GROWTH AND CARCASS CHARACTERISTICS OF BULLS, STEERS, AND PARTIAL CASTRATES KEPT ON RANGE FOR THE FIRST YEAR OF LIFE AND THEN FATTENED

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Abstract
The growth rate of bulls, steers castrated at 8 and 26 weeks of age, and steers partially castrated at 8 weeks of age did not differ before weaning in October at an average age of 181 days, or during the ensuing winter. During the subsequent finishing period in the feedlot, the rate and efficiency of growth of the partial castrates exceeded that of the steers but was less than that of the bulls. As a result, partial castrates reached the target slaughter weight of 440 kg 21 days earlier than the steers but 21 days later than the bulls. Varying the level of protein in the rations fed during the first 15 weeks of the feedlot period had no effect on rate or efficiency of gain.The percent fat in the 11th rib-cut and the depth of fat over the longissimus dorsi were less in bulls than in steers or partial castrates, and consequently the carcass grades of the bulls were generally lower. The percent separable muscle, estimated from a prediction equation, was greater in bulls than in steers and partial castrates.