Body condition scores of Holstein cows on Prince Edward Island, Canada: relationships with yield, reproductive performance, and disease.

An observational study of 429 Holstein cows in 13 herds (mean 305-FCM yield of 7225 kg) was conducted to determine the relationship between body condition score and its changes with milk yield, reproductive performance, and disease incidence. Cows were scored once for body condition during the dry period, near calving, and then every 14 d until termination of lactation. Condition score at calving had no effect on either peak of 305-d milk yields. Condition loss averaged .73 and .83 points for primiparous and multiparous cows, respectively. The duration and magnitude of condition loss depended primarily on score at calving and was greater for cows that calved with higher condition scores. After reaching minimum score, cows gained an average of .53 condition points in the remainder of lactation. Total amount of gain was not affected by body condition score at calving or by milk yield. No significant differences were found for days to first observed estrus, days to first breeding, days to conception, or number of times bred for cows grouped by body condition score at calving or by condition loss between calving and first breeding. Body condition score at calving was not significantly different for diseased cows. Cows that were diagnosed with a disease lost more condition than undiseased cows, but the difference generally was < .25 points.