Relationship between body condition scores and milk yield in a large dairy herd of high yielding Holstein cows.

This study investigated the relationship between body condition and milk yield of dairy cows. Holstein cows (n = 779) on a commercial dairy farm were scored for body condition weekly beginning at dry-off and continuing until 120 d of lactation. Multiple linear regression and principal component analysis were used to characterize relationships. Mean body condition scores were 2.77 and 2.66 at dry-off and parturition, respectively. Principal component analysis was used to reduce the collinearity among independent variables, to calculate new parameter estimates, and to rank the relationship of each variable with milk yield. Results indicated that change in body condition during the dry period was ranked first, followed by lactation number, and then body condition score at dry-off for multiparous cows. A one-point increase in body condition score between dry-off and parturition was associated with 545.5 kg more milk in the first 120 d of lactation. Each additional point of body condition at dry-off was associated with 300 kg less milk at 120 d of lactation. Results suggested that cows that gained condition during the dry period yielded more milk in the first 120 d of lactation and had an accelerated rate of increase in milk yield. The results of this study indicate that body condition score is an important tool for monitoring dairy herds.