Use of Chemical Tests for Pregnancy Diagnosis in a Reproductive Management Program

Early identification of nonpregnant dairy cows post breeding can improve reproductive efficiency and pregnancy rate by decreasing the interval between AI services and increasing AI service rate. Thus, new technologies to identify nonpregnant dairy cows early after artificial insemination (AI) may play a key role in systematic management strategies to improve reproductive efficiency and profitability on commercial dairy farms. Transrectal palpation is the oldest and most widely used method for early nonpregnancy diagnosis in dairy cattle (Cowie, 1948); however, a newer technology may emerge to replace transrectal palpation as the method of choice for nonpregnancy diagnosis in the dairy industry. One such technology is the development of commercially available tests to detect pregnancy-associated glycoproteins (PAGs) in maternal serum; however, this new technology must be practically integrated into a systematic on-farm reproductive management strategy for it to succeed. Research reviewed in this paper support use of PAGs as a method for early nonpregnacy diagnosis in dairy cattle; however, there are some caveats and limitations with regard to their incorporation into a systematic reproductive management program that must be considered to determine the appropriate timing of nonpregnancy diagnosis.