5 AGRICULTURAL RESEARCH CENTER
c Jay, Florida
JAY, ARC RESEARCH REPORT WF75-5 MAY, 1975
ENERGY FEEDS (CORN SILAGE AND GRAIN) FOR GR
BEEF CALVES GRAZING WINTER ANNUAL PASTUWSM/1
J. E. Bertrand and L. S. Dunavin/ /
Small grain crops (wheat, oats, rye, and triticale), ryegAp and c
a mixture for rotational grazing by growing beef ca1 ,vffer a lograzingi
period and a good potential for beef production duringihi' cool seas6pf the ar
in the Panhandle area of Florida. These winter annual pa Sur orages are hig in
protein, minerals, and vitamins (especially vitamin A) on a'd&r ter basi
However, they are high in moisture and slightly low in energy for -oimum owth
by light-weight beef calves. Corn silage with a high grain contend n1440 rn are
good sources of energy and can constitute a large portion of the diet ~ eef
cattle.
The purpose of this study was to determine the supplementary value of energy
feeds (corn silage and grain) for growing beef calves grazing winter annual pastures.
PROCEDURE
Sixty-four light-weight (average 371 pounds), good quality calves of British
breeding, each treated with a 36 mg ear implant of RALGRO (Zeranol a protein
anabolic agent), were weighed and allotted as equally as possible to eight
experimental groups of eight animals each. The eight experimental groups,
utilizing two groups per treatment, were assigned to four feeding regimes as
follows:
1. Corn silage (95%) + concentrate supplement (protein, minerals, and
vitamins) (5%) ration.
2. Rotational grazing of a triticale (FasGro variety "South Blend"), ryegrass
(Gulf), and crimson clover (Dixie) mixture (unsupplemented); four 1.25
acre plots (total 5 acres) for each group initially containing eight calves.
3. Same forage mixture, acreage, and number of calves as 2 above (supplemented
with a 12% protein high-energy ration at the level of 1% of body weight).
4. Same forage mixture, acreage, and number of calves as 2 above (supplemented
with corn silage fed ad libitum).
The triticale was planted in rows 7 inches apart with a grain drill at the
rate of 121 pounds per acre. The ryegrass and crimson clover were seeded over the
triticale with a cultipacker-seeder at the rates of 10 and 8 pounds per acre,
respectively. The first and second rotational pastures for each treatment were
planted on October 30, 1973; while the third and fourth rotational pastures for
each treatment were planted on November 7, 1973.
1/Presented at the 1975 Beef Cattle Short Course, University of Florida, Gainesville.
2/Associate Animal Scientist and Associate Agronomist, respectively, Agricultural
Research Center, Jay.
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A complete fertilizer (8-24-24) was applied at planting time on all pastures
at the rate of 250 pounds per acre. Three applications of 100 pounds per acre each
of ammonium nitrate were made on all pastures during the grazing season.
The corn silage was made from Pioneer variety "3369A" hybrid corn, which
yielded 13.5 tons per acre of 33% dry matter forage. On a dry natter basis, 48%
of the corn silage was grain.
The trial was initiated on December 18, 1973, and terminated when the forage
was completely grazed out (May 28, 1974).
After an overnight shrink (fast from feed and water), individual animal
weights were taken at the beginning and at the end of the trial period. Additional
test animals were added to and removed from the pasture groups as needed to keep
the forage uniformly grazed.
The supplemental ration fed on pasture to two groups of calves was given (tf#"
daily at the level of 1% of body weight. The feed allowances were determined on
the basis of unshrunk 28-day group weights. The corn silage, which was fed to two
groups of calves on pasture, was fed ad libitum. The calves fed in drylot on the
corn silage and concentrate supplement (protein, minerals, and vitamins) ration
were fed once daily in an amount of feed that they would clean-up between feedings.
Feed data were recorded daily.
Each experimental group of calves was rotated between the four pasture plots
assigned to it as required for best utilization of good quality forage.
A mineral mixture (consisting of two parts defluorinated rock phosphate and
one part trace-mineralized salt), plain salt, and clean drinking water were
available to the animals at all times.
RESULTS AND DISCUSSION
The performance and economic data of growing beef calves receiving the four
feeding regimes are listed in Table 2. The over-all performance on all treatments
was considered to be better than average. Beef calves receiving the supplemental
ration on pasture had the largest daily gain per head (2.10 pounds per head),
followed in order by the daily gain (1.89 pounds per head) of unsupplemented beef
calves on pasture, the daily gain (1.73 pounds per head) of beef calves receiving
silage on pasture, and the daily gain (1.73 pounds per head) of beef calves
receiving the silage ration in drylot. Beef calves supplemented with a 12% protein
high-energy ration on pasture at the level of 1% of body weight gained significantly
(P(0.01) faster than calves receiving silage on pasture and the silage ration in
drylot.
The beef gains per acre varied from 740 pounds for calves fed corn silage ad
libitum on pasture down to 590 pounds for unsupplemented beef calves on pasture
(Table 2). The beef gain per acre for calves receiving the supplemental ration on
pasture was 695 pounds. Calves fed corn silage on pasture had the highest stocking
rate per acre (2.66), while unsupplemented calves grazing the pasture mixture had
the lowest stocking rate per acre (1.94). The stocking rate per acre for calves
receiving the supplemental ration on pasture was 2.06.
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The lowest cost of gain ($15.39 per cwt) occurred with unsupplemented calves
on pasture, followed in order by the cost of gain ($20.20 per cwt) with calves
receiving silage on pasture, the cost of gain ($23.33 per cwt) with calves
receiving the supplemental ration on pasture, and the cost of gain ($27.50 per cwt)
with calves receiving the silage ration in drylot (Table 2). These costs were not
excessively high considering the inflationary prices which had to be paid for feed
ingredients, fertilizer, seed, equipment, etc. The large losses per head and per
acre were due to the large negative margin ($19.70 per cwt) which occurred between
the price ($55.70 per cwt) paid for the light-weight calves prior to placing them
on experiment in the fall of 1973 and the value ($36.00 per cwt) of the heavier
animals at the end of the trial (late spring of 1974).
Under the conditions of this study, it appeared that the following statements
were justified:
1. Feeding a 12% protein high-energy ration at the level of 1% of body weight
to calves grazing a mixture of triticale, ryegrass, and crimson clover
increased gain, but also increased the cost of gain.
2. Feeding corn silage ad libitum to calves grazing a mixture of triticale,
ryegrass, and crimson clover increased the carrying capacity (stocking
rate) and beef production per acre, but reduced average daily gain per
animal.
3. Feeding corn silage ad libitum as the energy feed to calves grazing winter
annual pastures compared to feeding a 12% protein high-energy ration at
the level of 1% of body weight to calves grazing winter annual pastures
increased the beef production per acre, decreased the average daily gain
per animal, increased the carrying capacity (stocking rate), and decreased
the cost of gain.
4 -
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Table 1. -- Composition and cost of the concentrate supplement (protein, minerals, and vitamins) and
the pasture supplemental ration (1973-74) ARC, Jay.
Concentrate Supplement(a) Pasture Supplemental Ration(b)
Ingredients % Lb./ton Cost(c) % Lb./ton Cost(c)
Soybean meal (44% protein) 84.793 1696 $161.12 ---- ---
Ground sorghum grain ---- --- ------- 96.94 1939 $67.87
Urea 45% N 3.756 75 3.00 0.50 10 0.40
Salt (trace-mineralized) 3.756 75 2.25 0.50 10 0.30
Defluorinated rock phosphate 7.511 150 7.50 2.00 40 2,00
Zinc bacitracin supplement 0.118 2.4(d) 3.84 0.04 0.8(f) 1.28
Vitamin A supplement 0.066 1.3(e) 0.52 0.02 0.4(g) 0.16
100.000 1999.7 $178.23 100.00 2000.2 $72.01
iark-up(h) 10.00 10.00
$188.23 Ss2.01
(a) Concentrate supplement (protein, minerals, and vitamins) fed in the corn silage ration in
drylot.
(b) Supplemental ration fed on pasture at the level of 1% of body weight.
(c) Based on the following prices: soybean meal (445 protein) = $190.00/ton, ground sorghum grain =
$70.00/ton, urea 45% N = $80.00/ton, salt (trece-mineralized) = $3.00/cwt, defluorinated rock
phosphate = $100.00/ton, Baciferm 40 (zinc bacitracin supplement containing 40 grams of the
antibiotic per pound) = $1.60/lb., and Perma rual 30A (vitamin A supplement containing 30,000
lU/g) = $0.40/lb.
(d) Zinc bacitracin added at the level of 96 g/ton or 48 mg/lb. of concentrate supplement.
(e) Vitauin A added at the level of 17.7 million IU/ton or 8,850 IU/lb. of concentrate supplement.
(f) Zinc bacitracin added at the level of 32 g/ton or 16 mg/lb. of pasture supplemental ration.
(g) Vitamin A added at the level of 5.4 million IU/ton or 2,700 IU/lb. of pasture supplement ration.
(h) Mixing, milling, overage, storage, etc.---$10.0(/ton.
Table 2. -- Performance and economic data of growing beef calves receiving energy
feeds while Prazing winter an ual pastures (1973-74) ARC, Jay.
Item,
Initial no. of animals
Length of trial, days
Avg initial wt, lb.
Avg final wt, lb.
Avg gain/animal, lb.
Avg daily gain, lb.
Gain/acre, lb.
Animal days/acre
Stocking rate/acre(g)
Gain/ncre/dayv lb1
Silage
Ration(a)
15(e)(f)
161
376
654
278
1.73b**
Pasture
Alone(b)
16(e)
161
371
676
305
1.89ab
590
312
1.94
6.67
Pasture
and Grain(c)
16(e)
161
367
705
338
2.10a
695
331
2.06
4.33
Pasture
and Silage(d)
16(e)
161
372
650
278
1.73b
740
428
2.66
4.60
Feed/cwt gain(h)
Corn silage 1837 --- --- 793
Concentrate supplement 97 -- --
Pasture supplemental --- -- 250 --
ration
Feed/animal/day, lb.(h)
Corn silage 31.7 -- ---13.7
Concentrate supplement 1.7 --. --
Pasture supplemental ---- --- 5.3
ration
Feed cost/cwt gain(i) $ 27.50 $ 15.39 $ 23.33 $ 20.20
Net loss/head(j) -$ 50.44 -$ 10.23 -$ 29.48 -$ 29.36
Net loss/acre(j) -$ 19.85 -$ 60.73 -$ 78.10
(a) Corn silage (95%) + concentrate supplement (protein, minerals, and vitamins)
(5%) in drylot.
(b) Rotational grazing of a triticale, ryegrass, and crimson clover mixture
(unsupplemented).
(c) Rotational grazing of a triticale, ryegrass, and crimson clover mixture
(supplemented with a 12% protein high-energy ration at the level of 1% of body
weight).
(d) Rotational grazing of a triticale, ryegrass, and crimson clover mixture
(supplemented with corn silage fed ad libitum).
(e) Initially, two groups of eight steer calves each.
(f) One calf was removed from experiment due to sickness; the data for that
animal were eliminated.
(g) Additional test animals were added and removed as needed to keep the forage
uniformly grazed. In all cases individual animal weights were taken after an
overnight shrink (fast from feed and water).
(h) Does not include pasture.
(i) Corn silage cost = $20.00/ton, concentrate supplement cost = $188.23/ton,
pasture supplemental ration cost = $82.01/ton, and pasture cost = $90.79/acre.
(j) Does not include labor involved in feeding and caring for the animals. Initial
calf cost = $55.70/cwt (includes cost of animals, hauling, veterinary costs,
etc.) and final animal value = $36.00/cwt at the end of the trial.
** Means followed by the same letter are not significantly different at the 1%
level of probability.
Y ---
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