The Effect of Certain Feed Additives on the Tissues of Fattening Beef Cattle

Abstract

Forty-eight Hereford steers were assigned treatments for a 120-day feeding period in a 2×2×3 factorial designed experiment to determine the main effects and interactions of feeding two levels of chlortetracycline, two levels of stilbestrol and three levels of animal fat upon the composition of the blood, carcass and liver. Dietary animal fat significantly increased the level of plasma fat and decreased the level of plasma carotene, plasma vitamin A, liver carotene and liver vitamin A. It also increased the percent of fat in the carcass but not significantly. Dietary animal fat significantly decreased the effect of stilbestrol on the weight of the seminal vesicles. Animal fat, chlortetracycline and stilbestrol temporarily decreased the level of plasma phosphorus. Chlortetracycline increased the level of plasma carotene and stilbestrol increased the level of plasma vitamin A. Stilbestrol also significantly increased the weight of the seminal vesicles. Neither chlortetracycline or stilbestrol had any effect on the composition of the carcasses or livers of the experimental cattle. Copyright © . .