Confirmation of estrus rates by palpation per rectum of genital organs in normal repeat dairy cows.

Data were from 6084 normal repeat to second service cows, visually detected in estrus, in a commercial artificial insemination program on a.m./p.m. schedule. The percentage of cows confirmed in estrus by rectal examination and inseminated after palpation was 96.2. The remainder of the cows were not inseminated and non-return rate for these cows was 86.9% (150-day non-return). In cows confirmed in estrus, the percentage of cows ready for service at palpation was 96.1 and the 150-day non-return percentage for these cows (43.9) was different from those cows in which estrus and insemination were considered incorrectly timed (26.7%). These results suggest that the efficiency of reproduction in dairy herds may be improved by examination per rectum of the genital organs at insemination as an effective complement to visual detection of estrus.