• TABLE OF CONTENTS
HIDE
 Front Cover
 Front Matter
 Table of Contents
 Main
 Literature cited
 Back Cover














Group Title: Bulletin - Florida Agricultural Experiment Station. University of Florida ; 888
Title: Improving the feeding value of hay by anhydrous ammonia treatment
CITATION THUMBNAILS PAGE IMAGE ZOOMABLE
Full Citation
STANDARD VIEW MARC VIEW
Permanent Link: http://ufdc.ufl.edu/UF00086514/00001
 Material Information
Title: Improving the feeding value of hay by anhydrous ammonia treatment
Series Title: Bulletin
Physical Description: 10 p. : ill. ; 28 cm.
Language: English
Creator: Brown, W. F
Kunkle, William, 1947-
Publisher: Florida Agricultural Experiment Station, Institute of Food and Agricultural Sciences, University of Florida
Place of Publication: Gainesville
Publication Date: 1992
 Subjects
Subject: Hay as feed   ( lcsh )
Ammonia   ( lcsh )
Genre: government publication (state, provincial, terriorial, dependent)   ( marcgt )
bibliography   ( marcgt )
non-fiction   ( marcgt )
 Notes
Bibliography: Includes bibliographical references (p. 10).
Statement of Responsibility: W.F. Brown and W.E. Kunkle.
General Note: Cover title.
General Note: "May 1992."
Funding: Bulletin (University of Florida. Agricultural Experiment Station) ;
 Record Information
Bibliographic ID: UF00086514
Volume ID: VID00001
Source Institution: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: oclc - 26241622

Table of Contents
    Front Cover
        Front Cover
    Front Matter
        Front Matter
    Table of Contents
        Table of Contents
    Main
        Page 1
        Page 2
        Page 3
        Page 4
        Page 5
        Page 6
        Page 7
        Page 8
        Page 9
    Literature cited
        Page 10
    Back Cover
        Back Cover
Full Text

May 1992


Bulletin 888


Improving

the Feeding Value

of Hay by Anhydrous

Ammonia Treatment





W. F. Brown and W. E. Kunkle


.^ r', .
. i


Florida Agricultural Experiment Station
Institute of Food and Agricultural Sciences
University of Florida, Gainesville
J. M. Davidson, Dean for Research


100
F636b
888





















Hay Ammoniation


Procedures are not complicated or costly
(costs approximately $15.00 per ton)

Ammoniation improves hay feeding value:

increases protein concentration of hay
increases digestibility of hay
increases intake and daily gain by cattle

Ammoniated hay plus an energy/natural protein
supplement such as molasses-cottonseed meal can
provide the nutrition necessary to develop a heifer
for breeding as a yearling.

/1
F i





atw,'c


Dr. W. F. Brown is an Associate Professor of Animal Science at the Agricultural Research and Education Center-Ona, Ona, Florida 33865; Dr.
W. E. Kunkle is an Associate Professor in the Animal Science Department, University of Florida, Gainesville, Florida 32611.















Contents
Introduction ................. ... ................... 1
Purpose ............................................ 1
Procedures for treating hay with anhydrous ammonia ........... 1
Anhydrous ammonia treatment level .......................3
Costs of ammoniating hay ................................. 4
Non-nutritional benefits of ammoniated hay .................. 4
Nutritional benefits of ammoniated hay ......................4
Forage maturity and ammoniation ......................... 6
Supplementation or ammoniation ................... ........7
Feeding programs including ammoniated hay ..................8
Precautions for the use of ammoniated hay ................ ...9
Recommendations ........................................9
Literature cited .......................................... 10
Selected publications concerning ammoniated hay ............ 10








Introduction
During the winter, many Florida
cattle producers graze replacement
heifers on bahiagrass or other tropi-
cal grass pasture and feed low-qual-
ity hay and an energy-protein
supplement such as molasses-urea.
Historically, this feeding program
has not provided the nutrition nec-
essary for developing heifers so they
can be bred as yearlings. In a sum-
mary of beef-forage practices in
south central Florida (Beef-Forage
Practices, 1986) and southwest
Florida (Beef-Forage-Range Prac-
tices, 1990), approximately 50% of
livestock producers surveyed indi-
cated that nutrition was the most
serious problem limiting reproduc-
tion in beef cattle. Approximately
50% of producers indicated that
heifers calved their first time at
three years of age or older. A pri-
mary reason more Florida cattle
producers do not attempt to breed
heifers as yearlings is low quantity
and/or quality of forage (stockpiled
pasture, hay) available for the
heifer during the first winter follow-
ing weaning. Also, a greater level of
feeding is required for a two-year-
old, first-calf heifer so she will
rebreed to calve at three years of
age, as compared to calving for the
first time at three years of age.

Approximately 750,000 acres of
permanent, improved grassland are
used for hay production in Florida
each year, with an average hay
yield of 5,000 lbs/acre. Most of this
hay is low quality because more em-
phasis is placed on yield than qual-
ity. In the summary of beef-forage
practices in south central Florida
(Beef-Forage Practices, 1986), 81%
of livestock producers indicated
they used hay, however only 10% of
producers had the hay tested for
quality. Results from the Univer-
sity of Florida Extension Forage
Testing Program (Brown et al.,
1990) indicated that the average
crude protein (CP) concentration of


Florida-grown hay was 7%, and the
average total digestible nutrient
(TDN) concentration was 43%.
Yearling heifers require a diet that
is 11 to 12% CP and 60 to 65%
TDN. Low-quality hay plus an en-
ergy-protein supplement such as
molasses-urea may not provide the
nutrients necessary to develop a
heifer during her first winter after
weaning so that she will be ready to
breed as a yearling.

Improved hay quality can be ob-
tained by harvesting a less mature
forage. However, many cattle pro-
ducers will not sacrifice extra yield
to obtain better quality hay, and in
many cases weather conditions are
not favorable for hay making at the
optimal harvest time. In these
cases, large quantities of low-qual-
ity forage accumulate. Chemicals
such as sodium or calcium hydrox-
ide and ammonia have been used to
improve the feeding value of low-
quality forages. Increasing interest
in ammoniation of hay has devel-
oped due to ease of treatment, low
cost, and the ability to treat large
quantities of hay at once.

Purpose
The purpose of this bulletin is to
describe how anhydrous ammonia
can be used to improve the feeding
value of tropical grass hay. Topics
discussed include procedures for
treating hay with ammonia, the
proper concentration of ammonia to
use, costs, feeding programs and
precautions for ammonia use.

Procedures for treating
hay with anhydrous
ammonia
An important aspect of hay am-
moniation is that there are no com-
plicated procedures to follow. The
procedure is simple, not too costly,
and can be accomplished with lo-
cally-available materials. There are
many variations on procedures used


for ammoniation, depending upon
available equipment. The only re-
quirement is that the hay and am-
monia be enclosed in a "container"
for about a month before feeding.
This "container" is usually a sheet
of black plastic used to cover the
hay with the edges sealed in the
ground to enclose the hay stack
with an air-tight seal.

The hay stack should be ar-
ranged to minimize costs of materi-
als and labor for each specific situa-
tion, and still provide proper condi-
tions for ammoniation. Arrange-
ment of hay bales on the ground de-
pends upon equipment available,
size of plastic available and the
number of bales to be treated.
Some producers have front-end
loaders that can stack large round
hay bales in a 3-2-1 pyramid con-
figuration, while other loaders can
stack in a 2-1 pyramid. Other pro-
ducers have a spike on the rear of
the tractor to move round bales, and
can not stack hay. Other producers
have square bales. Hay in all these
situations can be ammoniated.

An example of how hay is stacked
for ammoniation at the Agricultural
Research and Education Center-
Ona using round bales in a 3-2-1
pyramid is shown in Figure 1. As
the hay bales are stacked, a small
space (2 to 3 inches) is left between
cut edges of adjacent bales so that
ammonia can circulate within the
stack. Note how bales in the middle
layer overlap those on the bottom,
and bales on the top overlap those
in the middle.

About mid-way down the length
of the stack, an approximate two-
foot-wide space is left on the bottom
layer of bales (Figure 2). A PVC
pipe (discussed below), which aids
in delivery of ammonia from the
tank to the stack, is placed into this
opening. Round bales shown in Fig-
ure 1 are five feet in diameter, and



























Figure 1. Nontreated hay stacked and ready for ammoniation.


(Figure 3). One-quarter to one-half
inch diameter holes are drilled
along a line beginning at the capped
end and continuing for 10 to 12 feet.
The pipe is positioned in the stack
so that the drilled holes are point-
ing upwards. The open end of the
pipe is positioned towards the out-
side of the stack, and is attached to
the hose that comes from the am-
monia tank. Use of the pipe is not
essential, but it helps to distribute


Figure 2. Opening in the bottom layer of
bales (approximately mid-way
down the length of the stack) for
delivery of ammonia.
weigh approximately 1000 lbs.
These bales can be arranged with
15 rows of three bales on the bot-
tom, 14 rows of two bales in the
middle and 13 rows of one bale on
the top, for a total of 86 bales. A 40-
foot X 100-foot sheet of 6-mil-thick-
ness black plastic will cover this
arrangement.

The PVC pipe used to deliver am-
monia from the tank to the stack is
2 inches in diameter, approximately
20 feet long and capped on one end


ammonia more uniformly within
the stack.

A small trench (1 to 2 feet deep)
is dug around the stack to secure
the plastic. Some producers own a
ditcher, or one can be rented. Five
to eight hay stacks can be ditched
with a half-day rental of a ditcher.
A back-blade positioned at an angle
on the back of a tractor also works
well. The plastic is placed over the
stack, and the edges placed into the
trench and covered with soil to seal
the stack (Figure 4). Black plastic
of at least 6-mil thickness should be
used. Clear plastic that does not
contain an ultra-violet inhibitor
should not be used because it be-
comes very brittle in a short period
due to exposure to the sun. More
durable plastics containing an ul-
tra-violet inhibitor or nylon rein-
forcement can be used; however,
these products are expensive and
will have to be reused for several
years to be cost effective. After the
plastic is placed over the hay stack
and sealed into the trench, it should
be checked for holes such as those
caused by hay stems puncturing the
plastic during covering. Holes in
the plastic can be sealed with duct
tape.


The hose from the ammonia tank
is then connected to the PVC pipe,
or placed under the plastic if no
.pipe is used (Figure 5). Anhydrous
S. -jq ammonia tanks have a capacity
-.,f,. ; q gauge to meter the proper quantity

nia leaves the tank as a liquid and
r then turns into a gas and fills the
area under the plastic. Depending
upon how fast the ammonia is
iito allowed to flow into the stack, the
: plastic can balloon out and become
: very tight. About five hours are re-
quired to apply the proper amount
of ammonia to the stack. When
ammonia is being applied, the stack
should be checked about every
Figure 3. PVC pipe which will be placed hour to make sure the process is
into the opening in the hay stack proceeding normally.
shown in Figure 2. proceeding normally.





























Figure 4. Hay stack being covered with a 40- by 100-foot sheet of 6-mil-thickness black
plastic. Note trench around stack.


Figure 5. Anhydrous ammonia tank delivering ammonia to the stack through the hose
attached to the PVC pipe shown in Figure 3.


After 1 to 2 days, the ammonia
will be absorbed into the hay. Treat-
ment time depends upon environ-
mental temperature; the warmer
the temperature the faster the reac-
tion time. As a general rule, hay
should remain sealed under the
plastic for about 30 days before
feeding. When the hay is ready to
feed, the plastic can be cut at


ground level to expose only the
number of bales to be removed from
the stack. Plastic remains over the
rest of the hay to help keep it dry.

Anhydrous ammonia is a caustic
chemical and can be dangerous if
not used properly. Tanks contain-
ing ammonia are under pressure,
and all connections should be


checked before releasing ammonia
from the tank. Ammonia will burn
the skin and eyes, so fresh water
should be available to wash off any
ammonia that contacts the skin.
Always remain upwind of the hay
stack when applying ammonia.
Ammonia is very corrosive to most
metals.

Anhydrous ammonia
treatment level
Tropical grass hays such as
bahiagrass, bermudagrass,
digitgrass, limpograss and
stargrass should be treated with
anhydrous ammonia at the rate of
4% of the forage dry matter. To de-
termine the amount of ammonia
needed to treat a stack of hay, mul-
tiply the number of bales in the
stack, times the weight of each bale,
times the percentage dry matter of
the hay, times 0.04. Bale weight
and hay dry matter percentage usu-
ally will be estimates. Four-foot-di-
ameter bales are typically 800 lbs,
and five-foot-diameter bales are
typically 1000 lbs. Hay that is
dried properly is typically 85% dry
matter. For the example above,
there were 86 bales, each bale
weighed approximately 1000 lbs,
and hay dry matter percentage was
approximately 85%. The amount of
ammonia needed is: 86 x 1000 x
0.85 x 0.04 = 2924 lbs.

The capacity gauge on the ammo-
nia tank can be used to meter the
proper amount of ammonia into the
stack. Our tank at the AREC-Ona
has a maximum capacity of 5000 lbs
of ammonia. Tanks are typically
filled to only 90% of capacity to al-
low for expansion of the ammonia
as the environmental temperature
increases. This equals 4500 lbs of
ammonia when the tank is 90% full.
In the above example, 2924 lbs of
ammonia are required, and with a
tank that initially is 90% full (4500
lbs ammonia) there should be 1576
lbs of ammonia (4500 2924) in the








tank when finished. When finished,
the capacity gauge should read
approximately 30% (1576 X 90 =
141840 / 4500 = 31.5).

Costs of ammoniating
hay
The key is to minimize costs of
materials and labor for each ton of
hay in each specific situation. In
the above example, there were 86
round bales, each bale weighed
1000 lbs, 2924 lbs of ammonia were
required, and one sheet of 40-foot X
100-foot, 6-mil-thickness black plas-
tic was used. Total costs (1991) are
approximately $570.00 per stack
(Table 1). With 43 tons of 15%
moisture hay (36.5 tons on a dry
matter basis), this equals $13.25
per ton on a 15% moisture basis and
$15.62 per ton on a dry matter basis
to ammoniate hay.


Plastic ($100.00/roll)
Anhydrous ammonia (2924 Ibs x $.13/lb)
Labor (10 hours x $5.00/hr)
Tractor (1 hour x $20.00/hr)
Miscellaneous equipment
Total cost per stack:


(43 tons hay/stack, as-is)

(36.5 tons hay/stack, dry matter)


Cost per ton, as-is:

Cost per ton, dry matter:


ton shown in Table 1 are reduced to
approximately $9.00 per ton.

Anhydrous ammonia has anti-
microbial effects. In several cases
livestock producers have ammoni-
ated hay that was baled too wet
(about 25% moisture). Ammonia
inhibited mold growth, and the hay
was fed successfully. In another
case a livestock producer baled for-
age shortly after cutting. The in-
tention was to bale the forage wet
and treat it with anhydrous ammo-
nia at 4% of the forage dry matter
to inhibit spoilage and mold
growth, and improve feeding value.
The baled forage was very wet
(about 60% moisture). Anhydrous
ammonia has a strong attraction for
water, and the resulting treated
forage had a strong ammonia odor
which reduced intake by yearling


$100.00
380.12
50.00
20.00
20.00
$570.12

$13.25

$15.62


a Calculations are based on the following assumptions: 86 round bales, each bale weighs
1000 Ibs, hay dry matter is 85%, hay is ammoniated at 4% of the forage dry matter, plastic is
a 40 X 100 foot sheet of 6-mil thickness.


Non-nutritional benefits
of ammoniated hay
Cattle waste less ammoniated
hay than nontreated hay. Losses of
25% or more can be obtained in
weathered nontreated hay. Wastes
of 10% or less are observed with
ammoniated hay. If losses due to
waste are considered, ammoniation
costs of approximately $15.00 per


cattle. Because of potential intake
problems, it is recommended that
forage greater than 25 to 30% mois-
ture content not be treated with an-
hydrous ammonia at 4% of the for-
age dry matter. Hay that is 25 to
30% moisture should be ammoni-
ated shortly after baling to reduce
heating that occurs in wet hay.


Some producers treat silage or
haylage with anhydrous ammonia
at 1% of the forage dry matter. Ap-
plication of anhydrous ammonia at
1% of the forage dry matter yields
different results compared to am-
moniation at 4% of the forage dry
matter. Treatment at 1% of the for-
age dry matter limits mold growth
and can be used successfully with
wet (65% moisture) forage, but does
not enhance forage nutritional
value to a large extent.

Nutritional benefits of
ammoniated hay
Table 2 summarizes results from
several research trials conducted in
Florida comparing nontreated and
ammoniated tropical grass hay.
Nontreated hays were low in qual-
ity, and typical of most hay pro-
duced in Florida. Comparison of
hays across trials is not valid be-
cause hays were produced in differ-
ent years and were of different
maturities.

Ammonia treatment increases
the CP concentration of hay (Table
2). The increase in CP concentra-
tion is due to non-protein-nitrogen
addition from ammonia. This non-
protein-nitrogen from ammonia has
a protein value similar to that of
urea which is found in many liquid
and dry supplements. For young
growing cattle, utilization of this
non-protein-nitrogen is not as good
as protein utilization from a natural
protein source such as cottonseed
meal or soybean meal. Although
CP concentration of hay is in-
creased by ammoniation, other nu-
tritional effects are usually more
important. From an economical
standpoint, however, the increased
CP concentration is important be-
cause standard molasses at approxi-
mately $80.00 per ton can be fed
rather than a urea-fortified molas-
ses product at approximately
$120.00 per ton. Because of the non-
protein-nitrogen contribution from
anhydrous ammonia in ammoniated


Table 1. Costs of treating hay with anhydrous ammonia"


Total cost








Table 2. Chemical composition and in vitro digestion of nontreated and ammoniated hay

In vitro
Neutral organic
Crude detergent matter
protein, % fiber, % digestion, %a

Trial 1: Limpograss hay
Nontreated 3.2 88.9 46.2
Ammoniated 10.3 80.9 62.5

Trial 2: Stargrass hay
Nontreated 4.4 87.6 35.0
Ammoniated 9.4 80.1 45.7

Trial 3: Bermudagrass hay
Nontreated 7.5 83.3 40.5
Ammoniated 14.1 79.3 57.2

Trial 4: Bermuda-Bahiagrass hay
Nontreated 4.2 81.9 42.2
Ammoniated 12.7 81.8 53.3

a A measure of digestibility by cattle (related to total digestible nutrients, TDN)


hay, supplemental feeds containing
urea should not be fed with ammo-
niated hay.

Ammoniation improves feeding
value of the forage by a chemical
breakdown of plant fibers resulting
in a better opportunity for rumen
bacteria to attach to the fiber and
digest the ammoniated hay. Neu-
tral detergent fiber concentration,
which is a measure of the cell wall
content of a forage, is reduced by
ammoniation (Table 2). This con-
tributes to the greater in vitro or-
ganic matter digestion of ammoni-
ited compared to nontreated hay.
:n vitro organic matter digestion is
a measure of the energy content of a
Ibrage, and is usually 10 to 15 per-
centage units greater in ammoni-
ated than in nontreated hay.

Performance of yearling steers
fed nontreated or ammoniated hay
is shown in Table 3. Mature
stargrass hay, typical of that pro-
duced in Florida, was used. The
nontreated hay was low in CP and


IVOMD and high in NDF. One-half
of the hay was left nontreated and
one-half was ammoniated according
to the procedures described above.
Ammoniation increased the CP and
IVOMD and reduced the NDF of the
stargrass hay.

Brahman crossbred steers (435
lbs; 8 months of age) were placed in
drylot (3 pens per treatment, 7 head
per pen) from January through
April, and fed ad libitum quantities
of either the nontreated or ammoni-
ated stargrass hay. All steers were
fed 2.0 lbs/head/day of a supplement
containing corn, cottonseed meal,
minerals and vitamins. Steers fed
ammoniated hay consumed 20%
more hay than those fed nontreated
hay (Table 3). Increased digestibil-
ity of ammoniated compared to
nontreated hay and increased
intake of ammoniated compared to


Table 3. Performance of yearling cattle fed nontreated or ammoniated hay

Item Nontreated Ammoniated SEa


Laboratory analyses

CP 4.4 8.1
NDF 87.4 82.2
IVOMD 30.8 50.6

Daily feed intake, Ibs as-is

Hay 9.8b 11.7c .37
Supplement 2.0 2.0
Total 11.8b 13.7c .37

Daily gain, Ibs .3b .90 .07
Feed costs, $/day .42 .54
Yardage, $/day .15 .15
Total, $/day .57 .69
Cost of gain, $/lb 1.90 .77

CP = crude protein, NDF = neutral detergent fiber, IVOMD = in vitro organic matter digestion.
Costs are based on $35.00/ton for nontreated hay, $50.00/ton for ammoniated hay, $250.00/
ton for supplement.
a SE = standard error of the mean.
b,c Values in the same row with a different superscript are significantly different (P < 0.05).









nontreated hay are additive, result-
ing in a large increase in daily gain.
Steers fed nontreated hay plus a
natural protein-based supplement
gained .3 lbs/day, while steers fed
ammoniated hay plus a natural
protein based supplement gained .9
lbs/day. Daily gains of approxi-
mately 1.0 lb/day are typical for
yearling cattle fed ammoniated hay
plus a natural protein such as cot-
tonseed meal. Cost of gain for steers
fed nontreated hay plus the natural
protein-based supplement was
high, and was decreased for steers
fed ammoniated hay plus the natu-
ral protein-based supplement.


Forage maturity and
ammoniation
A practical question arises
whether hay fields should be man-
aged to harvest less mature forage
(5-weeks regrowth), or whether
grass should be allowed to grow to
obtain greater yield, and the result-
ing mature, low-quality forage am-
moniated to improve its feeding
value. To answer this question,
stargrass hay was harvested after
5- and 10-weeks regrowth. One-
half of the bales of each maturity
were left nontreated, and the
remaining one-half were


ammoniated. Weaned Brahman
crossbred heifers (450 lbs; 8 months
of age) were placed on bahiagrass
pasture from October through Feb-
ruary (3 pastures per treatment, 7
head per pasture) and fed one of the
four hays described above. All heif-
ers were fed 1.0 lb supplement/
head/day. The supplement con-
tained corn, cottonseed meal, min-
erals and vitamins.

Nontreated, 5-week-regrowth
hay was greater in CP and IVOMD
than was the nontreated, 10-week-
regrowth hay (Table 4). Ammonia-
tion increased the CP and IVOMD


Table 4. Performance of heifers fed stargrass hay at two regrowth intervals either nontreated or ammoniated

5 week regrowth 10 week regrowth

Nontreated Ammoniated Nontreated Ammoniated SEa


Laboratory analyses
CP 10.6 14.4 4.4 9.4
NDF 85.0 74.0 87.6 80.1
IVOMD 46.5 58.2 35.0 45.7

Daily feed intake, Ibs as-is

Hay 10.2 11.7c 6.5b 11.90 .75
Supplement 1.0 1.0 1.0 1.0
Total 11.20 12.70 7.5b 12.90 .75

Daily gain, Ibs .50 .8d .0b .7d .09

Feed costs, $/day .39 .51 .24 .43

Yardage, $/day .15 .15 .15 .15

Total, $/day .54 .66 .39 .58

Cost of gain, $/lb 1.08 .83 .83

CP = crude protein, NDF = neutral detergent fiber, IVOMD = in vitro organic matter digestion.
Costs are based on $50.00/ton for nontreated 5 week regrowth hay, $65.00/ton for ammoniated 5 week regrowth hay, $35.00/ton for nontreated
10 week regrowth hay, $50.00/ton for ammoniated 10 week regrowth hay, $250.00/ton for supplement.
a SE = standard error of the mean.
b,c,d Values in the same row with a different superscript are significantly different (P < 0.05).








of both hay maturities, however
the response was greater in the
10-week compared to the 5-week
regrowth hay. Heifers fed the
nontreated, 5-week-regrowth hay
plus the natural protein-based
supplement ate 57% more feed and
gained much more weight than
heifers fed the nontreated, 10-week-
regrowth hay plus the natural pro-
tein-based supplement. Ammonia-
tion of the 5-week-regrowth hay did
not improve hay intake or daily
gain to a large degree compared to
nontreated, 5-week-regrowth hay.
Heifers fed ammoniated, 10-week-
regrowth hay plus the natural pro-
tein-based supplement consumed
83% more hay and gained much
more weight than those fed the
nontreated, 10-week-regrowth hay
plus the natural protein-based
supplement.

Daily gain and cost of gain by
heifers fed the ammoniated, 10-
week-regrowth hay plus the natural
protein-based supplement was
better than that by heifers fed the
nontreated, 5-week-regrowth hay
plus the natural protein-based
supplement. This suggests that
harvest of some hay fields can be
delayed to obtain additional yield,
and the resulting low-quality hay
ammoniated to provide a hay of at
least similar feeding value to that
of a less mature, nontreated hay.
Also, if wet weather prevents har-
vest of high-quality hay, ammonia-
tion of more mature hay would be
an alternative to supplementation.
Daily gain by heifers fed ammoni-
ated hay plus a natural protein-
based supplement is probably not
acceptable for developing heifers to
be bred as yearlings, but economics
may favor energy supplementation
of ammoniated compared to
nontreated hay.


Supplementation or
ammoniation
Another practical question arises
as to whether an energy/protein
supplement should be purchased
and fed with nontreated hay, or
nontreated hay should be ammoni-
ated. To answer this question, two
trials were conducted to evaluate
ammoniation or molasses supple-
mentation of mature forage. In
both trials steers were housed in
drylot and fed one of the following
three treatments: (1) nontreated
forage (2) nontreated forage plus
molasses or (3) ammoniated forage.
In trial 1 the forage was mature
limpograss hay, and in trial 2 the
forage was rice straw. In trial 1,
Brahman crossbred steers averag-
ing 500 lbs and 8 months of age
were used, and in trial 2, Brahman
crossbred steers averaging 600 lbs
and 12 months of age were used. In
trial 1, all steers were fed 1.0 lb
supplement/head/day, and steers
fed molasses received 4.0 lbs molas-
ses/head/day. In trial 2, all steers
were fed 1.5 lb supplement/head/
day, and steers fed molasses re-
ceived 4.5 lbs molasses/head/day.
In both trials, the supplement con-
tained corn, cottonseed meal, min-
erals and vitamins.

Limpograss hay used in trial 1
was very low in CP, high in NDF
fiber and low in IVOMD (Table 5).
Rice straw produced in Florida is
generally greater in CP than that
produced in other parts of the coun-
try because of the high organic mat-
ter content of south-Florida soils.
Ammoniation increased the CP
and IVOMD and reduced the NDF
of both forages.

In trial 1, steers on all treat-
ments performed better than
expected (Table 5). In both trials,
steers fed ammoniated hay plus the
natural protein-based supplement
ate more hay, gained more weight


and had a less expensive cost of
gain than did steers fed nontreated
hay plus the natural protein-based
supplement. Steers fed nontreated
hay plus molasses-natural protein
had reduced hay intake compared
to steers fed nontreated hay plus
the natural protein-based supple-
ment. This response is termed a
substitution effect, and must be
considered when supplementing
forage-based diets. Steers fed
nontreated hay plus molasses-natu-
ral protein gained more weight and
had a less expensive cost of gain
compared to steers fed nontreated
hay plus the natural protein-based
supplement.

Contrasting the performance ob-
tained from nontreated hay plus
molasses-natural protein compared
to that obtained from ammoniated
hay plus the natural protein-based
supplement is important. Steers
fed ammoniated hay plus natural
protein had a greater daily gain in
trial 1, and a similar daily gain in
trial 2 compared to steers fed
nontreated hay plus molasses-natu-
ral protein. This indicates that
cattle fed ammoniated hay plus
natural protein perform at least as
well as cattle fed nontreated hay
plus molasses-natural protein.
Steers fed nontreated hay plus mo-
lasses-natural protein consumed
4.0 and 4.5 lbs of molasses per day
which is typical for cattle of that
age and weight. Therefore, if addi-
tional daily gain is desired from
cattle fed nontreated hay plus mo-
lasses-natural protein, then addi-
tional supplement or another type
of supplement would have to be fed.
Steers fed ammoniated hay plus
natural protein were not supple-
mented with additional energy.
Performance of cattle fed ammoni-
ated hay plus natural protein
may be enhanced by energy
supplementation.








Table 5. Performance of steers fed limpograss hay (trial 1) or rice straw (trial 2), either supplemented with cane molasses or ammoniated

Trial 1, Limpograss hay Trial 2, Rice straw

Nontreated Nontreated
Nontreated + molasses Ammoniated SEa Nontreated + molasses Ammoniated SEa

Laboratory analyses
CP 3.2 10.3 5.6 11.0
NDF 88.9 80.9 76.9 72.7
IVOMD 46.2 62.5 37.0 54.4
Daily feed, Ibs as-is

Hay 9.7b 8.4b 11.7c .95 11.7c 10.5b 15.0d .51
Supplement 1.0 1.0 1.0 1.5 1.5 1.5
Molasses 4.0 4.5
Daily gain, Ibs .6b .90 1.2d .20 .5b .9c .9 .09
Feed costs, $/day .30 .44 .42 .39 .55 .57
Yardage, $/day .15 .15 .15 .15 .15 .15
Total, $/day .45 .59 .57 .54 .70 .72
Cost of gain, $/lb .75 .66 .48 1.08 .78 .80

CP = crude protein, NDF = neutral detergent fiber, IVOMD = in vitro organic matter digestion.
Costs are based on $35.00/ton for nontreated forage, $50.00/ton for ammoniated forage, $250/ton for supplement, $80.00/ton for molasses
a SE = standard error of the mean.
b,c,d Within a trial, values in the same row with a different superscript are significantly different (P < 0.05).


Feeding programs
including ammoniated
hay
Performance of cattle fed ammo-
niated hay may be increased by pro-
tein and/or energy supplementation
of ammoniated hay. To evaluate
this, a growth trial was conducted
to evaluate molasses and cottonseed
meal (CSM) supplementation of am-
moniated hay. Brahman crossbred
steers (480 lbs; 8 months of age)
were placed on bahiagrass pasture
from October through February and
fed ammoniated stargrass hay plus
the following four supplementation
treatments: (1) control (no supple-
ment), (2) ad libitum quantities of
standard molasses, (3) 1.0 lb CSM/
head/day and (4) ad libitum quanti-
ties of standard molasses plus 1.0 lb
CSM/head/day. For the ammoni-
ated hay plus molasses-CSM diet,
molasses and CSM were mixed into


a slurry. Molasses alone, CSM
alone, and the molasses-CSM slurry
were fed on Monday, Wednesday
and Friday.

Steers supplemented with molas-
ses or molasses-CSM had reduced
hay intake compared to steers fed
ammoniated hay alone (Table 6).
Molasses intake was increased
when CSM was added (5.9 vs 7.0
lbs).

Steers fed ammoniated hay alone
gained .5 lbs/day. This hay was ad-
equate to meet maintenance re-
quirements plus provide a small
amount of gain, and formed a base
to which supplementation programs
could be applied. Both molasses
and CSM supplementation im-
proved daily gain and cost of gain,
but the response to protein (CSM)
was greater than the response to
energy (molasses). Crude protein


concentration of the hay before am-
moniation was 6%, and after treat-
ment was 11%. The increase was
due to non-protein-nitrogen addi-
tion from ammonia which is similar
to nitrogen from urea. This demon-
strates the importance of feeding
natural protein (cottonseed meal,
soybean meal, feather meal) to
cattle with high nutrient require-
ments such as developing heifers.
Steers fed ammoniated hay plus
molasses-CSM slurry gained 1.7
lbs/day. The cost of gain ($.55/lb) is
attractive in today's markets for
either developing heifers or
backgrounding steers. Even though
the research was conducted with
steers, this feeding program (ammo-
niated hay plus molasses-natural
protein slurry) can provide the level
of performance necessary to develop
a weaned heifer so that she can be
bred as a yearling.









Table 6. Performance of steers fed ammoniated stargrass hay alone or supplemented with molasses and/or cottonseed meal
Treatment

Ammoniated Ammoniated Ammoniated
Ammoniated hay + hay + hay + molasses
hay alone molasses CSM + CSM SEa

Daily feed intake, Ibs as-is

Hay 14.4c 10.0b 13.4c 12.2b .43
Molasses 5.9b 7.0 .26
CSM 1.2 1.2
Daily gain, Ibs .5b .8c 1.0" 1.7d .10
Feed costs, $/day .36 .49 .52 .77
Yardage, $/day .15 .15 .15 .15
Total, $/day .51 .64 .67 .92
Cost of gain, $/lb 1.11 .83 .65 .55

Costs are based on $50.00/ton for ammoniated hay, $80.00/ton for molasses,
$300.00/ton for cottonseed meal.
a SE = standard error of the mean.
b,c,d Values in the same row with a different superscript are significantly different (P < 0.05).


Precautions for the use
of ammoniated hay
Recently, reports have surfaced
concerning toxic effects in cattle fed
ammoniated hay. Symptoms in-
clude restlessness, impaired vision,
loss of balance, sudden stampeding
and running in circles. Some
deaths have been reported, prima-
rily in young calves (less than 1
month old) nursing cows that were
fed ammoniated hay. Earlier re-
ports suggested that ammoniated
hay toxicity occurred in high-qual-
ity forages, forages that were high
in moisture, or in hay that was
treated with high levels (3% or
greater) of ammonia. Recent re-
search shows that this problem is
not dependent on ammoniation
level, moisture level, kind or quality
of hay, but is dependent upon pro-
longed high temperatures during
the ammoniation process. It ap-
pears that high temperatures in the
hay stack at the time of treatment
sometimes causes a toxic compound
to be formed. This compound
is not always produced during
ammoniation. If the toxic com-


pound is produced, in most cases it
is not present in large enough quan-
tities to produce symptoms in
yearling cattle or mature cows, but
can be transferred through the milk
to affect the calf.

Although this syndrome has
dramatic symptoms, it has devel-
oped in only a few situations. We
have fed approximately 1000 head
of yearling cattle over six years at
the AREC-Ona and not observed
any toxicity symptoms. In the one
cow/calf trial conducted at the
AREC-Ona and the four cow/calf
trials conducted on Florida
ranches, no toxicity symptoms were
observed. Two producers reported a
higher than expected death rate
in young calves from cows fed
ammoniated hay. It was not deter-
mined if ammoniated hay caused
the deaths directly, but it remains a
possibility.

At this time, limited information
is known about this syndrome or
the compound that is responsible.
Because of the possibility of toxicity
symptoms in young calves, we rec-


ommend that ammoniated hay not
be fed to lactating cows. Ammoni-
ated hay should be reserved for
feeding to developing heifers, herd
bulls or cull cows that are held over
the winter to obtain a greater price
in the spring market.

Recommendations
1. Procedures for treating hay with
anhydrous ammonia can be
adapted for each situation. An
air-tight seal to keep the ammo-
nia from escaping is essential.
The key is to minimize costs of
materials and labor for each spe-
cific situation.

2. Tropical grass hay should be
treated with anhydrous ammonia
at 4% of the forage dry matter.
Hay should remain sealed for 30
days before feeding.

3. Hay harvested after 5 to 6 weeks
regrowth should be fed
nontreated. If harvest is delayed,
then feeding value of the result-
ing mature forage can be in-
creased to that of a 5-week-
regrowth forage by ammoniation.









4. Only a portion of the hay pro-
duced or purchased should be
ammoniated. Nontreated hay
should be fed to lactating cows,
while ammoniated hay can be fed
to developing heifers, herd bulls
or cull cows.

5. A diet consisting of ammoniated
hay plus molasses-natural pro-
tein can provide the nutrition
necessary to develop a heifer dur-
ing her first winter after weaning
so that she will be ready to breed
as a yearling.

Literature cited
Beef-Forage Practices In South
Central Florida. 1986 Summary.
Bulletin PE-9. Institute of Food and
Agricultural Sciences, University of
Florida, Gainesville, FL.

Brown, W.F., J.E. Moore, W.E.
Kunkle, C.G. Chambliss and K.M.
Portier. 1990. Forage testing using
near infrared reflectance spectros-
copy. Journal of Animal Science.
68:1416.

Florida Agricultural Statistics.
Livestock Summary. 1989. Florida
Agricultural Statistics Service.
1222 Woodward Street. Orlando,
FL.

Beef, Forage, Range Practices in
Southwest Florida, 1990 Prelimi-
nary Results. Southwest Florida
Range and Forage Quality Program,
May 21, 1991. Southwest Florida
Research and Education Center,
Immokalee, FL.

Selected publications
concerning ammoniated
hay

Station reports
Kunkle, W.E., R. Goff and J.
Durrance. 1983. Anhydrous
ammonia treatment of low qual-
ity hay. Florida Beef Cattle
Research Report. Page 107.


Kunkle, W.E., J.F. Hentges, Jr. and
J.G. Wasdin. 1984. Effect of
anhydrous ammonia treatment
of hay and supplemental protein
on the performance of lactating
beef cows. Florida Beef Cattle
Research Report. Page 64.

Brown, W.F. 1985. Anhydrous
ammonia treatment of mature
hemarthria hay. Florida Beef
Cattle Research Report.
Page 46.

Brown, W.F. 1986. Forage quality
and ammoniation of low quality
forages. Cattle and Forage Field
Day. AREC-Ona Research Re-
port RC 86-4. Page 24.
University of Florida, Ona, FL.

Brown, W.F. 1986. Ammoniation
of tropical forages to increase
nutritive value. International
Conference on Livestock and
Poultry in the Tropics.
Gainesville, FL. Page B-20.

Kunkle, W.E. 1987. Ammonia
treatment of perennial forages.
International Conference on
Livestock and Poultry in the
Tropics. Gainesville, FL.
Page A-19.

Brown, W.F. 1987. Forage quality
and ammonia treatment of hay.
Cattle and Forage Field Day.
AREC-Ona Research Report RC
87-5. Page 19. University of
Florida, Ona, FL.

Brown, W.F. 1989. Use of ammoni-
ated hay animal performance.
Proceedings of the 45th Southern
Pasture and Forage Crop Im-
provement Conference. Little
Rock, Arkansas. Page 54. (Na-
tional Technical Information
Service, 5285 Port Royal Road,
Springfield, VA 22161).

Brown, W.F. 1989. Molasses and
natural protein supplementation
of ammoniated hay for yearling


cattle. Winter Feeding Field
Day. AREC-Ona Report RC 89-3.
University of Florida, Ona, FL.

Brown, W.F. and D.D. Johnson.
1991. Energy and protein
supplementation of ammoniated
hay for cull cows. Florida Beef
Cattle Research Report. Page 50.

Brown, W.F. 1991. Ammoniation
or cane molasses supplementa-
tion of tropical grass hay.
Florida Beef Cattle Research
Report. Page 58.

Brown, W.F. 1991. Molasses and
cottonseed meal supplementation
of ammoniated hay for yearling
cattle. Florida Beef Cattle
Research Report. Page 63.

Journal articles
Brown, W.F., J.D. Phillips and D.B.
Jones. 1987. Ammoniation or
cane molasses supplementation
of low quality forages. Journal of
Animal Science. Volume 64.
Page 1205.

Brown, W.F. 1988. Maturity and
ammoniation effects on the feed-
ing value of tropical grass hay.
Journal of Animal Science.
Volume 66. Page 2224.

Brown, W.F. 1990. Ammoniation
or cane molasses supplementa-
tion of tropical grass hay.
Journal of Production Agricul-
ture. Volume 3. Page 377.

Brown, W.F. and D.D. Johnson.
1990. Effects of energy and
protein supplementation of am-
moniated tropical grass hay on
the growth and carcass charac-
teristics of cull cows. Journal of
Animal Science. Volume 69.
Page 348.























































































All programs and related activities sponsored or assisted by the Florida Agricultural Experiment Station are open to all persons regardless of race, color, national origin, age, sex,
or handicap. Printed 5/92. ISSN0096607X




University of Florida Home Page
© 2004 - 2010 University of Florida George A. Smathers Libraries.
All rights reserved.

Acceptable Use, Copyright, and Disclaimer Statement
Last updated October 10, 2010 - - mvs