Utilizing Pregnancy Associated Glycoproteins to improve reproductive efficiency in cattle

Diagnosing and maintaining successful pregnancies are one of the most important components to profitable and efficient management of beef and dairy cattle operations. Pregnancy loss is a major component of reproductive inefficiency and has been investigated less intensively in beef cattle than in dairy cattle. Pregnancy Associate Glycoproteins [PAGs] are placental products which have been identified as an accurate tool for pregnancy diagnosis and as substantial evidence indicates, markers of embryo and placental competence. The aim of these two studies is to further distinguish characteristics of pregnancies based on PAG concentration. Serial embryo transfer was used in beef heifers to asses PAG concentrations of heifers of varying fertility status. There was no difference in PAG concentration between high or subfertility heifers. However, heifers which maintained pregnancy until day 60 of gestation had an increased PAG concentration compared to those that lost pregnancy between day 28 and 60 (P=0.051). The second study examined the use of PAG concentration at day 24 of gestation as a tool for early gestation pregnancy diagnosis in Holstein dairy heifers carrying in vitro produced embryos. Circulating PAG concentration at day 24 was increased in animals that were pregnant compared to animals that were not; however, pregnancy maintenance could not be determined based on day 24 PAG concentration. Early gestation pregnancy diagnosis using PAG may be a viable option with more data and possible assay refinement for specific PAGs.