title: Sexually active males prevent the display of seasonal anestrus in female goats.
abstract: A well-defined season of sexual rest controlled by photoperiod is observed in female sheep and goats during spring and summer, delineating their "anestrous season"; bucks also decrease sexual activity at about the same time. Nutrition and/or socio-sexual stimuli play only secondary roles. However, the presence of sexually active males can reduce the length of seasonal anestrus. Whether it can also completely suppress anestrus has not been investigated. Here we tested this in goats in 3 experiments, using bucks rendered sexually active out of season by exposure to long days. The continuous presence of these males prevented goats to display seasonal anestrus: 12/14 females cycled the year round, vs. 0/13 and 0/11 for females with un-treated bucks or without bucks (experiment 1). When active bucks were removed, females immediately entered anestrus (7/7 stopped ovulating vs. 1/7 if maintained with active bucks; experiment 2). Finally, 7/7 anestrous does with bucks in sexual rest since 1.5months commenced cycling rapidly during mid-anestrous, when these bucks became sexually active following a treatment with artificial long days, vs. 0/7 with un-treated bucks or no bucks (experiment 3). The presence/withdrawal of active bucks had a highly significant effect in the three experiments (P≤0.002). Therefore, the presence of a mating opportunity can completely override the photoperiodic inhibition of reproduction of females throughout the anestrous season. Results suggest that we must re-evaluate the relative contributions of photoperiod vs. other external cues in controlling seasonal reproduction, thus offering new non-pharmaceutical ways for controlling out-of-season reproduction in small ruminants.
authors.affiliation: Centro de Investigación en Reproducción Caprina, Universidad Autónoma Agraria Antonio Narro, Periférico Raúl López Sánchez y Carretera a Santa Fe, C.P. 27054 Torreón, Coahuila, Mexico. Electronic address: joaldesa@yahoo.com.
authors.forename: J A
authors.initials: JA
authors.lastname: Delgadillo
authors.affiliation: Centro de Investigación en Reproducción Caprina, Universidad Autónoma Agraria Antonio Narro, Periférico Raúl López Sánchez y Carretera a Santa Fe, C.P. 27054 Torreón, Coahuila, Mexico.
authors.forename: J A
authors.initials: JA
authors.lastname: Flores
authors.affiliation: Centro de Investigación en Reproducción Caprina, Universidad Autónoma Agraria Antonio Narro, Periférico Raúl López Sánchez y Carretera a Santa Fe, C.P. 27054 Torreón, Coahuila, Mexico.
authors.forename: H
authors.initials: H
authors.lastname: Hernández
authors.affiliation: INRA, CNRS, Univ Tours, Haras Nationaux, UMR 7247 Physiologie de la Reproduction et des Comportements, F-37380 Nouzilly, France.
authors.forename: P
authors.initials: P
authors.lastname: Poindron
authors.affiliation: INRA, CNRS, Univ Tours, Haras Nationaux, UMR 7247 Physiologie de la Reproduction et des Comportements, F-37380 Nouzilly, France.
authors.forename: M
authors.initials: M
authors.lastname: Keller
authors.affiliation: Centro de Investigación en Reproducción Caprina, Universidad Autónoma Agraria Antonio Narro, Periférico Raúl López Sánchez y Carretera a Santa Fe, C.P. 27054 Torreón, Coahuila, Mexico.
authors.forename: G
authors.initials: G
authors.lastname: Fitz-Rodríguez
authors.affiliation: Centro de Investigación en Reproducción Caprina, Universidad Autónoma Agraria Antonio Narro, Periférico Raúl López Sánchez y Carretera a Santa Fe, C.P. 27054 Torreón, Coahuila, Mexico.
authors.forename: G
authors.initials: G
authors.lastname: Duarte
authors.affiliation: Centro de Investigación en Reproducción Caprina, Universidad Autónoma Agraria Antonio Narro, Periférico Raúl López Sánchez y Carretera a Santa Fe, C.P. 27054 Torreón, Coahuila, Mexico.
authors.forename: J
authors.initials: J
authors.lastname: Vielma
authors.affiliation: Centro de Investigación en Reproducción Caprina, Universidad Autónoma Agraria Antonio Narro, Periférico Raúl López Sánchez y Carretera a Santa Fe, C.P. 27054 Torreón, Coahuila, Mexico.
authors.forename: I G
authors.initials: IG
authors.lastname: Fernández
authors.affiliation: INRA, CNRS, Univ Tours, Haras Nationaux, UMR 7247 Physiologie de la Reproduction et des Comportements, F-37380 Nouzilly, France.
authors.forename: P
authors.initials: P
authors.lastname: Chemineau
mesh_terms: D000780:Anestrus / Q000502:physiology*; D000822:Animal Husbandry; D000818:Animals; D003380:Courtship; D005260:Female; D006041:Goats / Q000502:physiology*; D008297:Male; D010060:Ovulation / Q000502:physiology; D017440:Photoperiod; D012098:Reproduction / Q000502:physiology; D012621:Seasons; D012726:Sexual Behavior, Animal / Q000502:physiology*; D012931:Social Environment
keywords: Anovulation; Caprine; Circannual rhythm; GnRH–LH; Olfaction; Ovulatory activity; Photoperiod; Sexual behavior