Performance, blood and carcase characteristics of finishing steers treated with trenbolone acetate and hexoestrol.

Twenty British Friesian steers were divided into four uniform groups and either not treated or implanted with hexoestrol, trenbolone acetate, or hexoestrol plus trenbolone acetate. Hexoestrol was given 90 days and trenbolone acetate 70 days, before slaughter. Animals in the treatment groups grew significantly faster, converted food to live-weight gain more effciently faster, converted food to live-weight gain more efficiently and had lower levels of plasma urea and to a lesser extent serum albumin than untreated controls for the final 70 days before slaughter. The combined treatment of hexoestrol plus trenbolone acetate produced more pronounced effects than either compound given alone. Steers treated with hexoestrol had significantly greater levels of serum growth hormone than steers implanted with trenbolone acetate alone or untreated controls, but the treatments had no significant effect on levels of plasma glucose, free fatty acids or serum insulin. Carcase conformation and fat cover assessed subjectively did not differ between treated and control animals but killing out percentage was generally higher in all treatment groups.