Comparison between the effects of zilpaterol hydrochloride and Rsalbutamol during the finishing period on the growth performance and carcass characteristics of feedlot cattle

Abstract

This study was conducted on 228 typical South African feedlot steers, of which 114 steers were fed 60 mg of zilpaterol HCl per steer per day for the final 30 days of the feedlot finishing period and the other 114 steers were fed 120 mg of R-salbutamol per steer per day for the last 30 days of the feedlot finishing period. The animals were slaughtered at the same abattoir after waiting the 3-day withdrawal period of zilpaterol HCl and R-salbutamol. The recorded growth and feedlot parameters included starting weight, slaughter weight, average daily gain, live weight gain and lean gain. The recorded carcass and meat characteristics parameters included warm and cold carcass weights, carcass length, carcass fat thickness measured over the 13th rib, carcass classification score, age code as well as fat code using the current South African classification system, dressing percentage, and carcass compactness.