms of N
deficiency. In the absence of specific recommendations
an additional 40-50 lbs/A of N is suggested.
by 0. Charles Ruelke
We have come a long way since common bermudagrass, Cynodon
dactylon L., was brought to Savannah Georgia in 1751 by Governor
Henry Ellis. As early as 1807 bermudagrass was referred to as one
of the most important grasses in the South.
When southern farmers were trying to grow cotton or corn,
common bermudagrass was a weed pest and some states declared it
was a noxious weed. Yet, its ability to persist and produce
during drought, and heat on sandy soils made it a valuable forage
and cover crop. However, it was not until a hybrid from "Tift"
bermudagrass and an introduction from Africa was developed into
the variety "Coastal" bermudagrass, that farmers had a tall
growing, frost resistant, higher yielding, nematode resistant
variety, which could be used for grazing hay, pellets or other
forms of forage.
Since the development of Coastal bermudagrass, and the
management practices which bring about the best production, there
have been continued efforts to develop new varieties that are
better than Coastal.
Suwannee bermudagrass is a tall growing hybrid developed at
Tifton that will out yield Coastal on lighter sandier soils, but
is less tolerant of close grazing and is less winter hardy.
Midland bermudagrass is a hybrid between Coastal and a cold
hardy common from Indiana. It is more cold hardy than Coastal,
but has not yielded as well as Coastal in Florida.
Coastcross-1, a hybrid between Coastal and a plant from Kenya
was found to be 12% more digestable than Coastal and gave greater
average daily gains in cattle. Coastcross-1 grows taller and
spreads more rapidly and its leaves are softer and broader.
Because of its very limited underground rhizome development it is
less protected from winter injury and therefore, loss of stands
can occur in North Florida.
Alicia bermudagrass was a highly advertised bermudagrass of
the recent past, which has been extensively tested in Florida. It
has been found to be easy to establish and produces early in the
spring. However, total annual yields have been consistently less
than Coastal and digestibilities were significantly lower than
1. Presented at the 6th Annual Fall Forage Forum held November 1,
1984 at the North Florida Research and Education Center, Quincy,
2. Professor of Agronomy, Department of Agronomy of the Institute of
Food and Agricultural Sciences, University of Florida at
Gainesville, Florida 32611.
In Mississippi, a variety was developed called Callie Giant
bermudagrass. This variety has out yielded Coastal in tests in
Florida and has slightly higher digestability at the same age.
HIowever, Callie has been found to be quite susceptable to a rust
disease which has been shown to reduce its digestibility. Callie
is also less winter hardy than Coastal in North Florida.
Efforts are now in progress to improve yield, digestibility
and cold tolerance of the latest bermudagrass hybrids.
Tifton 44 is the best of several thousand hybrids screened
for winter hardiness. Coastal, and a bermudagrass that survived
near Berlin, Germany, for 15 years were used as parents. Compared
to Coastal, Tifton 44 has finer stems, cures faster as hay, has
more rhizomes and starts growth earlier in the spring. Fed to
steers, Tifton 44 gave 19% better average daily gains. In
Florida, it is usually not until the second year that full yield
potential is realized.
Several other unreleased hybrids evaluated in Florida along
with Tifton 44 are Tifton hybrids 72-81 and 72-84. Hybrid 72-81
is a taller and more erect growing bermudagrass which has
consistently produced higher hay yields in Florida than Tifton 44.
Hybrid 72-84 is a short, leafy, dense grass, higher in
digestibility, and it adapts itself better to grazing. Tests
which are in progress at Jay, Florida, indicate that 72-81, 72-84
and Callie bermudagrass could have potential for North Florida.
In April of 1984,a notice of release of Tifton 68
bermudagrass (Cynodon Nlymfuensis Vander) was circulated. This
hybrid lead all entries at all clipping frequencies in % IVDMD.
However, Temperatures of 12 degrees F killed most of the plants.
Although this hybrid may be adapted to the tropics it did not
persist at Gainesville, Florida.
The most recent released hybrid bermudagrass which looks most
promising for North Florida is Tifton Hybrid 78. This is a cross
between Tifton 44 and Callie bermudagrass, incorporating cold
tolerance, higher yield, and higher digestibility than Coastal.
Tests run at Tifton showed a 25.3% greater yield, 7.4% higher
IVDMD, 30% more steer days per acre, 36% more live weight gain per
acre and 13% greater average daily gain from Tifton 78 than from
Coastal. Two releases of planting material to growers who qualify
for certification were made in 1984. Sources of planting material
can be obtained by writing to the Coastal Plain Experiment
Station, P.O. Box 748, Tifton, Georgia, 31793-0748.
Forage production and forage quality evaluation of
bermudagrasses grown in Gainesville, Florida, are shown in Tables
1, 2 & 3. In Table 1, it can be observed that in the 3rd year
after establishment on Arredondo Fine Sand Soils, bermudagrasses
generally out yielded bahiagrasses and digitgrasses. Tifton 44
out yielded Coastal and contained a higher percentage of in vitro
organic matter digested, (IVOMD) and more digested organic matter
(DOM) per acre.
Dry matter yields per acre by harvests shown in Table 2, were
taken the first year following establishment. Tifton 78 and
Hybrid 72-81 appeared to establish very rapidly and produced a
higher 1st cutting yields than Tifton 44 or Coastal, while Tifton
44, Hybrid 72-81 and Tifton 78 produced more total yield than
In Table 3 it can be noted that most of the new hybrids had a
higher % IVOMD than Coastal at the same age and that Tifton 44 and
Tifton 78 produced more #/A DOM than Coastal. Hybrids 72-81 and
35-3 were also superior in the first year of this test.
Coastal bermudagrass has been, and remains a standard
perennial grass which is well suited for hay, grazing, pellets,
and other forms of forage.
Several new and more promising cultivars are becoming
available which produce higher yields or higher digestibility, or
better cold tolerance.
For North and Northwest Florida, on upland well drained
soils, the new varieties Tifton 44 and Tifton 73 look most
promising at the present time.
Table 21 Results of Five Harvests of Forage from Promising New Hybrids and
Cultivars of Perennial Forage grasses Harvested at Gainesville,
Florida in 1980.
Cultivar Evaluated # D.M./A1 % IVOMD2 #/A DOM3
Tifton Hybrid 21-6 bermudagrass
Tifton Hybrid 31-6 bermudagrass
Tifton Hybrid 34-8 bermudagrass
Tifton Hybrid 35-3 bermudagrass
Tifton Hybrid 36-2 bermudagrass
Tifton Hybrid 46-8 bermudagrass
Tifton Hybrid 49-4 bermudagrass
Callie Giant bermudagrass
Tifton 44 bermudagrass
Apomict 54 bahiagrass
Apomict 91 bahiagrass
4th Cycle Pensacola bahiagrass
Established June 10, 1977 on Arredondo Loamy Fine
Gainesville, Florida 32611.
Sand on the Agronomy Farm at
Totals followed by the same letter are not significantly different at the .05
level of significance by the Waller-Duncan test.
All cultivars received 60#/A of nitrogen from a 15-5-10 (N-P20 -K0O) fertilizer
containing 20#T of FTE #503, prior to each of 5 harvests in 19 0 which were
made at approximately after five weeks of growth).
Table 2. Pounds Dry Matter Per Acre of Newest Hybrids and Cultivars
at Gainesville, Florida, in 1983.
of Bermudagrass Harvested
Harvest Number and Date of Harvest in 1983
Tifton 44 bermudagrass
Hybrid 78-22 =Tifton 78
Established on June 3, 1982, on Arredondo Loamy Fine Sand on the Agromomy Farm at Gainesville, Florida, 32611.
All entries received 60 lbs/A of nitrogen
prior to each of five harvests In 1983.
from a 15-5-10 (N-P205-K20) fertilizer containing 20#/T of FTE #503,
1. 6th cut in November 1983 omitted due to uneven damage from Striped Grass Loopers.
Table 3 Results of Five Harvests of the Newest Hybrids and Cultivars of Bermuda-
grass Harvested at Gainesville, Florida in 1983.
Entry Evaluated #D.M./A % IVOMD #/A DOM
Coastal bermudagrass 9,027 54.02 4,876
Tifton 44 bermudagrass 13,945 52.22 7,279
Hybrid 78-22=Tifton 78 11,026 55.47 6,116
Hybrid 79-6 9,188 59.95 5,049
Hybrid 79-9 9,615 56.77 5,458
Hybrid 79-13 8.329 56.95 4,743
Hybrid 79-16 7,408 55.22 4,090
Hybrid 79-17 7,290 56.60 4,126
Hybrid 80-2 6,519 56.22 3,664
Hybrid 80-5 7,153 60.55 4,331
Hybrid 80-10 7,392 57.12 4,222
Hybrid 80-12 5,429 55.20 2,996
Hybrid 35-3 11,233 53.72 6,034
Hybrid 72-81 12,451 53.47 6,658
Established on June 3, 1982, on Arredondo Loamy Fine Sand on the Agronomy Farm at
Gainesville, Florida 32611.
All entries received 60 Ibs/A of nitrogen from a 15-5-10 (N-P205-K20) fertilizer c
ing 20#/T of FTE #503, prior to each of 5 harvests in 1983.
6th Harvest in November 1983 was omitted due to uneven damage from Striped Grass Lo-
Hay Standards and Infrared Evaluation of Bermudagrass
John E. Moore
Professor of Animal Science
University of Florida, Gainesville, 32611
Since January, 1982, a Forage Testing Program has been under development
for Florida. The program centers around Near-Infrared Reflectance (NIR)
analysis conducted at the Ona Agricultural Research Center. Samples are
submitted through County Extension offices. Results of NIR analysis are being
returned in about five days. Reports include Crude Protein (CP), Total
Digestible Nutrients (TDN) and Quality Index (QI). Quality Index was
developed for this program as an overall measure of forage nutritional value.
It is an estimate of the voluntary intake of TDN when the forage is fed alone
The objective of this discussion is to describe Hay Standards based on QI
and to review estimates of bermudagrass quality obtained by NIR analysis of
samples submitted to the Forage Testing Program.
Table 1 shows shows the expected relationship between QI and animal
performance. The QI is voluntary intake of TDN expressed as a multiple of the
maintenance TDN requirement. If QI equals 1.0, animals would be expected to
only maintain themselves. However, a lactating cow could not maintain weight
on hay having a QI of 1.0 because she would have to mobilize body tissue for
Table 1. Relationship Between Forage Quality Index and Expected Performance
by Heifers and Cows
Expected Performance <1.0 1.0 1.4 1.8 2.2
Heifer Weight Change, lb/day loss 0 0.6 1.3 1.9
Cow Milk Production, lb/day 0b 0b 10b 20b 30b
aVoluntary intake of TDN as a multiple of the maintenance TDN requirement
(a QI of 1.0 = maintenance).
bLactating cows producing more milk than expected will suffer weight loss
Table 2 shows the results of a series of our studies on the quality of
summer perennial grasses. These hays were harvested after various regrowth
intervals following an initial harvest in June. At two weeks regrowth,
bermudagrass QI was about 1.4 which would support about 0.6 lb/day gain by
heifers (Table 1). After eight weeks regrowth, bermudagrass would only
maintain weight of cattle unless supplements were fed. Digitgrasses tended to
have slightly higher quality than bermudagrasses and bahiagrasses at given
stages of maturity. Table 3 shows that the season of harvest may be just as
important as stage of maturity in determining quality of bermudagrass. Even
when cut at regular regrowth intervals throughout the season, quality tended
to decline as the season advanced.
Table 2. Effect of Species and Maturity upon Quality Index, Total Digestible
Nutrients (TDN) and Crude Protein (CP) of Florida Grassesa
Weeks of Quality
Species Regrowth Indexb TDNc CPc
Bermudagrass 2 1.38(2)d 56.3(2) 16.0(2)
4 1.34(9) 57.1(9) 13.6(9)
6 1.21(7) 52.6(7) 9.0(7)
8 1.00(7) 47.9(7) 7.5(7)
10 0.92(4) 46.1(5) 8.3(5)
Bahiagrass 2 1.33(7) 58.6(10) 11.6(10)
4 1.17(10) 55.8(12) 9.8(12)
6 1.20(8) 55.4(9) 8.5(9)
8 1.09(7) 54.4(3) 7.5(7)
10 0.75(3) 46.8(4) 6.9(4)
Digitgrass 2 1.51(11) 60.4(11) 13.4(11)
4 1.48(16) 59.4(16) 12.6(16)
6 1.25(13) 57.8(14) 8.9(14)
8 1.10(13) 55.1(13) 6.6(13)
10 0.78(3) 49.7(4) 6.5(4)
aData summarized from several exp
bVoluntary intake of TDN as a mul
cPercent of dry matter.
dAverage (number of experiments).
eriments, University of Florida.
tiple of maintenance.
Table 3. Quality of Coastal Bermudagrass Hay Harvested at Different
Maturities and Seasonsa
Weeks of Harvest Date
Item Regrowth 6/14 7/12 8/9 9/6 10/4
TDN, %b 4 54.6 56.9 52.0 52.7 45.8
6 51.6 50.7 46.9 49.4 48.4
8 52.2 51.2 45.9 46.8 43.6
Quality Indexc 4 1.38 1.35 1.28 1.34 1.12
6 1.32 1.37 1.02 1.19 1.21
8 1.32 1.09 0.85 1.06 0.75
ADG, lbd 4 0.57 0.78 0.72 0.63 0.28
6 0.34 0.48 -.04 0.42 0.22
8 0.16 0.07 -.39 0.07 -.39
aAdapted from Nelson, et al., Louisiana Agr. Exp. Sta. Bull. 730,
bTDN = Total Digestible Nutrients, % of dry matter.
cVoluntary intake of TDN as a multiple of maintenance.
dADG = Average Daily Gain, in pounds (feeding trial conducted December
It is not intended that Hay Standards be used to set the price of hay,
but results of forage testing should be useful in negotiations of price
between buyer and seller. High quality forage is more expensive to produce
but should be worth more if it gives higher animal production with less need
for purchased supplement. A forage test may be used along with other
information, experience and good judgement in making management decisions
regarding nutritional needs of the beef herd. If the forage is inadequate to
meet management objectives, then a supplementation program may be developed.
Table 4 shows calculations of the supplemental CP and TDN required for
different classes of beef cattle consuming different qualities of hay. For
example, if a cow producing 15 lb of milk was fed hay having a QI of 1.2,
supplements should provide 0.7 Ib of CP and 2.5 lb of TDN in order to prevent
Table 4. Estimated Need for Supplemental TDN and Crude Protein (CP) For
Cattle Fed Different Quality Foragesa
Animal: Pregnant Cow Lactating Cowb Growing Heifer
Weight, Ib: 1000 1000 500
Production, lb/day: .9 gain 15 milk 1.0 cain
Supplement Needed: CP TDN CP TDN CP TDN
QIc TDN,% CP,%
.9 43-52 4- 9 .25 2.2 1.4 5.5 .7 4.2
1.2 51-58 5-12 .7 2.5 .4 2.0
1.5 56-64 7-20 -
aKunkle, Proc. Florida Beef Cattle Short Course, 1984. pp 77-85.
bCows maintaining weight.
cPounds per head per day of Crude Protein (CP) or Total Digestible
Nutrients (TDN). TDN must be supplied with high energy feeds such as
grain or molasses.
cI = Quality Index (voluntary intake of TDN as a multiple of
Table 5 shows the results of NIR analyses of grass samples submitted
to the Pilot Program. Most of the hays had QI values of 1.0 to 1.2. Many
of the hays, even those with the higher QI values, had low protein (less
than 7%) suggesting the need for supplemental protein. Values for QI and
CP should be considered separately since within a given QI there is a wide
range in CP values. Even if QI values are above 1.0, supplemental protein
may be needed if the level of CP is below the requirement. Bermudagrass
(including some stargrass) samples submitted had a wide range in QI from
the lowest (0.8) to the highest (1.5). These data are similar to those
obtained on research hays cut at advanced maturity (Table 2) or late in the
season (Table 3).
Table 5. Ranges in Near Infrared Reflectance Estimates of Quality Index,
Crude Protein and Total Digestible Nutrients (TDN) in Hays from
the Florida Forage Testing Program
Coiposition. % of Dry Matter
Indexa No. Crude Protein TDN
0.8 1 6.6 41.8
0.9 13 1.7 8.2 41.2 47.5
1.0 35 2.7 9.5 45.1 50.7
1.1 68 2.3 11.4 47.5 55.1
1.2 40 2.8 12.9 50.6 57.4
1.3 15 3.0 16.0 56.0 58.2
1.4 8 9.4 13.2 57.0 62.2
1.5 3 12.2 23.3 63.8 64.8
0.8 1 6.6 41.8
0.9 6 3.9 8.2 42.7 47.5
1.0 26 3.5 9.5 45.8 50.7
1.1 34 4.6 11.4 49.7 55.1
1.2 24 4.9 12.9 50.6 57.4
1.3 11 9.3 16.0 56.0 58.2
1.4 6 9.4 13.2 57.0 60.8
1.5 3 12.2 23.3 63.8 64.8
0.9 3 1.7 5.0 42.0 44.9
1.0 4 3.5 7.0 46.3 48.8
1.1 17 3.9 8.1 47.5 52.5
1.2 4 8.2 9.6 54.3 55.2
1.3 0 -
1.4 1 12.8 62.2
1.0 2 4.6 6.2 46.1 46.1
1.1 15 2.3 7.2 47.6 52.5
1.2 10 2.8 10.6 52.3 55.1
1.3 3 5.5 10.2 56.4 57.6
0.9 4 2.0 3.6 41.2 44.2
1.0 3 2.7 8.8 45.1 48.3
1.1 2 2.9 9.1 49.5 51.7
1.2 2 8.6 10.5 52.0 52.6
1.3 1 2.9 58.2
1.4 1 9.5 59.0
voluntary intake of TDN as a multiple of maintenance.
Summary and Conclusions:
Hay standards have been developed for Florida which are related to animal
performance. Quality Index is an estimate of the voluntary intake of Total
Digestible Nutrients when the hay is fed alone and free-choice. There is a
close relationship between Quality Index and expected animal performance. An
Extension Forage Testing Program has been initiated which utilizes
Near-Infrared Reflectance analysis to provide results which include Quality
Index, Total Digestible Nutrients and Crude Protein. Information from the
test may be used to negotiate hay price and to formulate a supplementation
It is possible to have bermudagrass hay of relatively high quality, but
most hays submitted to the Forage Testing Program were of low to medium
quality. The reasons for the lower quality of many of these hays are (1) the
species are tropical grasses which have low inherent quality and which mature
rapidly, (2) the effects of the hot, humid environment are to decrease
quality, and (3) harvest is often delayed due to frequent summer rains. The
wide range in quality of Florida summer perennial grass hays demonstrates the
need for testing of each cutting if quality information is important in the
livestock management plan.
Irproving Low Quality Hay With Ammonia
William E. Kunkle
Extension Beef Specialist
Department of Animal Science
University of Florida
Many ranchers in Florida feed hay to their cattle during the winter
months when pasture is not available. Much of the hay is harvested after
the summer rainy months and is low in digestible nutrients (TDN) and pro-
tein. Supplemental energy and protein are often required for acceptable
performance of beef cattle, especially cows with calves and growing heif-
ers. Anhydrous armmnia treatment of low quality hay and crop residues is
an effective and economical method of increasing the crude protein, TDN
and consumption of these low quality feeds.
The treatment of low quality forages with anhydrous ammonia was first
investigated by European and Canadian researchers. Since the late 70's
considerable research has been conducted in the United States. This
report will summarize results from Florida research and give pertinent
information from research across the United States.
Procedures for Treating Hay
Type of Hay. Most of the research has been conducted on mature grass hay
or crop residues. These require supplements in most feeding programs and
have the most potential for improvement. A few examples are mature grass
hays (over 8 weeks between cuttings), bahia grass hay cut after seed pro-
duction, corn stalks, wheat and other straws, etc.
Level of Amnonia. Research trials have shown good results when 2.5 to
2.7% anhydrous amionia was applied to the hay. A 1000 lb. round bale
would require 25 to 27 lb of anhydrous ammonia. Lower levels of aamonia
were not as effective in increasing digestibility of the hay.
Length of Treatment. The time required to obtain increased feeding value
is dependent on temperature. During warm weather (over 70F average) two
weeks should be sufficient but during cool weather four to six weeks has
shown better results. The hay can be treated for periods longer than
needed with no problems. The hay pile can be kept covered until it is
Treatment Method. A few bales of hay should be weighed to determine the
aiiount of ammonia needed. The bales need to be stacked in a pile and
covered with polyethylene prior to releasing anmonia. The bales can be
stacked with two on the ground and one placed in the groove to help shed
rain off the plastic. (Example: 8 ). A pile of bales
with 15 bales end to end in the above configuration will contain 45 bales
and can be covered with a 28'x 100' piece of plastic. Many people have
used six mil polyethylene (clear or black) that is available at many
construction suppliers. The anhydrous ammonia is a liquid until vol-
atilization; therefore, a container such as a clean steel drum is needed
to hold the liquid. This will require a 55-gallon drum with open top or
equivalent for each ten bales. The drums are placed around the stack of
rolls and 6' to 10' of 3/4' black plastic pipe is secured into each drum.
The pile is covered with polyethylene and dirt is used along the edges to
pull the polyethylene tight and make a seal with the ground to prevent
escape of ammonia. Polyethylene is not needed on the ground under the
stack. The plastic pipe from each drum is left exposed under the plastic
for connecting the ammonia tank. The hose from the anhydrous tank can
have the hand tightened adapter removed and with pipe fittings reduced to
a 1/2" pipe that can be attached to the 3/4" plastic pipe and secured with
a clamp. The anhydrous ammonia is allowed to flow slowly into each drum
and the amount is determined accurately with a metering device or estimat-
ed with the percentage full gauge. The anhydrous ammonia will volatilize
in two to seven days depending on the temperature. It is imperative that
the polyethylene is well sealed prior to adding awmonia. Punctures or
tears in the polyethylene can be repaired with duct or plastic tape. The
hay should be treated with anhydrous ammonia soon after covering with
polyethylene to prevent molding caused by condensation.
Safety. Anhydrous ammonia is a caustic and potent chemical. It readily
seeks water and will volatilize and spread very rapidly. The 3/4" plastic
pipe system to convey anhydrous armonia into the drums should have open
ends to prevent a build-up of pressure. An operator should make absolute-
ly sure all connections are tight prior to releasing the arimonia. The
tank, valves, regulators and hoses should be properly maintained. The
applicator should wear goggles, rubber gloves and protective clothing when
handling ammonia. Fresh water should be kept nearby for cleansing the
skin or eyes in case of an accident. Always be aware of prevailing winds
and position the equipment accordingly.
Benefits of Aimonia Treatment
Crude Protein. The crude protein content of low quality grass hays is
often below 6% and anhydrous animonia treatment will increase the crude
protein above 12% in rost situations. Three trials with bermuda grass hay
resulted in crude protein levels from 12.7% to 14.1% after anhydrous
anrmonia treatment (Table 1).
Table 1. EFFECT OF AI1MONIA TREAfTENT ON THE CRUDE PROTEIN COICENT
AiD DIGESTIBILITY OF HAY
Bermuda Grass Bermuda
Trial 1a Trial 2,4 and Bahiaa
Level of Ammonia,
% dry matter 3.0 2.8 2.6
Crude Protein, %c
Untreated 5.5 7.5 4.2
Armmonia 12.9 14.1 12.7
In Vitro Organic Matter
Untreated 40.0 40.5 42.2
Ammonia 50.9 57.2 53.3
aReference: 1983 Florida Beef Cattle Research Report, p. 107.
bReference: 1984 Florida Beef Cattle Research Report, p. 64.
cAverage level in dry matter.
A summary of 24 trials from 8 states showed the crude protein of wheat
straw increased from 3.6 to 8.9%, corn residue increased from 5.9 to
12.0%, milo residue increased from 7.0 to 15.8% and soybean straw from 6.0
to 12.5%. Forages with higher moisture levels tend to retain more of the
ammonia and have larger increases in their crude protein. However, crude
protein levels above 10% may be higher than can be efficiently utilized in
many feeding situations because the level of digestible energy limits the
amount on non-protein nitrogen that is utilized.
Digestibility. The digestibility of low quality forages is increased 6 to
15 percentage units after treatment with anhydrous ammonia. Three trials
with bernudagrass hay showed the digestibility increased 10.9 to 16.7
percentage units after treatment with anhydrous anmonia (Table 1). A
summary of trials from 10 states showed the digestibility of wheat straw
increased 10.4 percentage units, corn residue increased 8.3 percentage
units, milo residue increased 15 percentage units and soybean straw
increased 6 percentage units after ammonia treatment.
Consumption and Wasteage. The rate of digestion is increased which allows
the cattle to consume more of the low quality forage. A summary of 14
trials from several states showed a 22% increase in forage consumed with a
range from 9 to 39% increase in consumption. A reduction in wasted hay
has also been noted after ammonia treatment. Cattle will consume weath-
ered hay on the outside of the bales much more readily than prior to treat-
ment. In some feeding trials estimated losses due to wasted hay have been
reduced to 10% or below. The increased consumption can be offset in part
by a reduction in wasted hay. Two trials (Tables 2 and 3) with Bermuda-
grass hay in Florida have resulted in a 10.1 and 5.7% increase in hay
offered to the cattle but the actual consumption was probably increased
even more because wasted hay was not accurately quantitated.
Cattle Performance. The increases in consumption and digestibility result
in rore TDN intake and better performance of the cattle. Beef cows receiv-
ing ammonia treated hay and supplement consumed less supplement and lost
66 lb less weight during the calving period (Table 2). In fact beef cows
fed only ariionia treated hay lost less weight (35 lb) and had similar
pregnancy rates, calving intervals and calf weaning weights compared to
cows fed untreated hay and 4.4 lb/day of a 16% liquid supplement. In
another trial (Table 3) lactating beef cows fed amronia treated nay had
similar weight losses during the trial but shorter calving intervals and
heavier calf weaning weights than beef cows fed untreated hay and a
similar supplement. The protein supplied in the anmionia treated hay
appeared to be utilized nearly as good as cottonseed meal in this trial
where corn and molasses supplements were also provided. A summary of
eight trials with gestating beef cows from other states showed a .67
lb/day better per-formance for anmonia treated crop residues compared to
untreated residues. A summary of seven trials with growing calves showed
a .26 lb/day increase in gain for calves fed anmonia treated hays and crop
residues compared to untreated crop residues.
Costs and Returns
Costs. The costs of treating a stack of 45 large round bales and a ton of
hay are outlined as follows:
Cost of Treatment
Cost/Unit 45 Rolls Ton
Anhydrous anmonia (25 lb/roll) $300/ton $170 $ 7.60
Polyethylene (6 mil x 28' x 100') $ 70 each $ 70 $ 3.10
Labor (12 hrs/stack) $ 4/hr $ 48 $ 2.10
Returns. An estimation of the level of supplemental corn and urea needed
to provide a nutrition level equal to ammonia treated hay was calculated.
Amrmonia treatment of low quality hay was assumed to increase consumption
20%, increase hay offered by 10% (part of increased consumption from
reduced wasteage), and increase digestibility by 8 percentage units (42%
to 50%). The calculations are as follows:
Untreated Hay Ammonia Treated Hay
Hay offered, lb/day 20 22
Fraction consumed .8 .9
Hay consumed, lb/day 16 19.8
Digestibility .42 .50
TDN consumed, lb/day 6.7 9.9
Difference, lb/day -- 3.2
The extra 3.2 lb of TDN and .8 lb crude protein consumed by beef cows
consuming ammonia treated hay can be supplied by 4 lb of corn and .2 lb of
urea. The daily costs are as follows:
Untreated Hay Ammonia Treated Hay
Hay ($50/ton) 20 lb x $.025/1b=.50 22 lb x$.025/lb =.55
NH3Treatment ($12.80/ton) 22 lb x$.0064/lb =.14
Corn ($140/ton) 4 lb x $.07/lb =.28 -
Urea ($300/ton) .2 lb x $.15/lb =.03 -
Total Cost, $/day .81 $.69
In this example, an investment of $.19/day in ammonia and extra hay
provided nutrition equal to $.31/day from corn and urea. Ammonia
treatment cost only 61% as much as a comparable level of supplement from
corn and urea.
The ammonia added to the hay is non-protein nitrogen and requires
several minerals to be present for efficient utilization. Sulfur is
required by bacteria before the ammonia can be synthesized into protein
and is routinely added to commercial supplements containing non-protein
nitrogen. Sulfur is present in mineral supplements but only at trace
amounts. A good source of sulfur is potassium and magnesium sulfate
(Dynamate) and 1.25 ounces/hd/day mixed in the mineral or a grain should
provide adequate sulfur. Low quality hays are often very deficient in
phosphorus especially for lactating beef cows. In many cases 4-6
ounces/day of a mineral supplement containing 8% phosphorus may be
required to correct the deficiency in the lactating beef cow.
Amronia treatment of some types of forages has resulted in the death
of cattle in a few cases. Most of these cases have involved grain sorghum
residue or wheat cut for hay. The cattle have exhibited very aggressive
behavior and have been reported to run through fences, corrals, side of
barns, etc. The cattle become unpredictable in behavior and are
dangerous. Several cattle deaths have resulted from self inflicted in-
juries. The compound suspected of causing the problem is 4-methyl-
imidazole. This compound is formed when ammonia reacts with sugars. The
situations where problems have developed involved higher quality forages
that contain sugars. Levels of aunonia above the recommended level of 3%
may have been used in some cases. I am not aware of any problems in
Florida and problems are not expected if low quality forages are treated
at recoriended levels.
TABLE 2. EFFECTSS OF AtlOMNI;, TF.EArT:E:;T OF 5EF:UD..GFASS HAY AND
SUPPLEMENTAL FEED ON THE PERFORMANCE OF BEEF COWSa
Untreated Hay Hay 3% ;flnonia
16% Liquid 16% Liquid No
Supplement Supplement Supplement
No. Of Cows 20 20 19
lb/cow/day 19.1 22.0 22.0
Ib/cow/day 4.4 3.1 --
Cow Weight Change, lb (113 days)
Open Cows +7 ( 6) +11 ( 6) +25 ( 6)
Cows with Calvesc -248 (14) -182 (14) -213 (13)
Cows Pregnant, %d 90 90 100
Calving Internal, days
(Cows with Calves) 372 (12) 366 (11) 376 (11)
Calf, 205 Day Wean Wt.,
lb. 433 (12) 420 (13) 425 (12)
alpine Acres Research Farm, University of Florida, 1983 Florida Beef Cattle
Research Report, p. 107.
Hay offered to cows, 5-10% of hay not consumed.
CAngus cows calved in October and November, includes weight loss of calving
(No. of cows), Initial Weight was 1104 lb.
dExperiment ended at beginning of breeding season and cows gained weight
during 70 day breeding season.
TABLE 3. EFFECTS OF ANHYDROUS AMMONIA TREATMENT OF BERMUDAGRASS HAY AND
A COTTONSEED MEAL SUPPLEMENT ON THE PERFORMANCE OF LACTATING
Untreated Hayb Ammonia Hay Ammonia Hay
Item Cottonseed Cottonseed Corn
No. of Cows
Hay Offered, lb/cow/day
Initial Cow Weight, lb
Cow Daily Gain, lb
11/29 to 3/22 (113 days)
3/22 to 6/6 (78 days)
Cow Condition Change
11/29 to 3/22
3/22 to 6/6
+.13 + .19
-.39 1 .17
-.31 + .15
-.35 + .11
Calving Interval, days
205 Wean Weight, lbe
377 + 4c
403 + 23C
444 18 'd
alpine Acres Research Farm, University of Florida, 1984 Florida Beef Cattle
Research Report, p. 64.
Anhydrous ammonia applied at 2.8% of hay dry matter, cottonseed meal based
supplement (23% crude protein) fed at 3.8 lb/cow/day, corn based supplement
(8 % crude protein) fed at rate of 3.6 lb/cow/day.
c,dMeans with different superscripts all significantly different (P(.05)