Everglades Station Mimeo Report 61-20 June 22, 1961
The Value of Different Levels of Resernine
For Steers Fattened on Pasture / _/
H. L. Chapman, Jr. and C. E. Hainesl/
Reserpine is a tertiary alkaloid, isolated from Rauwolfia serpentina,
and possesses the sedative and hypotensive activity obtained in the crude
root. Pharmacological studies with reserpine have demonstrated that
administration of the drug results in parasympathetic activity, manifested
by increased tone of the gastro intestinal tract, increased gastric secretion,
a bradycardia and miosis.
Interest in the use of various tranquilizing drugs, derived from the
Rauwolfia plant, in cattle feeding has been exemplified in recent studies.
However, results from these have been variable. A review of these studies
suggest that the level of dose may not be sufficiently well defined. The
purpose of the two studies reported in this paper was to determine the effect
of different levels of reserpine intake upon cattle, being fattened on pasture.
In the first experiment, initiated July 27, 1959, forty two-year-old
Brahman x Angus steers having an average initial weight of 742 pounds were
divided into 5 lots of 8 animals each on the basis of weight and condition.
The steers were allotted to treatment randomly, within weight group. All
groups were full fed a concentrate ration, on pasture, for 98 days. The
pasture forage was Roselawn St. Augustinegrass. The concentrate ration was
comprised of 48.7 percent ground snapped corn, 40 percent dried citrus pulp,
10 percent 36% cottonseed meal, 0.8 percent Urea-262 and 0.5 percent of a
complete mineral mixture. Reserpine (Serpasil, CIBA Pharmaceutical Company)
was administered in the feed at the rate of 0, 0.5, 1.0, 2.0 and 4.0 mg. per
During the second experiment 46 Brahman x Angus yearling steers, having
an average initial weight of 664 pounds were divided into three groups, on
the basis of weight and condition. This study was initiated May 25, 1960
and conducted for a period of 128 days. The concentrate ration and pasturery
forage was the same as during the first study. Levels of 0, 0.25 and O-'aimg '
of reserpine (Serpasil, CIBA Pharmaceutical Company) were fed per anil .a
daily to the three groups.
L/ Acknowledgement is made to L. V. Morris, Tom Swager, J. V. Mc da
others who assisted in the conduction of these experiments. \cs\
2/ These studies were supported in part by a grant-in-aid furnished by, CIBA
Pharmaceutical Company, Summit, New Jersey.
/ Associate Animal Nutritionist and Assistant Animal Husbandman, Everglades
Experiment Station, Belle Glade, Florida.
Carcass data was obtained for both studies, with the exception of
carcass grades during the first trial. Therefore, increase in slaughter
grade is not presented for this trial. The effect of level of reserpine
upon intransit shrink, dressing percent and 48-hour cooler shrink was also
determined. Live weights were taken before and after shipment and carcass
weights were taken at the time of slaughter and 48 hours following slaughter.
Dressing percent was determined by dividing the weight at the packing house
into the hot carcass weight; cooler shrink by dividing the hot carcass weight
into the actual pounds of shrink during the 48-hour period in the cooler.
During the second experiment, initial slaughter grades were assigned by a
committee of three graders and the final carcass grades given by a Federal
meat grader. The steers in the second study had an average initial slaughter
grade of high utility.
Results and Discussion
The results of the first study are presented in table 1. The average
daily gain per animal was highest for the steers receiving 0.5 and 1.0 mg.
level of the tranquilizer, being 2.22 and 2.28 pounds as compared to 2.10
pounds for the control group. The average gain was lower for the groups
receiving the two higher levels of reserpine. There was no evident sedation
in the steers receiving the higher levels of the drug and feed consumption
was approximately equal to the other groups. The rates of gain of the five
groups were not significantly different statiotitcally due to variation with-
in treatment groups.
Upon completion of the feeding period the steers were transported appro-
ximately 6 miles to a slaughter house. As shown in table 1, the average
intransit shrink was highest in the group receiving the 0.5 mg. levels and
lowest for the steers on the two higher levels. Average dressing percent was
higher than the control group for the groups receiving 0.5, 1.0 and 2.0 mg.
of the drug. Cooler shrink was approximately the same for all five groups.
While these data were not significantly different, statistically, they indi-
cate a definite advantage for the steers receiving the two lower levels of
the tranquilizer, indicating that levels used in other reports may be too
high for optimum results.
Table 1. Summary of average weight gains, feed utilizing and carcass data
of steers on various levels of reserpine. (Experiment I, July 27,
1959- November 2, 1959, 98 days).
Level of Reserpine (mg/an/day) 0 0.5 1.0 2.0 4.0
Number steers 8 8 8 8 8
Initial weight (Ibs.) 745 726 741 751 746
Final weight (Ibs.) 951 944 964 952 941
Total gain (Ibs.) 206 218 223 201 195
Daily gain (Ibs.) 2.10 2.22 2.28 2.05 1.99
Daily feed consumption (Ibs.) 20.0 19.5 21.1 19.6 19.4
Feed/lb. gain (lbs.) 9.5 8.8 9.3 9.6 9.7
Intransit shrink (%) 2.0 2.6 2.0 1.7 1.6
Dressing percent (%) 61.9 62.1 62.6 62.4 61.8
48-hr. cooler shrink (%) 3.3 3.3 3.4 3.7 3.6
The results obtained in the second feeding experiment are presented in
table 2. The gains during the second trial were lower than usually obtained
from steers having this level of feed intake, but the results of the second
experiment were in agreement with the first, insofar as the effect of the
drug on rate of gain. The average daily gain was 1.69, 1.86 and 1.95 pounds
for the control group and the groups receiving 0.25 and 0.50 mg. of the drug,
representing an increase of 8 and 13 percent, respectively. Differences in
weight gains were consistent throughout the feeding period. The groups re-
ceiving the drug were consistently higher than the control group. These
differences were statistically significant.
Table 2. Summary of average weight gains, feed utilization and carcass data
of steers on various levels of reserpine (Experiment 2, May 25,
1960-September 30, 1960, 128 days).
Level of Reserpine (mg/an/day) 0 0.25 0.50
Number of steers 15 15 16
Initial weight (lbs.) 667 663 663
Final weight (Ibs.) 883 901 912
Total gain (Ibs.) 216 238 249
Daily gain Ibs.) 1.69 1.86 1.95
Daily feed consumption (Ibs.) 20.3. 20.0 20.1
Feed/lb. gain (Ibs.) 12.0 10.8 10.3
Intransit shrink (M) 6.0 5.8 6.8
Dressing percent (%) 64.5 63.4 63.8
48-hr. cooler shrink (%) 2.0 2.0 1.8
Increase in grade (1/3) 4 4 4
Feed required per pound of gain is usually a function of body weight
and this was the case during the second trial where feed consumption was
relatively equal in all groups. There was no significant effect of treatment
upon intransit shrink, dressing percent or 48-hour cooler shrink during the
second trial. The higher intransit shrink during the second trial, as com-
pared to the first, is due to the steers being transported approximately 250
miles to the packing house. This also resulted in a slightly higher dressing
percent, since the weight at the packing house was considerably shrunk during
the second experiment.