title: The effect of a mixed-management system on the release of oxytocin, prolactin, and cortisol in ewes during suckling and machine milking.
abstract: Milk yield and plasma oxytocin (OT), prolactin (PRL), and cortisol (CORT) during suckling and machine milking were measured in multiparous ewes subjected to a mixed management system of 3 sucklings and two daily milkings. Peak hormones were significantly increased and were similar during suckling and milking for PRL (181 vs. 163.3 ng x mL(-1)) and CORT (12.5 vs. 11.5 ng x mL(-1)). During the period of exclusive suckling, OT was always significantly released (90.3 pg x mL(-1)); however, during the period of mixed management, OT concentrations only increased during suckling compared to milking (91.7 vs. 13.1 pg x mL(-1)). The mean volume of milk obtained during suckling (632 mL) was significantly higher than during milking (255 mL). Thus, during a mixed management system, oxytocin and prolactin releases are not under similar central regulation. A mixed system, without OT release during milking, does not contribute to accelerate the conditioning of ewes for machine milking.
authors.affiliation: Equipe Associée INRA/ENSAR de Recherches sur la Traite, Rennes, France. marnet@roazhon.inra.fr
authors.forename: P G
authors.initials: PG
authors.lastname: Marnet
authors.forename: J A
authors.initials: JA
authors.lastname: Negrão
mesh_terms: D000818:Animals; D000833:Animals, Suckling; D003612:Dairying / Q000379:methods*; D005260:Female; D006854:Hydrocortisone / Q000097:blood*; D007774:Lactation; D010121:Oxytocin / Q000097:blood*; D011388:Prolactin / Q000097:blood*; D012756:Sheep; D013997:Time Factors
chemical_list: D010121:Oxytocin; D011388:Prolactin; D006854:Hydrocortisone