| Abstract: | Genetic parameters for the prevalence of abomasal displacement and for milk yield traits were estimated using a data set of 3578 cows. The animals originated from 50 farms near Hanover being under the official milk recording scheme. At these farms all cases of abomasal displacement in German Holsteins were registered from July 2001 to January 2003. Using REML heritability estimates in linear animal models were h2 = 0.034 +/- 0.014, h2 = 0.017 +/- 0.013 and h2 = 0.029 +/- 0.011 for all cases of abomasal displacement, leftsided abomasal displacement and rightsided abomasal displacement, respectively. Additive genetic correlations between all cases of abomasal displacement and milk yield traits were small, ranging from rg = -0.20 (fat content) to rg = 0.08 (milk kg). However, there was a highly positive additive genetic correlation between leftsided abomasal displacement and milk yield of rg = 0.683 +/- 0.227. Leftsided abomasal displacement was correlated additive genetically to fat and protein yield, fat and protein content with rg = 0.595 +/- 0.297, r9 = 0.653 +/- 0.250, rg = -0.768 +/- 0.3280 und rg = -0.643 +/- 0.354, respectively. The additive genetic correlation to the ratio between fat and protein content was rg = -0.585 +/- 0.470. For rightsided abomasal displacement, additive genetic correlations were of similar size but with reversed signs. The estimates obtained for the residual correlations were negligibly small throughout. |
