''.<..- Everglades Station Mimeo Report EES66-4., September, 1965.
'5 G'- A COMPARISON OF AN ANTIBIOTIC AND AN ENZYME
FOR WEANLING.CALVES 1/
C. E. Haines and R. W. Kidder 2/
When calves are weaned,'they go through a period of adjustment and a
small-amount of a concentrate feed in this period is"usually beneficial to-
growth- and health." Certain feed additives often improve the weight gains'of.
young calves receiving limited amounts of concentrate while on pasture. The
feed additives:may be antibiotics, hormones, vitamins, enzymes and other mate-
rials. They are usually placed in the concentrate feed to furnish individual
aminals with a specific daily intake of the particular additive. In the study
reported herein, an antibiotic was compared to a multiple'enzyme supplement
for weanling calves. The antibiotic was chlortetracycline' (Aureomycin) and
the enzyme supplement' was Zymo-Pabst supplied either continuously or for
portions of the-test period.
One'hundred weanling steer-calves were divided into five equal groups on
the basis"'f weaning weights and breeding. The-calves averaged approximately'
435 pounds at' the beginning of the trial" and were' purebred and crosses of
Angus, Brahman and Hereford breeds. All of the calves:'were weaned during the
last week of June, 1964, and were assigned to the experimental treatments 10
days after weaning. In the short period between weaning and the beginning
of the study, the calves learned to eat a concentrate feed mixture.
Each group of 20 calves was kept in a four-acre pasture of Roselawn St.
Augustinegrass-,and .given.an average -of four pounds .of a...concentrate mixture..
per head daily. The concentrate mixture was composed of ground snapped corn,
citrus pulp, cottonseed meal.and. mineral mixture. The test materials were
placed in the concentrate mixture to provide an'average of either 75 mg of
chlortetracyoline -or. one-half.a .gam of enzyme-supplement per calf daily.
One group served as controls and received the basal concentrate mixture with-
out an additive while a second group was fed the concentrate mixture forti-
fied with chlortetracycline. The enzyme supplement was added to the concen-
trate feed of the remaining three groups for certain periods of the study.
It was used either in the first half, in the second half or for the entire
test'period. The test period was 98 days and the calves were weighed at
frequent intervals- during this period.
A vitamin treatment was superimposed on the study so that one-half of
the calves in each of the feed additive treatments received supplemental
vitamin A. The vitamin was injected at 28-day intervals at the rate of
500,000 I.U. per calf. This phase of the study was included to obtain in-
formation on possible corrective measures for an eye disorder that has been
prevalent in weanling calves at this location for several years.
1/ Test materials were provided by the American Cyanamid Company, Princeton,
New Jersey, and the Premier Malt Products Company, Milwaukee, Wisconsin.
The vitamin A product used in conjunction with this study was supplied by
the Distillation Products Industries, Rochester, New York.
2/ Assistant Animal Husbandman and Animal Husbandman, respectively, Ever-
glades Experiment Station, Belle Glade, Florida.
The greatest response to the additives was secured for chlortetracycline
and it increased gains by an average of 12 pounds per calf over the control
group. This amounts to slightly more than 0.1 pound additional gain per ani-
mal daily by the use of chlortetracycline. The enzyme supplement given in
the first half of the trial and also that provided during the entire test period
improved the rate of gains made by calves. These additional gains were just
slightly below those obtained from the use of chlortetracycline. However,
the enzyme supplement used only in the second half of the trial did not im-
prove the rate of gain. A summary of the weight gains by treatment is
shown in table 1.
The response to vitamin A supplementation.was very inconsistent. In one
of the groups, vitamin A appeared to improve gains while in the other groups
the calves not receiving the vitamin showed a higher rate of gain. A large
percentage of the calves in all groups exhibited the eye disorder and the
vitamin A failed to alter the severity of this condition. Thus, the vita-
min A administered in this manner did not prove beneficial for improving
weight gains or correcting eye disorders. It was suspected that dosage
levels should have been higher to realize beneficial responses. Table 1 also
shows the average gains of the calves by vitamin A treatment within the feed
additive treatments. Statistical analysis of all data indicated that differ-
ences in gains due to either the feed additive treatments or the use of vita-
min A were not significant at the 5% level.
Table 1. Average total gains by feed additive and vitamin A treatment (Ibs.).*
Feed Vitamin A Combined
Additive Yes No Gains
None (Control). 81.5 85.0 83.5
Chlortetracycline 87.5 103.5 95.5
Enzyme, (1st half) 93.0 93.5 93.3
Enzyme, (Whole) 97.5 91.5 94.5
Enzyme, (2nd half) 77.5 85.0 81.3
STen calves in each vitamin treatment group:and 20 in each feed additive