title: Pathways of the dominant follicle after exposure to sub-luteal circulating progesterone concentrations are different in lactating dairy cows versus non-lactating heifers.
abstract: With the increased use of different synchronization programs in cattle, attention is given to the progesterone concentration during development of the ovulatory follicle. It has been shown that low peripheral progesterone concentrations during follicular development may lead to decreased fertility. To investigate the effect of low progesterone concentrations on the fate of the dominant follicle, a study was conducted where cycles of dairy cows and heifers were manipulated to induce the development of the first dominant follicle without progesterone (PLACEBO) or under sub-luteal progesterone concentrations from a progesterone releasing intravaginal device (PRID Delta(®)). After insertion of the devices, daily follow up was performed by transrectal ultrasonography to identify and measure follicular development and blood samples were taken to determine the circulating progesterone concentration. Follow up was continued until the ovulation of a follicle occurred. After ovulation, the fate of the first dominant follicle was identified as arrested, atretic or ovulatory. Arrest was defined as persistence of the dominant follicle followed by ovulation whereas atresia was defined as regression of the dominant follicle and subsequent growth and ovulation of a new follicle. During PLACEBO treatment, heifers ovulated earlier and smaller follicles in comparison to cows. During PRID Delta(®) treatment, heifers had greater progesterone concentrations compared to cows and arrest of the dominant follicle occurred more in cows in comparison to heifers. In cycles where the dominant follicle was arrested, the ovulatory follicle was larger in comparison to cycles where the dominant follicle was atretic.
authors: Department of Reproduction and Biomedicine, Faculty of Veterinary Medicine, "Ss. Cyril and Methodius" University, Lazar Pop Trajkov 5/7, 1000 Skopje, The Former Yugoslav Republic of Macedonia; Department of Reproduction, Obstetrics and Herd Health, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, 9820 Merelbeke, Belgium.
authors: B
authors: B
authors: Atanasov
authors: Department of Reproduction, Obstetrics and Herd Health, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, 9820 Merelbeke, Belgium.
authors: J
authors: J
authors: De Koster
authors: Biocentrum Agri-Vet Faculty of Veterinary Medicine, Ghent University, Proefhoevestraat 18, 9090 Melle, Belgium.
authors: L
authors: L
authors: Bommelé
authors: Department of Reproduction and Biomedicine, Faculty of Veterinary Medicine, "Ss. Cyril and Methodius" University, Lazar Pop Trajkov 5/7, 1000 Skopje, The Former Yugoslav Republic of Macedonia.
authors: T
authors: T
authors: Dovenski
authors: Department of Reproduction, Obstetrics and Herd Health, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, 9820 Merelbeke, Belgium. Electronic address: Geert.Opsomer@Ugent.be.
authors: G
authors: G
authors: Opsomer
mesh_terms: D000375:Aging; D000818:Animals; D002417:Cattle / Q000097:blood / Q000502:physiology*; D015237:Dinoprost / Q000008:administration & dosage / Q000031:analogs & derivatives / Q000494:pharmacology; D030762:Estrous Cycle; D004973:Estrus Synchronization / Q000187:drug effects; D005260:Female; D007774:Lactation / Q000097:blood / Q000502:physiology*; D006080:Ovarian Follicle / Q000502:physiology*; D010298:Parity; D011374:Progesterone / Q000008:administration & dosage / Q000097:blood / Q000494:pharmacology*
chemical_list: D011374:Progesterone; D015237:Dinoprost; C010714:dinoprost tromethamine
keywords: Arrest; Atresia; Dairy cow; Dairy heifer; Dominant follicle; Progesterone releasing intravaginal device