The aims of this research were to determine economic selection indices in order to reach the target objective for a Caracu cattle nucleus. The breeding objective (H) considered a dual purpose breed producing milk and weaning calves. The biological traits affecting income and expenses considered in H were: total milk yield, age at first calving, number of days open, weaning weight, and productive lifetime. Two economic selection indices were calculated. The selection criteria included in Index 1 were first lactation milk yield, number of days open from first to second calving, scrotal circumference adjusted to age and weight at 15 months and weaning weight (WW). Index 2 included the same traits but WW was switched by average daily gain from birth to weaning. The statistical analyses to estimate the (co)variances and genetic and phenotypic parameters were performed by derivative-free restricted maximum likelihood method, using an animal model (uni and bi-trait). Records on animal performances, pedigrees and prices were provided by the breeder. The production costs and revenues of this herd were calculated from 1994 to 2000. The profit equation was set to an annual base using annual averages for number of animals per category, biological traits and prices. The economic value of each trait was obtained as the partial derivative of the profit function with respect to that trait (evaluated at the average for all other traits). Both indexes would improve selection response to H, but the economic selection index 1, including WW, would be a little more efficient for total selection response to H.
dual purpose breed; economic selection index; economic value; genetic gain
