Genetic parameters and trends of cow livability in Holsteins in Hokkaido, Japan
2020
Abe, H. (Hokkaido Dairy Milk Recording and Testing Association, Sapporo (Japan)) | Hagiya, K. | Yamaguchi, S. | Nakagawa, S. | Gotoh, Y. | Baba, T. | Kawahara, T.
We applied a threshold animal model and linear animal model to a new longevity trait, cow livability (CL), and 1) estimated genetic parameters ; 2) estimated breeding values and analyzed their genetic trends ; and 3) determined the applicability of CL to traits for selection. We included stayability (STAY) in the analysis for comparison with CL. The heritability estimates of CL were less than 0.1, and the estimated genetic correlations with STAY at the same parity were between 0.70 and 0.84. High genetic correlations (0.81 to 0.96) were estimated in an across-parity analysis using the threshold model. The correlations of estimated breeding values for the same trait in first parity between the linear and threshold models were 0.97 or more. Analysis of the genetic trends of CL and STAY indicated a decline in EBVs with increasing birth year. Selection for CL at first parity may help to improve the genetic progress of CL in later parities.
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