The effect of hormones on growth rate and carcass quality of fattening lambs and hoggets

Abstract

The effects on average daily gain of a 12 mg. implant of diethylstilboestrol has been tested in male suckling lambs and in male hoggets. In both types stilboestrol produced some mammary stimulation. One case of rectal prolapse was encountered in the hoggets. In suckling lambs, treatment did not significantly increase rate of gain nor significantly affect any of several carcass characteristics studied. In hoggets, treatment produced a highly significant increase in rate of gain (33%), a highly significant increase in pelt weight and a highly significant decrease in the percentage of fat in the last rib section. It produced a non-significant increase in muscle and bone in the last rib section. Carcass score and dressing percentage were not significantly affected by treatment.The oral administration of L-thyroxine to suckling female lambs from 30–70 lb. live-weight did not significantly affect the rate of gain or the carcass characteristics studied.