Abstract
The genetic trend for herd life of Holstein cows was predicted from direct and indirect genetic evaluations. Data consisted of herd life of 838,232 cows obtained from test day records between 1985 and 2002, and linear type records that were scored between 1997 and 2003. The genetic trend for herd life was estimated from direct genetic evaluations for bulls and their daughters that have already had a herd life record. Genetic evaluations of the cows without the record of herd life and their bulls were predicted indirectly from their type records using Best Prediction. Two models for indirect prediction were assumed. Two models that predict the evaluation of herd life with 14 type records (full model) and 8 type records (reduced model) were compared. If at least one parent of an animal has direct evaluation of herd life, their indirect information was combined with their parent’s direct evaluation. Heritability of herd life was 0.08. The correlations among direct and indirect estimations were 0.52 for the full model and 0.66 for the reduced model. The reduced model was better because their indirect predictions were closer to the direct estimations than those of full model. The cows had not been selected yet genetically for herd life in Japan. But, when the genetic trend was predicted from direct and indirect estimations using the reduced model, herd life estimations increased gradually.
