Genetic Parameter Estimation of Carcass Traits of Hanwoo Steers
2008
Hwang, J.M. (National Institute of Animal Science, RDA, Cheonan, Republic of Korea) | Kim, S.D. (National Institute of Animal Science, RDA, Cheonan, Republic of Korea), E-mail: goldstar@rda.go.kr | Choy, Y.H. (National Institute of Animal Science, RDA, Cheonan, Republic of Korea) | Yoon, H.B. (National Institute of Animal Science, RDA, Cheonan, Republic of Korea) | Park, C.J. (Livestock Service Department, National Agricultural Cooperative Federation, Seoul, Republic of Korea)
The genetic parameters used in National Hanwoo Genetic Evaluation (NHGE) were needed to be monitored and updated periodically for accounting any possible changes in population parameters due to selection and environmental changes. Genetic parameters were estimated with single and two-trait models with MTDFREML package using 2,791 carcass records of steers collected from Hanwoo Progeny Test Program (HPTP). Single and two-trait models gave similar parameter estimates for all traits. The heritability estimates from single and two-trait models for carcass weight (CW), dressing percentage (DP), eye muscle area (EMA), back fat thickness (BFT) and marbling score (MS) were 0.30, 0.30, 0.37, 0.44 and 0.44, respectively. The heritability estimates for all the traits except BFT were slightly lower than those used in NHGE but seemed to be within the acceptable ranges. However, further monitoring is needed because the data might not have fully reflected the changes such as carcass grading standards in performance testing program. In order to shift statistical model of NHGE from single trait model to multiple-trait model, the genetic correlations between carcass traits were estimated with pairwise two-trait models. The genetic correlation coefficients between CW and DP, between CW and EMA, between CW and BFT and between CW and MS were 0.44, 0.63, 0.17 and 0.06, respectively. Those between DP and EMA, between DP and BFT and between DP and MS were 0.29, 0.40 and 0.20. Those between EMA and BFT and between EMA and MS were -0.24 and 0.15, respectively. The genetic correlation coefficient between BFT and MS was 0.03.
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