Effect of Dam Body Conformations on Birth Traits of Calves in Chinese Holsteins

SIMPLE SUMMARY: The birth traits of calves are directly related to the economic benefits of the dairy farm. Predicting the birth traits of calves before they are born will benefit the breeding of cows and reduce the potential loss of pasture. Conformation traits are closely related to the reproduction of dairy cows. The objective of the present study was to examine the associations among birth traits and conformation traits in Chinese Holstein dairy cows, in order to provide a reference for understanding the birth traits of calves in advance by using the conformational traits of dam cows. In this study, we analyzed the relationship between female structure traits and calf birth traits by logistic regression and multiple comparisons. We found that there was a significant correlation between the two, which could predict the birth traits of calves to a certain extent by the body conformation traits of dams. ABSTRACT: The objective of this study was to explore the effect of dam body conformations on birth traits including stillbirth, dystocia, gestation length and birth weight of Chinese Holstein calves and to provide a reference for improving cow reproductive performance. We collected phenotype data on 20 conformation traits of Chinese Holstein cows and analyzed the impact of dam conformation trait linear scores on stillbirth, dystocia, gestation length and calf birth weight. The feet angle, set of rear legs, fore udder attachment and rear attachment height traits of the dairy cows significantly affected the risk of stillbirth. The risk of dystocia decreases with the increase in stature and pin width. The bone quality of dairy cows had a significant positive correlation with gestation length. There was a significant positive correlation between fore udder attachment and calf weight at birth. The birth weight of calves from cows with high body conformation traits was significantly higher than that of calves with a low composite score. These results suggest that improving the body conformation traits, especially the selection of mammary system and body shape total score, will be beneficial in improving the reproductive performance of dairy cows.