Using heterospecific embryo transfer to study conceptus:uterine interactions in large bovids

The Program Area Priority addressed in this project is Animal Reproduction--Embryonic and fetal development (including interaction between the conceptus and its uterine environment). The overall objective of this sabbatical grant is to improve our understanding of the complex signaling that occurs between the conceptus and the uterus which is critical for the maintenance of pregnancy. Heterospecific embryo transfer (HET) will be used as a tool to explore how defects in signaling result in pregnancy loss. Cattle and bison have been chosen for these studies because of their close phylogenetic relationship and their economic significance to American agriculture. Pregnancy-associated glycoproteins (PAGs) have been chosen as indicators of conceptus:uterine signaling since they are secreted through an interaction of conceptus and maternal components of the placenta. PAGs can be reliably detected in the bloodstream of cattle after 35 days of gestation and our recent work suggests that the same is true for bison. The specific objectives of this sabbatical grant are 1) to develop a heterospecific (bovine:bison) embryo transfer model that can be used to study defects in conceptus-maternal signalling and 2) to characterize PAG genes and their temporal pattern of expression in bison. These are the essential first steps in accomplishing the overall objectives described above. This sabbatical will give Dr. Silvia the embryo transfer and molecular biological skills necessary to conduct and oversee this line of research in the future.