Estimação de parâmetros genéticos para características produtivas em búfalos na Amaznia Oriental

Abstract

Data from 1,182 records of Murrah females buffaloes and their crossbreds, calving from 1967 to 2005, were used to estimate genetic parameters by maximum restricted likelihood method. An animal model used to estimate variance components, included the fixed effects of herds, year and season of calving, order of parity, and length of lactation as covariables; and random effects of animal, permanent, and temporary environment. The estimate of heritability to milk yield, fat yield, length of lactation, and milk yield per day of calving interval were 0.25, 0.18, 0.08, and 0.09 respectively. Estimate of repeatability for milk yield, fat yield, and length of lactation were 0.33, 0.29, and 0.10, respectively. The genetic correlations between milk yield and fat yield, milk yield and length of lactation, milk yield and milk yield per day of calving interval, fat yield and length of lactation, fat yield and milk yield per day of calving interval, and length of lactation and milk yield per day of calving interval were 0.93, 0.76, 0.99, 0.89, 0.87, and -0.27, respectively. These results showed that genetic gains may be obtained by selecting to milk and fat yields.