Everglades Station Mimeo 62-20 May 1962
Value of corn silage with Zinc-Bacitracin, Bacitracin or Zymo-Pabst
as a Preservative /
H. L. Chapman, Jr., C. E. Haines and V. E. Green, Jr.-
In an earlier study (1) gains and returns above initial steer values and
feed costs were increased when zinc bacitracin was added to corn silage. The
purposes of the experiment in this report were to obtain additional information
concerning the feeding value of Everglades-produced corn silage and the effect
that different preservatives had upon this feeding value.
.Forty grade Angus steers having an initial average standard slaughter grade,
were divided into 4 equal groups on the basis of weight, grade and previous
treatment. They were then allotted at random to the following experiment' N,
Treatment number Silage Preservative
All experimental animals received a full feed of corn silage in drylot for 105
days. The corn silage was made from Corneli-54 field corn, ensiled when the
ear was in the soft-dough stage and had an average estimated yield of 67.6
bushels per acre of U. S. Number 2 corn. Zinc-Bacitracin and Bacitracin were
each broadcast on the fresh material as it was distributed in the bunker-type
silo at the rate of 5 grams per ton of fresh material. Zymo-pabst was ad-
ministered in the same manner at the rate of 75 grams per ton. The silos were
lined and the silage covered with plastic sheeting to decrease silage spoilage
by keeping the silage stacks as air-tight as possible. Each silo contained two
In addition to the corn silage, the steers received an average of 10 pounds
of a concentrate feed mixture per animal daily. This feed was comprised of
66.0% ground snapped corn, 33.0% 41-percent cottonseed meal and 1% of a com-
plete mineral mixture and cost $3.39 per hundred pounds of mixed feed.
1/ Acknowledgement is made to Mack Barnwell, Enrique Tomeu, J. V. McLeod and
others who assisted in the conduction of this experiment.
2/ This study was supported in part by a grant-in-aid furnished by Pabst
Brewing Company, Milwaukee, Wisconsin, who also supplied the Bacitracin
and Zymo-Pabst. The zinc-bacitracin was furnished by Commercial Solvents,
Inc. Terre Haute, Ind.
3/ Associate Animal Nutritionist, Assistant Animal Husbandman and Associate
Agronomist, respectively, Everglades Experiment Station.
An initial average slaughter grade was placed on each animal by a com-
mittee of three graders. The initial value per animal was based on the price
of steers of similar quality at the Glades Livestock Market Assn. At the
conclusion of the feeding period, the cattle were slaughtered in Miami. The
final value of each animal was the actual average sale receipt. Carcass data
were calculated in the same manner as in the earlier study (1).
The costs of producing the corn silage are presented in Table 1. The
production costs were similar to those obtained in 1961, with the cost of the
edible silage being $9.95 per ton. Spoilage of the ensiled material was higher
than it should have been due to one side of one of the bunker silos breaking.
This resulted in considerable spoilage in two of the test silages.
The average weight changes, carcass data and cost data per steer are
presented in Table 2. There were no statistically significant differences
in any measurement, although steers receiving the Zymo-Pabst-preserved
silage gained an average of 0.20 pounds more daily than did those receiving
the plain silage. Zinc-Bacitracin and Bacitracin did not increase rate of
gain. The steers had an overall average daily intake of approximately 41
pounds of silage. There were slight variations in this as can be seen in
silage costs, but these variations were negligible. Returns were slightly
higher from the steers receiving the silage preserved with Zymo-Pabst due
to the additional weight gains.
1. Chapman, H. L., Jr., C. E. Haines and V. E. Green, Jr. 1962. Feeding
Value of Corn Silage With and Without Zinc-Bacitracin as a Preservative.
EES Mimeo Rpt. 62-12.
Table 1. Summary of production costs for field corn silage.
I. Corn production, per acre
Discing (3 times @1.50)
Planting of seed 1/
Seed cost (15 Ibs. @0.272)
Scratch cultivation (2 times @1.00)
Lay-by and deepen middles
Bird patrol (60 man hrs. for 80 acres)
Wireworm and budworm control 3/
Total costs per acre
15.0 acres of corn @$37.43
II. Cost of ensiling corn
a. Machinery and labor charges/hour
1. Wheel tractor and driver at chopper
2. Wheel tractor and driver hauling
3. Crawler tractor in stack
4. Two men in stack
Total of 20 hours per silo @$9.00
Total cost for two silos
III. Cost of plastic per silo
Cost of plastic for two silos
Total production cost
IV. Total estimated green material ensiled 160 tons
Total silage fed 85.65 ton
Estimated edible silage left 10.00 tons
-/ 500 Ibs. per acre of 0-8-24 with 1.0 CuO, applied broadcast.
3 Wireworm control 4 pound aldrin/acre in fertilizer
Budworm control 1 pt. of 2 lb. heptachlor/acre.
Table 2. Summary of average weight changes, carcass, feed and cost data per
animal for steers on corn silage study, on test 105 days.
None Bacitracin Bacitracin Pabst
Number of animals 10 10 10 10
Final weight (ibs.) 820 814 822 842
Initial weight (Ibs.) 612 612 612 613
Total gain (Ibs.) 208 202 210 229
Daily gain (Ibs.) 1.98 1.92 2.00 2.18
Final slaughter grade 10 10 10 10
Initial slaughter grade 7 7 7 7
Increase in slaughter grade (1/3) 3 3 3 3
Intransit shrink (%) 5.73 4.62 5.39 5.13
Unadjusted dressing percent 60.02 59.44 59.59 60.05
48-hour cooler shrink (%) 2.59 2.58 2.61 2.72
Daily feed consumption
Concentrate feed (Ibs.) 10 10 10 10
Corn silage (Ibs.) 40.5 41 41 41
Final animal value ($) 180.80 181.60 179.20 186.40
Initial animal value ($) 122.40 122.40 122.40 122.60
Total feed costs:
Concentrate feed ($) 35.60 35.60 35.60 35.60
Corn silage 1/ ($) 21.05 21.44 21.31 21.41
Return over initial steer value
and feed costs ($) 1.75 2.16 -0.11 6.79
1/ Does not include cost of silage-preservative.
EES Mimeo 62-20