Purdue University-
Agricultural Experiment Station
Lafayette, Indiana
Previous research (A.H. Mimeo 142) has shown that feeding 75 milligrams of an antibiotic per steer daily on a fattening ration of corn silage and Supplement nA" will significantly increase growth rate and improve feed efficiency. Also, one experiment (A.H. Mimeo 166) has indicated that there is an additive effect when an antibiotic (aureomycin) and a female-like hormone (hextrol) are fed together.
This experiment was planned with the following objectives:
(1)	To compare the effect of aureomycin and terramycin on the gain, feed efficiency and carcass quality of yearling steers.
(2)	To compare the effect of an antibiotic vs. an antibiotic-hormone combination on the growth rate, feed efficiency and carcass quality of steers.
(3)	To compare the effect of stilbestrol (diethylstilbestrol) and hexestrol (dihydrodiethylstilbestrol) on yearling steers when fed in combination with either aureomycin or terramycin.
Experimental Plans
One-hundred-sixty yearling Hereford steers, whichvere raised in Wyoming, were purchased at an average price of $>22.00 per hundredweight, delivered to Lafayette, Indiana. Eighty-four of these steers were divided into 7 lots of 12 steers each, with an average beginning weight of 632 pounds.
All the steers were fed on a daily basal ration of corn silage (according to appetite), 3.5 pounds Supplement ,TA” and minerals free choice. No hay or additional corn was fed to these steers.
The treatments were as follows:
EFFECT OF ANTIBIOTICS AND ANTIBIOTIC-HORMONE COMBINATIONS
ON THE GROWTH AND FATTENING OF YEARLING STEERS
W. M. Beeson, T. W. Perry, M. T. Mohler Martin Stob and F.N. Andrews Department of Animal Husbandry
Mimeo A.H. 167 April 27, 1956 (Progress Report)