Document Type : Research Paper
Former M.Sc. Student, Department of Animal Science, Faculty of Agriculture, Isfahan University of Technology, Iran
Assistant Professor, Department of Animal Science, Faculty of Agriculture, Isfahan University of Technology, Iran
Associated Professor, Department of Animal Science, College of Agriculture, Shiraz University, Iran
Genetic and phenotypic parameters for the first three lactations profitability and sum of first three lactations as lifetime profitability in Iranian Holstein cows were estimated, using data of 86,065 cows in 423 herds, from 2000 to 2011 collected by the Animal Breeding Centre of Iran (ABCI). Economic data were collected from three large dairy farms in Isfahan province. Estimates were performed by using bivariate animal model through the VCE.6.2 software. Estimated heritabilities were moderate and ranged from 0.14 (for third lactation profitability) to 0.32 (for lifetime profitability). Estimated genetic correlations were close to one and ranged from 0.88 between first and third lactation profitability to 0.99 between second lactation profitability and lifetime profitability. Phenotypic correlations were high and in the range of 0.38 between first and third lactation profitability to 0.82 between second lactation profitability and lifetime. Genetic and phenotypic correlations between first lactation and lifetime profitability were 0.96 and 0.76, respectively. These high values of correlations and heritabilities obtained for the first lactation profitability (0.31) showed that the profitability of the first lactation might be a good predictor of lifetime profitability. Therefore, by direct selection on first lactation profitability, genetic-economic merit could be improved.