An Estimation of Discounted Genetic Expressions of Dairy Traits in Iranian Holstein Herds

The objective of this study was to assess the Discounted Genetic Expressions (DGEs) for different categories of animal traits as regards Holstein cattle of Iran. Using discounted gene-flow principles, DGEs per calf born were estimated for self replacing females and also for their sires. In the situation for sires of self replacing females, relative GDEs per cow per year for annual cow traits, traits of the calf at birth and slaughter, traits of heifer and traits of cow at culling were estimated as 1, 0.96, 0.4, 0.44 and 0.43, respectively. The respective values for self replacing females were 1, 0.5, 0.21, 0.44 and 0.43, respectively. The effects of different factors on DGEs were quantified using sensitivity analysis. Results obtained in this study provide important information for properly weighting the traits in national selection indexes and as well in conducting cost- benefit analyses of breeding strategies.