Body condition related to ketosis and reproductive performance in Norwegian dairy cows.

The relationships between body condition score (BCS) and ketosis, and between BCS and reproductive performance in 732 moderate yielding, dual-purpose cows were studied. The cows were of the breed Norwegian Cattle. Farms with tie-stall barns and a history of high ketosis incidence were chosen for the study. Sixteen assessors visited the farms monthly and the same assessor assigned a BCS to each cow once a month. A BCS of 3.5 or higher at calving was associated with increased risk for ketosis. Cows that subsequently developed ketosis had higher BCS than healthy cows before the disease was diagnosed, and they lost more body condition than did the latter after ketosis had occurred. Summer calving cows and primiparous cows showed the lowest risk of ketosis. A history of ketosis before first service decreased the likelihood of conception to that service. Loss in body condition during the postpartum period was associated with decreased likelihood of conception to first service, prolonged calving to conception intervals and increased number of artificial inseminations per conception. Reproductive performance was not associated with BCS at calving. We concluded that BCS is a useful method of monitoring relations among nutritional management, reproduction, and ketosis in moderate yielding dual-purpose cows.