Non-inferiority trial of two commercial zilpaterol HCl brands in Bos indicus cattle under humid tropical conditions

Abstract

Commercial availability of a generic zilpaterol HCl (ZH) premix preparation for beef cattle in Mexico motivated a non-inferiority trial vs the reference preparation. The trial was conducted on zebu-type cattle (Bos indicus) under humid tropical conditions. Meat production and basic meat quality were assessed for 810 zebu bulls, aged 18-22 months and weighing 430 to 490 kg. Bulls were randomly assigned into one of three groups: ZHg, treated with the generic ZH (Zipamix®) preparation; ZHr, treated with the reference ZH (Zilmax®) preparation, and Cg, the untreated control group. Housing, shade surface, feeding and water availability were highly homogeneous between the animals’ pens. Results for the measured productive and meat quality parameters showed that both ZH-treated groups had higher values than the Cg (P < 0.05), and differences between the ZHg and ZHr groups were not statistically significant, thus fulfilling the criteria of a non-inferior ZH preparation. In this assay, ZH supplementation did not modify the amounts of moisture, fat, protein or ash in the Longissimus dorsi muscle compared with the meat from non-supplemented animals, and the overall meat acceptability was unaffected (P > 0.05).