Use of synthetic oestrogens for promoting weight gains in beef steers grazing on native pastures

Abstract

In two trials on unimproved pasture at the Beef Cattle Pasture Research Station, "Brian Pastures," Gayndah, beef steers implanted at levels of 30 mg and 60 mg with the synthetic hormone hexoestrol made significantly greater liveweight gains than comparable untreated cattle. Treated animals had a slightly better depth of eye muscle and carried less fat cover than the controls. In one trial, carcasses of the control animals graded higher than those of the treated animals, but in the other trial the carcasses of both treated and untreated cattle graded equally well. Certain adverse effects were noted in steers treated at both levels.