By Groen, A. F. and Hellinga, I. and Oldenbroek, J. K., Netherlands Journal of Agricultural Science, 1994
Description
Direct selection for decreased disease incidence is difficult given low heritabilities and absence of disease recording. Genetic correlations between diseases and type traits indicate possibilities for indirect selection; however, correlations often include experimentally instead stead of routinely scored type traits. The aim of this study was to estimate genetic correlations of clinical mastitis and feet and legs problems with milk yield and routinely scored type traits in Dutch Black and White cows. From 1983 to 1991, incidence of diseases was recorded at 44 farms with Dutch Black and White dairy cattle. In total, records on 3617 cows sired by 224 bulls were analyzed. Heritabilities for milk yield, type traits, and diseases were obtained using an equal design multi-variate REML procedure considering all observations on a continuous scale. A bivariate threshold procedure was used to estimate heritabilities for diseases and genetic correlations of diseases with milk yield and type traits. Genetic correlations of clinical mastitis and feet and legs problems with milk yield were unfavorable (0.16, 0.26), and heritabilities for diseases were low (0.01-0.11). Unexpected positive relations between udder type traits and clinical mastitis were found (0.09-0.26), and possible reasons were discussed. Genetic correlations between type traits for feet and legs and feet and legs problems were negative (-0.01, -0.24). Final score for feet and legs might be used as selection criteria to select for lower incidence of feet and legs problems
Direct selection for decreased disease incidence is difficult given low heritabilities and absence of disease recording. Genetic correlations between diseases and type traits indicate possibilities for indirect selection; however, correlations often include experimentally instead stead of routinely scored type traits. The aim of this study was to estimate genetic correlations of clinical mastitis and feet and legs problems with milk yield and routinely scored type traits in Dutch Black and White cows. From 1983 to 1991, incidence of diseases was recorded at 44 farms with Dutch Black and White dairy cattle. In total, records on 3617 cows sired by 224 bulls were analyzed. Heritabilities for milk yield, type traits, and diseases were obtained using an equal design multi-variate REML procedure considering all observations on a continuous scale. A bivariate threshold procedure was used to estimate heritabilities for diseases and genetic correlations of diseases with milk yield and type traits. Genetic correlations of clinical mastitis and feet and legs problems with milk yield were unfavorable (0.16, 0.26), and heritabilities for diseases were low (0.01-0.11). Unexpected positive relations between udder type traits and clinical mastitis were found (0.09-0.26), and possible reasons were discussed. Genetic correlations between type traits for feet and legs and feet and legs problems were negative (-0.01, -0.24). Final score for feet and legs might be used as selection criteria to select for lower incidence of feet and legs problems
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