Effects of Ration Energy and Slaughter Weight on Composition of Empty Body and Carcass Gain of Beef Cattle

Abstract

Empty body and carcass protein, fat, water and ash were determined on 56 Hereford steers representing four slaughter groups. Eight calves were slaughtered at 227 kilograms. The other 48 were fed one of four rations and slaughtered at either 341, 454 or 545 kilograms. The rations consisted of the following ratios of corn to corn silage (dry basis): (A) 30:70; (B) 50:50; (C) 70:30; and (D) 80:20. All 12 treatments were represented by an equal number of experimental animals. Composition of empty body and carcass gain were determined via the comparative slaughter technique. Caloric gains were computed using published gross energy values for protein and fat. The composition of empty body and carcass gain for a given weight were not affected (P<.05) by ration. Fat gain, as a percentage of empty body and carcass gain ranged from 25.11 to 44.02% and 27.48 to 48.57%, respectively, as slaughter weight increased from 341 to 545 kilograms. The greatest increase in fat content occurred after the cattle reached 341 kilograms. Fat, as a percentage of empty body and carcass gain from 454 to 545 kg was 63.37 and 68.26%, respectively. Energy gain per day was less (P<.05) for the cattle fed ration A to 545 kilograms. The following equation was developed to predict empty body weight: −13.577 + .972X, where X refers to kilograms if shrunk live weight (R² =.998). Copyright © 1976. American Society of Animal Science . Copyright 1976 by American Society of Animal Science.