RESUMEN
The objective was to estimate genetic correlations between body weight (BW), scrotal circumference and visual evaluation scores of body conformation measured at standard ages in Guzerat cattle. All measurements were performed at 205 (weaning age), 365, 450 and 550 days of age; for BW, two additional measurements (at birth and 120 days of age) were realized. The data utilized in this study were retrieved from a database of the Brazilian Association of Zebu Breeders that contained information of registered Guzerat animals born between 1970 and 2013. Genetic parameters were estimated in bi-trait analyses by using Bayesian inference. Genetic correlations between BW at 205 and 450 days of age with other traits were high and positive, whereas the correlations between visual evaluation scores with other traits were moderate. Based on correlations herein obtained, we conclude that selection based on BW results in increased visual scores and scrotal circumference, leading to improvements in productive performance and animals with best body conformation.
Asunto(s)
Constitución Corporal/genética , Peso Corporal/genética , Bovinos/anatomía & histología , Bovinos/genética , Estudios de Asociación Genética , Escroto/anatomía & histología , Animales , Teorema de Bayes , Bovinos/crecimiento & desarrollo , Masculino , Carácter Cuantitativo HeredableRESUMEN
Our objective was to evaluate carcass and meat characteristics of Guzerat-crossbred bulls finished in feedlot. Carcasses from 18 bulls, randomly selected from a larger group of 36 bulls, consisting of F1 Guzerat×Holstein ("Guzholstein"); F1 Guzerat×Nellore ("Guzonell"); and 1/2 Simmental+1/4 Guzerat+1/4 Nellore (Three-Cross; n=6 each group) were used. Cold carcass weight was greater (P=0.01) for Three-Cross compared with "Guzonell" and "Guzholstein". Three-Cross carcasses had greater (P<0.01) rib-eye-area and 100-kg-adjusted rib-eye-area among groups. Longissimus lumborum length did not differ (P>0.05) among groups, but depth was greater (P<0.01) for Three-Cross compared with other groups. "Guzholtein" had lesser (P=0.05) shear force compared with "Guzonell", with Three-Cross being intermediate. We conclude that "Guzholstein" is an adequate option for producers willing to finish this kind of genetic group, as it is comparable or better than Bos indicus crosses and B. indicus×Bos taurus bulls.
