Efeitos genéticos e ambientais para probabilidade de prenhez precoce em novilhas da raça Nelore

Abstract

The reproductive performance of females are considered of high importance for beef cattle, because the productivity of rural enterprises is directly linked to the number of animals born in the shortest time possible. Therefore, sexually precocious animals are desirable and have been the focus of genetic evaluation programs in Brazil. We used reproductive data from Nelore females born between 2014 and 2016 and belonging to the Agropecuária Jacarezinho, located in Cotegipe, Bahia, Brazil. Thus, the objectives of this work were to evaluate the environmental effects that act on the probability of precocious pregnancy and to use this information to estimate genetic parameters in Nellore cattle. Significant effects (p <0.05) were observed for year of birth, month of birth and farm of rearing that act on the probability of precocious pregnancy. The analysis for estimation of genetic parameters did not show convergence, because the data used come from a portion of the total information that the property has for this trait. There was a need for adjustment for environmental effects after statistical analysis. Future analyzes that consider databases with a larger set of animals may assist in the study of traits associated with the reproductive precocity of females through the estimation of genetic parameters.