title: Comparison between two progesterone sources and two oestradiol formulations in a Heatsynch protocol for postpartum cycling dairy cows in pasture.
abstract: To compare an injectable progesterone (MAD-4) with an intravaginal device (IPD), and natural O17 with synthetic oestradiol (OB) in a synchronisation protocol, 51 cows were divided into four groups. Each group was treated with one of the two sources of progesterone and one of the two oestradiol formulations. Oestrus behaviour, follicle diameter, and pregnancy rates were evaluated. Oestrus behaviour (p = 0.902), numbers of cows in oestrus (p = 0.917), follicle diameter (p = 0.416), and pregnancy rates (p = 0.873) were similar among the four groups. More cows in the group treated with the IPD and OB scored > 200 oestrus behaviour points compared to the other groups (p = 0.038). A longer interval between the end of treatment and oestrus was observed among cows treated with MAD-4 than cows given the IPD (p = 0.030), but no differences were found between animals receiving the two oestradiol formulations (OB and O17). While the use of MAD-4 requires further testing, similar responses to natural oestradiol observed in the present study could allow the use of this formulation in reproductive protocols because it is not associated with the potential human health risks of OB.
authors.affiliation: Department of Herd Health and Reproduction, Faculty of Veterinary Medicine, University of Utrecht, Utrecht 80125, The Netherlands.
authors.forename: Maarten F A
authors.initials: MF
authors.lastname: Andringa
authors.forename: Frank J C M
authors.initials: FJ
authors.lastname: Van Eerdenburg
authors.forename: Elisa
authors.initials: E
authors.lastname: Fernández
authors.forename: Sofía
authors.initials: S
authors.lastname: García
authors.forename: Daniel
authors.initials: D
authors.lastname: Cavestany
mesh_terms: D000282:Administration, Intravaginal; D000818:Animals; D002417:Cattle; D004958:Estradiol / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000494:pharmacology*; D004971:Estrus / Q000187:drug effects; D004973:Estrus Synchronization / Q000379:methods*; D005260:Female; D007279:Injections, Subcutaneous / Q000662:veterinary; D006080:Ovarian Follicle / Q000187:drug effects; D049590:Postpartum Period / Q000187:drug effects; D011247:Pregnancy; D018873:Pregnancy Rate; D011374:Progesterone / Q000008:administration & dosage / Q000494:pharmacology*; D012098:Reproduction / Q000187:drug effects
chemical_list: C074283:estradiol 3-benzoate; D011374:Progesterone; D004958:Estradiol
keywords: dairy cows; oestrus behaviour; synchronisation