EVALUATION OF THE BENEFITS OF THE TIMING OF PREGNANCY TESTING BY TRANSRECTAL PALPATION IN DAIRY-CATTLE

Objective-To determine the benefits that were associated with pregnanc y testing by use of transrectal palpation during the period 30 to 65 d ays after unsuccessful insemination of dairy cows. Design-Nonconcurren t, cohort study. Animals-Cows in 15 dairy herds in the United States a nd Canada. Procedure-Reproductive records of cows (n = 713) that did n ot calve within 294 days of first-service insemination and that had be en evaluated for pregnancy 30 to 65 days after first-service inseminat ion were examined. Records were analyzed to determine the day of partu rition or date of culling and to determine if the probability of a cow being culled or the interval to parturition was related to the number of days after insemination that pregnancy testing was performed. Resu lts-For cows that carved more than 294 days after first-service insemi nation, the interval from first-service insemination until parturition was associated significantly with herd, season, and treatment on the day of pregnancy testing with prostaglandin F-2 alpha or one of its an alogues. Cows treated with prostaglandin F-2 alpha on the day of pregn ancy testing were less likely to be culled than nontreated cows. For c ows pregnancy tested 30 to 65 days after insemination, each additional day after day 30 before pregnancy testing was performed resulted in a n increase of 1.09 days in the interval until parturition. Clinical Im plications-Pregnancy testing by means of transrectal palpation as soon as possible after day 30 after insemination can result in shorter car ving intervals.