Submitted to: Journal of Animal Science Supplement
Publication Type: Abstract Only
Publication Acceptance Date: March 30, 2001
Publication Date: December 20, 2001
Citation: Vallet, J.L. 2001. The influence of uterine function on embryonic and fetal survival [abstract]. Journal of Animal Science. 79(Supplement 1):230-231. (Abstract No. 954) Technical Abstract: The secretion rate of growth factors and the delivery rate of nutrients by the uterus affects the growth rate, development and survival of the conceptus. Transport of some nutrients is aided by specific transporter molecules on the uterine endometrial epithelial cell, while others (e.g., retinol, iron, folate) are incorporated into uterine secreted proteins (e.g., retinol binding protein, uteroferrin, folate binding protein). The rate of production of these proteins during pregnancy profoundly affects pregnancy outcome. Uterine gland knockout experiments in sheep demonstrate that pregnancy fails in the absence of uterine glands. In pigs, both global and specific effects of uterine products on aspects of conceptus development can influence litter size. For example, the uterus of the Meishan pig secretes less protein prior to elongation, which slows conceptus development, results in smaller placentas and smaller fetuses, and allows for greater litter size. Furthermore, in Occidental pig breeds, an earlier rise in progesterone at the beginning of pregnancy accelerates the onset of protein secretion, increases estrogen secretion by the conceptus, increases the size of the fetus in later pregnancy, and decreases litter size. Specific uterine products (uteroferrin, folate binding protein) are required for all fetal erythropoiesis and greater litter size is associated with improved erythropoiesis. Thus, manipulation of uterine function can impact pregnancy success in domestic livestock.