Growth curve, carcass traits and Kleiber ratio of Dorper crossbreed with hairless native Brazilian sheep breeds

In Brazil, much of the sheep farming is practiced with native breeds or crossbred with specialized breeds. The market is growing and to serve consumers it is necessary to regularly provide quality meat. Rearing these animals with lower production costs can be achieved using feed efficiency and growth information, useful to define the most appropriate crossbreed for both farm structures and breeder's objectives. Thus, the objective of the present work was to evaluate the growth, carcass traits and Kleiber ratio (KR) of, respectively, 44 and 39 animals slaughtered at 120 (120D) and 240 days (240D) of the following crosses: Dorper x Morada Nova females and males (F_DMN, M_DMN), Dorper x Santa Ines females and males (F_DSI, M_DSI), and Dorper x Rabo Largo females and males (F_DRL, M_DRL). The traits evaluated were: the weight of the rib, loin, left half carcass, shoulder, leg, Longissimus Dorsi muscle area (LDM), growth curve and KR. Univariate and multivariate analyses were used, and it was observed, at 120D, that DSI and M_DRL had higher cut weights. There was the superiority of the M_DSI in relation to the others for the cuts rib, loin (excerpt with DRL that was similar), half carcass and shoulder at 240D. At 240D all crossbreeds have a value greater than 100 % of the percentage of their asymptotic weight, except the M_DSI. At 240D the animals tended to lower values of KR compared to 120D. Differences were observed between the crosses considering the variables simultaneously. In the grouping at 120D, an approximation between DSI and M_DRL was observed. The DMN at 240D, have lower values for carcass traits and growth and superiority for KR and degree of maturity. The M_DRL with F_DRL and F_DSI were characterized as intermediate for growth, carcass, and KR. In PCA1 at 120D, most of the explanation for differentiating crosses are concentrated in meat cuts. At 240D again, the carcasses contributed to differentiate the crosses, however sharing with the parameters of growth. It is concluded that animals should be slaughtered before 240D. If it is used to slaughter 120D, the cattle rancher can choose, when economically feasible, to slaughter animals regardless of sex and crossing, however, the farmers must be attentive only to prioritize the DSI and M_DRL as an alternative to serving the consumer market that prefers heavier cuts.