Effect of treatment with progesterone on pregnancy rate and plasma concentrations of progesterone in Holstein cows.
Progesterone-releasing intravaginal devices inserted into the vaginas of dairy cows between d 5 to 12 (n = 28) or d 10 to 17 (n = 27) after insemination increased pregnancy rate to 60 over 30% in untreated control cows (n = 30). Plasma progesterone concentrations were increased during both progesterone treatments. Subtraction of the estimated contribution of exogenous progesterone indicated that endogenous, luteal progesterone was reduced during d 10 to 17 but not during d 5 to 12. Supplemental progesterone increased pregnancy rate but suppressed endogenous production of progesterone when administered during d 10 to 17 after insemination.
Robinson
N A
NA
Department of Animal and Poultry Science, University of Guelph, Ontario, Canada.
Leslie
K E
KE
Walton
J S
JS
D000282:Administration, Intravaginal; D000818:Animals; D002417:Cattle / Q000502:physiology*; D003692:Delayed-Action Preparations; D005260:Female; D007315:Insemination, Artificial / Q000662:veterinary*; D011247:Pregnancy; D011270:Pregnancy, Animal / Q000187:drug effects*; D011374:Progesterone / Q000008:administration & dosage / Q000097:blood / Q000494:pharmacology*
D003692:Delayed-Action Preparations; D011374:Progesterone