title: The role of altered uterine-embryo synchrony on conceptus growth in the pig.
abstract: This study was conducted to determine whether inducing an embryo-uterine asynchrony during the preimplantation period would alter fetal and(or) placental size at term. Yorkshire gilts (n = 24) were checked twice daily for estrus and bred to a Yorkshire boar 24 h after the first exhibition of estrus. Embryos (1 to 4 cells) were flushed from the oviducts of each donor gilt on d 2.5 of gestation and transferred in equal numbers to the oviducts of a recipient gilt on d 1.5, 2.5, or 3.5 of the estrous cycle. Gilts were slaughtered on d 112 of gestation (calculated on the age of the conceptus) and fetal and placental weight, placental surface area, and implantation site lengths were determined. Although litter sizes were similar (9.1+/-0.9), conceptuses transferred to d 3.5 recipients became heavier fetuses (1.44+/-0.05 vs 1.23+/-0.04 kg, P < 0.001), with larger placental surface areas (1,793+/-60 vs 1,459+/-43 cm2, P < 0.01), and longer implantation sites (32.1+/-1.5 vs 24.9+/-0.6 cm, P < 0.001) than those transferred to recipients on d 2.5. These data demonstrate that oviductal transfer of embryos into a reproductive tract that is more advanced by as little as 24 h can result in alterations in placental growth and function during gestation.
authors.affiliation: Department of Animal Science, Iowa State University, Ames 50011, USA.
authors.forename: M E
authors.initials: ME
authors.lastname: Wilson
authors.forename: K A
authors.initials: KA
authors.lastname: Vonnahme
authors.forename: S P
authors.initials: SP
authors.lastname: Ford
mesh_terms: D000818:Animals; D004624:Embryo Transfer / Q000662:veterinary; D005314:Embryonic and Fetal Development; D004971:Estrus; D005260:Female; D008297:Male; D010929:Placentation; D011247:Pregnancy; D013552:Swine / Q000196:embryology*; D014599:Uterus / Q000502:physiology*