Sync Programs and Ultrasound

Are We Getting in There too Early?

Abstract

Early identification of non-pregnant dairy cows and heifers post-breeding can improve reproductive efficiency and pregnancy rate by decreasing the interval between artificial insemination (AI) services and increasing AI service rate. Thus, new technologies to identify non-pregnant dairy cows and heifers early after AI may play a key role in management strategies to improve reproductive efficiency and profitability on commercial dairy farms. Transrectal palpation is the oldest and most widely used method for early pregnancy diagnosis in dairy cattle7 • However, a newer technology may someday replace transrectal palpation as the method of choice for pregnancy diagnosis in the dairy industry. Before this transition can occur, two events must transpire. First, a technology must be developed that exceeds transrectal palpation in one or more of the characteristics of the ideal early pregnancy test. Second and no less important, this new technology must be practically integrated into a systematic, on-farm reproductive management strategy and empirically demonstrated to exceed the status quo of the industry (i.e., transrectal palpation) in reproductive performance. Results from a recent study indicate that positive pregnancy outcomes diagnosed by transrectal ultrasonography conducted 26 days after timed AI (TAI) may be inflated due to pregnancy loss, compared to pregnancy outcomes conducted 33 days after TAI. Furthermore, fertility to TAI after re-sychronization of ovulation was greater when initiated 33 days after TAI compared to 26 days. These results suggest the counterintuitive notion that delaying pregnancy diagnosis from 26 to 33 days post-TAI may improve reproductive efficiency when using a hormonal protocol for timed AI to program non-pregnant cows for rebreeding. This is due to the high rate of pregnancy loss occurring in cows diagnosed pregnant at 26 versus 33 days post-TAI.