Parâmetros genéticos de características produtivas em bovinos de corte da raça Tabapuã criados na Amazônia brasileira.

Abstract

Cattle farming in the Legal Amazon has advanced in recent years, gaining prominence in the national productive scenario of bovine activity. The zebu breed, Tabapuã, included in the meat production contingent in the region, also stood out, due to its good adaptability in tropical regions and productive and reproductive precocity. However, knowledge about the genetics of this breed is still subtle in the Legal Amazon, requiring further work on the breed in the region in order to select the best animals in a genetic improvement program. Thus, the aim of this study was to estimate the genetic parameters of Tabapuã cattle with standardized weights at 205 (W205), 365 (W365) and 550 (W550) days of age. To estimate the genetic parameters of the animals, data on the growth of Tabapuã cattle from the Brazilian Association of Zebu Breeders (ABCZ), raised on pasture, were used. 91,992 data were used on Tabapuã animals belonging to the Legal Amazon, referring to the states of Amazonas, Mato Grosso, Maranhão, Rondônia, Pará and Tocantins. For systematic effects, contemporary groups (CG) that contained information on year of birth, season of birth (divided into rainy and less rainy season) and farm were included. Cow age at calving (CVI) was included as a linear and quadratic effect in the model. For the estimation of the variance components, the Bayesian method was used, using the Markov chain via Monte Carlo (MCMC) by the Gibbs Sampling method, executed through the F90 family program (BLUPF90). The direct additive heritability (ℎ𝑑2) for traits W205, W365 and W550 days of age were 0.15, 0.32 and 0.47, respectively. For maternal additive heritability (ℎ𝑚 2), the W205 trait was 0.05. Additive genetic correlations were moderate to high between weight pairs, greater than 0.47, indicating a high degree of association between P365550 traits. The estimated ℎ𝑑 2 values ranged from low to high for the traits evaluated by the Bayesian method. Therefore, there was genetic variability in animals of the Tabapuã breed, which suggests genetic gain through selection. In addition to correlated response between the characteristics.