Effects of zeranol on weight gain bone growth and other carcass traits in steers and bulls
Chaudhary, Z.I.; Price, M.A.; Makarechian, M.
Canadian Journal of Animal Science 65(4): 835-840
ISSN/ISBN: 0008-3984 DOI: 10.4141/cjas85-098
The effects of zeranol were studied in 24 steers and 24 bulls starting at an average weight of 200 kg for a trial period of 183 days. Bulls grew faster than steers (P = 0.07) and zeranol-treated cattle showed higher average daily gain than controls (P < 0.05); there was no significant interaction between gender and treatment. Castration increased carcass fatness (P < 0.01) and decreased dressing percent (P < 0.01), rib-eye area (P < 0.01), shank muscle (P < 0.01) and shank muscle:bone ratio (P < 0.01). Implantation with zeranol had no effect on these traits. The weights of the radio-ulna, metacarpal and metatarsal bones were not significantly affected by gender or treatment. Growth at the distal end of the radius during the last 2 mo of the experiment was significantly less in treated cattle than in controls (P < 0.01) and in steers than in bulls (P < 0.01). Zeranol resulted in larger pelvic openings (P < 0.01) in bulls and steers and reduced libido (P < 0.05) in treated bulls.