Application of the Bovine Milk Pregnancy ELISA in beef cows

Abstract

Pregnancy-associated glycoproteins (PAGs) are produced by binucleate giant cells of the ruminant placenta and secreted into maternal circulation during pregnancy. These proteins can be detected in maternal serum and milk as early as 28 days post-insemination, which makes them a potential target for pregnancy detection, which in turn could provide an alternative management tool for dairy and beef producers. The presence of PA Gs in serum has been used extensively to diagnose bovine pregnancy. More recently, the Bovine Pregnancy ELISA (IDEXX, Westbrook ME) has been used to detect the presence of PAGs in milk. Although the milk ELISA was designed primarily to be a management tool for dairy operations, it has potential for use in beef operations in remote areas where veterinarians are not readily available to perform pregnancy diagnosis and the producer lacks the skill set to collect a blood sample. The objective of this study was to compare the results of the PAG ELISA used on milk and serum to pregnancy diagnosis by transrectal palpation or ultrasound in lactating beef cows with previous artificial inseminations or bull exposure.