Effects of Testosterone Enanthate on Lamb Carcass Composition and Quality

Abstract

Twenty-six ram and wether lambs were used to evaluate effects of testosterone on carcass composition, fatty acid composition, flavor and tenderness. Significant differences (P<.05) were observed between treated rams and untreated wethers in thickness, color and firmness of fat. Testosterone enanthate treated wethers and normal rams were remarkably similar in all carcass traits, especially fat thickness, kidney fat weight, fat color and fat firmness. However, the untreated rams gained significantly (P<.05) faster than the treated wethers. Percent 14:0, 16:0 and 18:0 decreased in all treatments as weight and age increased and total percent unsaturates increased proportionally. Greatest changes in fatty acid composition occurred between 57 and 68 kg live weight when lambs were between 7 and 8½ months of age. At 68 kg, treated rams' fat contained significantly (P<.05) more 15:0 and 17:1 and less 16:0 than other groups. Differences in short chain fatty acids (<C16) between treatments were small indicating that higher total saturated fatty acids were probably responsible for firmer fat in untreated wethers. Plasma levels of testosterone were significantly (P<.05) higher at 57 kg for treated rams and wethers when compared to untreated rams and wethers. Plasma from untreated rams contained significantly (P<.05) more testosterone than untreated wethers. At 65 kg, effects of testosterone enanthate had disappeared and the only differences were between rams and wethers.