Comparison Between The Performance Of Nelore Females And Crossbred Females In Relation To Age At The First Calving And Birth Weight Of The Progenies In The Transition Region Of Cerrado-Amazon

Observations of 406 registers of bovine females were assessed with the aim of comparing the performance of Nelore females with crossbred females Caracu x Nelore in relation to birth weight (PN) of the product and age at first calving (IPP). The registers were from the farms Boa Esperan double dagger a and Paulista, located in the city of Sinop, Mato Grosso. For the birth weight, the model employed the fixed effects of the genetic group, sex of the product, farm, birth period, interactions between genetic group with sex, with farm and with birth period, besides the covariable of age at calving, and age at first calving. The model employed included the effects of the genetic group of the matrix, farm and period of calving. The average IPP was equal to 31.52 +/- 1.14 and, except for the effect of birth period, all other effects studied in the model were not significant (p>0.05). Regardless of the matrix genetic group, cows that gave birth during rainy seasons presented higher precocity for the first calving. Males coming from crossbred females were heavier in relation to females coming from Nelore females or crossbred that gave birth to females.