title: Effect of active immunization of pre-partum and post-partum cows against prostaglandin F-2 alpha on lifespan and progesterone secretion of short-lived corpora lutea.
abstract: Mature beef cows were actively immunized pre partum (N = 5) or post partum (N = 10) against a PGF-2 alpha-ovalbumin conjugate or against ovalbumin alone (control; N = 5). All cows in the control group exhibited first oestrous cycles which were of short duration (less than or equal to 12 days). Mean specific serum binding to [3H]PGF-2 alpha in the control group was consistently less than 1%. In the pre-partum PGF-2 alpha-immunized cows, lifespan and progesterone secretion of the first corpus luteum formed post partum was maintained for greater than 39 days. Specific serum binding to [3H]PGF-2 alpha in pre-partum and post-partum PGF-2 alpha-immunized cows was elevated. Lifespan of the first corpus luteum formed in post-partum PGF-2 alpha-immunized cows was short (less than 10 days; N = 1), normal (mean = 22 days; N = 4) or maintained (greater than 31 days; N = 5). Luteal lifespan was dependent upon serum PGF-2 alpha antibody titres, with cows exhibiting higher titres frequently having prolonged luteal lifespans after first ovulation. We conclude that active immunization of beef cows against PGF-2 alpha extends the lifespan and progesterone secretion of corpora lutea anticipated to be short-lived. These results support the concept that the shorter lifespan of some corpora lutea in post-partum cows is due to a premature release of PGF-2 alpha from the uterus.
authors.affiliation: Department of Animal Science, University of Missouri, Columbia 65211.
authors.forename: J P
authors.initials: JP
authors.lastname: Copelin
authors.forename: M F
authors.initials: MF
authors.lastname: Smith
authors.forename: D H
authors.initials: DH
authors.lastname: Keisler
authors.forename: H A
authors.initials: HA
authors.lastname: Garverick
mesh_terms: D000818:Animals; D002417:Cattle; D003338:Corpus Luteum / Q000378:metabolism / Q000502:physiology*; D015237:Dinoprost / Q000276:immunology / Q000502:physiology*; D005260:Female; D007114:Immunization; D003341:Luteolysis / Q000502:physiology*; D049590:Postpartum Period / Q000502:physiology*; D011247:Pregnancy; D011374:Progesterone / Q000378:metabolism*
chemical_list: D011374:Progesterone; D015237:Dinoprost