Growth modeling of castrated Brahman males raised in tropical conditions and born in different seasons

Abstract

J.A. Miguel, S.J. Melendez, B. Asenjo, L.M. Bonilla, and J. Ciria. 2012.Growth modeling in castrated Brahman males raised in tropical conditionsdepending on the time of birth. Cien. Inv. Agr. 39(2): 279-288. In thispaper, parameters that describe growth, as a function of the season inwhich they were born (dry or rainy), are presented for males of the formales of the Brahman breed that were castrated at birth and raised intheir native environment in the intense system of the Llano Venezolano.Data are presented for 1,478 Brahman males that were castrated at birth.Of these, 750 were born in the months of June and July (the rainyseason) and 728 were born in January and February (the dry season). Theanimals born during the dry season were heavier up until the beginningof the fattening period; after weaning, the greatest average dailyweight gain coincided in both groups during rainy periods when thepasture production was greater. When comparing the observed weights withthe estimates, the Brody model was better at estimating the actualweight of the animals at birth, weaning and maturity in both seasons ofbirth. The Gompertz, Bertalanffy, Richards and Logistic modelsoverestimated the weights of the animals at birth and at the end of thefattening period; however, they underestimated the weights at weaningand maturity for both birth seasons. Regarding the birth season, nodifferences were found in the estimated maturation rate for any of themodels, although there were differences among the models for the sameseason of birth.