title: Reproductive and sexual behaviour development of dam or artificially reared male lambs.
abstract: The objective of this study was to determine if artificially reared male lambs differ from those reared by their mothers in their reproductive development and sexual behaviour during the first breeding season and in their serum testosterone to a GnRH challenge at the end of the first breeding season. Lambs were assigned to two experimental groups: 1) artificially reared lambs, separated from their dams 24-36h after birth (Week 0) and fed sheep milk until 10weeks of age (group AR, n=14); and 2) lambs reared by their dams until 10weeks of age (group DR, n=13). Reproductive parameters and sexual behaviour were recorded from Weeks 9 to 39. The GnRH challenge was performed on Week 40. Body weight, scrotal circumference, gonado-somatic index, testosterone concentration and sperm parameters were unaffected by group, but increased with age (P<0.0001). Lambs reared by their mothers had greater values of gonado-somatic index on Weeks 9, 16 and 19 (P<0.05), and tended to reach puberty earlier than AR (22.9±0.7 vs. 25.1±1.1weeks, respectively, P=0.087). Lambs reared by their mothers presented more lateral approaches and mount attempts than AR (P<0.05), and DR lambs presented more mounts on Weeks 32 and 39 than AR (P<0.05). Blood testosterone concentrations 3.5 and 4h after the GnRH challenge were higher in AR than in DR lambs (P<0.05). In conclusion mother rearing promoted sexual behaviour and reproductive performance of male lambs.
authors.affiliation: Departamento de Biología Molecular y Celular, Facultad de Veterinaria, Universidad de la República, Montevideo, Uruguay. Electronic address: jpablodamian@gmail.com.
authors.forename: Juan Pablo
authors.initials: JP
authors.lastname: Damián
authors.affiliation: Departamento de Fisiología, Facultad de Veterinaria, Universidad de la República, Uruguay.
authors.forename: Florencia
authors.initials: F
authors.lastname: Beracochea
authors.affiliation: Laboratório de Etologia Aplicada e Bem-Estar Animal, Departamento de Zootecnia e Desenvolvimento Rural, Universidade Federal de Santa Catarina, Florianópolis, Brazil.
authors.forename: Maria José
authors.initials: MJ
authors.lastname: Hötzel
authors.affiliation: Unidad de Ovinos, INIA "La Estanzuela", Colonia, Uruguay.
authors.forename: Georgget
authors.initials: G
authors.lastname: Banchero
authors.affiliation: Departamento de Fisiología, Facultad de Veterinaria, Universidad de la República, Uruguay.
authors.forename: Rodolfo
authors.initials: R
authors.lastname: Ungerfeld
mesh_terms: D000367:Age Factors; D000704:Analysis of Variance; D000818:Animals; D001835:Body Weight / Q000187:drug effects; D001947:Breeding; D005837:Genitalia, Male / Q000033:anatomy & histology; D007987:Gonadotropin-Releasing Hormone / Q000494:pharmacology; D008297:Male; D009034:Mother-Child Relations / Q000523:psychology*; D012098:Reproduction / Q000502:physiology*; D012726:Sexual Behavior, Animal / Q000187:drug effects / Q000502:physiology*; D046468:Sexual Development / Q000187:drug effects / Q000502:physiology*; D034561:Sheep, Domestic; D013094:Spermatozoa / Q000502:physiology; D013739:Testosterone / Q000097:blood
chemical_list: D007987:Gonadotropin-Releasing Hormone; D013739:Testosterone
keywords: GnRH; Mother–offspring bond; Sheep; Sperm; Testosterone