Breeding and Genetics: Applications and Methods in Animal Breeding—Dairy I

The objective of this study was to analyze the correlation between Holstein body conformation traits and milk production traits in the Shanghai region. In total, 871 Holstein cows were randomly chosen from 28 dairy farms in Shanghai at second stage of lactation as the object of our study. Five milk production traits, including 305-d milk yield, butter fat percentage, milk protein percentage, peak lactation days and peak milk production were obtained from dairy Herd Improvement (DHI) project of Shanghai Dairy Breeding Center. The quantitative values of 7 body conformation traits were recorded by 9-point methods and the model of multiple linear regressions was used here to analyze the correlation between the body conformation traits (as independent variable) and the milk production traits (as dependent variable). The results showed that the total score of body conformation were extremely significantly positively correlated with the 305-d milk yield, butterfat percentage, Peak milk production (P < 0.01), significantly positively correlated with the peak lactation days (P < 0.05), and weak correlation with the milk protein percentage (not significant). The body hindquarters capacity was significantly positively correlated with the milk yield. The cow hoofs character was extremely significantly positively correlated with the peak milk production, the butterfat percentage, and the milk protein percentage; and was significantly positively correlated with milk yield. The hip character was significantly positively correlated with the butterfat percentage. The lactation system and udder traits were significantly positively correlated with the peak lactation days. We concluded that the body hindquarters capacity, the hoofs character, the hip character, the lactation system and udder traits were the most important factors that influenced the milk production traits of Holstein cows. The identification and scoring of body conformation traits might provide significant guiding on screening high-yield, excellent producing Holstein cows as well as selection and assortative mating.