Optimal time postbreeding for pregnancy examination in dairy cattle.

The objective of this study was to determine the relationship between calving interval and the interval from artificial insemination to pregnancy examination. Cows examined for pregnancy at 30 or more days postbreeding were followed to determine the calving interval for cows examined at sequential intervals postbreeding (e.g. 42-44 days, 45-47 days postbreeding). Cows included in the study were from five large dairies in California, were presented for pregnancy examination from December of 1982 to April of 1983, and had a calving interval of from 290 to 530 days. All palpations were done by one of two experienced veterinarians. Calving intervals were significantly lower for cows pregnancy examined from 51-56 days postbreeding than for cows examined earlier or later.