Estimación de factores de ajuste para el peso y la edad en hembras de la raza Carora

Fifty-eight thousand eight hundred ans sixty two weights taken from 12,081 females were analyzed from the Carora breed aging from 30 to 2,500 days to obtain the adjustment coefficients of the weight for the age and the age for the weight. To analyze the weight, a mix animal model has been adapted which included the fix effect of the age grouped into 244 classes of 10 days each, meanwhile, for the analysis of the age in the model the weights grouped into 14 classes of 50 kg each were introduced. The curves of the weight and the age was calculated based on the estimated means of the factors “type of age” by the weight and the factor “type of weight” for the age, obtained from both models. The two curves explained with a high determination coefficient the variability of both the weight (R2=0.994) and the age (R2=0.992). The cow reaches the mature weight from 67 to 75 months of age, that is, the third and fourth lactation. The use of these coefficients would allow the breeders to foresee the age when a heifer that belongs to a determine type of weight, reaches the typical weight for the service and obtain information about the precocity.