Relative growth of body components from different zebu breeds

Abstract

Sixty three steers from zebu breeds Gyr, Guzerat, Mocho Tabapua and Nellore, weighing, respectively, 376.4, 357.6, 362.0 and 368.6 kg initial live weight and twenty-four months old, were used. The animals from each breed were divided into five groups. One group was ramdomly assigned to immediate slaughter (AB), three groups were full-fed a ration containing 50% concentrate, dry matter basis until reaching the slaughter weights of 405, 450 and 495 kg, respectively (group I, II and III). The fifth group was fed a restricted amount of the same ration (AR). At slaughter the empty body weight (EBW) was determined and the weight of internal organs and viscera were recorded. Regression equations of log weight of body component as a function of log EBW were fitted. All body components studied, with exception of liver and spleen, developed slowlier than EBW.