GEVREKÇİ, Yakut Ege Üniversitesi - Ziraat Fakültesi - Zootekni Bölümü, Turkey , AKBAŞ, Yavuz Ege Üniversitesi - Ziraat Fakültesi - Zootekni Bölümü, Turkey

Calving Ease Analysis as a Threshold Trait

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This study was conducted to estimate genetic parameters of calving ease as threshold traits. In this research, calving ease scores with four categories obtained from 404460 animals in the first 6 lactations raised between 200-2005 years in 3980 Holstein herds in United States.In the analysis, Gibbs Sampling method is used. This method uses posterior density combining by prior densities and likelihood for the traits. Variance components, heritabilities and genetic correlations between direct and maternal genetic components were estimated by using Sire+Maternal grandsire model. Direct and maternal heritability estimates for calving ease were 0.06 and 0.04, respectively. Genetic correlation between direct and maternal effects was low and negative. In conclusion, because of maternal genetic effects contribution to the models, Sire+Maternal grandsire model is recommended for analyzing calving ease.

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Threshold Traits , Calving Ease , Gibbs Sampling , Genetic Parameters

The Journal Of Ege University Faculty Of Agriculture

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