THE EFFECT OF FEED RESTRICTION ON FEED EFFICIENCIES AND CARCASSES OF CHAROLAIS × HEREFORD STEERS

Abstract

Eighty Charolais × Hereford steer calves averaging 253 kg were fed an all-concentrate diet in amounts to allow gains of about 0.7 kg per day (L) or 0.9 kg per day (M), or were given the diet ad libitum to permit a high rate of gain (H). The feeding levels were arranged to provide five feeding programs of LLH, LMH, HML, MMM, and HHH, with each of the first two periods of 12-wk duration and a final period that varied in length because steers were marketed as they reached about 520 kg. The steers fed on the HHH program consumed the most feed per day, gained the fastest, and required the least time to reach market weight. The digestible energy requirement of 109.4 MJ/kg gain for the HHH steers was similar to that of steers on the LLH program and only marginally greater than that of steers on the LMH, HML, and MMM programs. Steers that were restricted in feed intake during part or all of the experiment had leaner carcasses than those that were given the diet ad libitum throughout. All carcasses of steers that were restricted in feed during part or all of the feeding period graded A1 or A2, whereas 25% of the steers fed ad libitum throughout the feeding period graded A3. An economic comparison was made using combinations of low and high grain to forage price ratios and small and large price differentials between A2 and A3 carcass grades. The LMH program ranked first in net returns, the MMM program ranked second under two economic situations, and the HHH ranked second under two other economic situations. Key words: Feed restriction, carcass, steers, LP model