EMBRYO MORTALITY ENTAILS A MASSIVE IMMUNE RESPONSE IN DAIRY COWS

Although general predisposing factors for poor fertility in the modern Holstein cow have been identified, the biological mechanisms underlying early embryo mortality in ruminants are not completely understood. Further improvements in reproduction of ruminants require a better understanding of establishment of pregnancy such that strategies can be devised to mitigate the incidence of early embryo mortality. Early embryo mortality pregnancies in dairy cows cause an annual economic and productivity loss of $1.6 billion-dollars in the USA. This economic loss is mainly due to inefficient management of nonpregnant cows with pregnancy failure caused by early embryo mortality. Clarifying why early embryo mortality occurs may lead to identification of genetic biomarkers in cows that can be used to identify which animals are prone to have a pregnancy associated with early embryo mortality to facilitate selecting against them. Currently, studies are limiting that have explored the relationship between conceptus signalling and immune responses, conceptus morphology (normal or early embryo mortality) and maternal responses/environment (immune system) to pregnancy. Through discovery of single nucleotide polymorphisms that are related to a normal or early embryo mortality pregnancy, producers can select cows that are reproductively efficient and eliminate those that are not.Aim 1. Determine if early embryo mortality and impaired interferon tau production from the conceptus causes luteolytic endometrial signaling and activated inflammatory and luteolytic responses in the corpus luteum. Aim 2. Identify single nucleotide polymorphism markers in candidate genes that can predict normal compared to early embryo mortality pregnancies.