title: Appetitive and Consummatory Sexual Behaviors of Rams Treated with Exogenous Testosterone and Exposed to Anestrus Dorper Ewes: Efficacy of the Male Effect.
abstract: We determine whether Dorper rams treated with testosterone in the sexual resting season trigger both appetitive and consummatory sexual behaviors and sexual and reproductive outcomes in anestrous ewes at 26° North during March-April. Dorper rams (n = 12, 2.5 years) were randomly divided prior to mating in two groups: GT (treated group; n = 6), treated with testosterone propionate (25 mg i.m. every 3 days × 3 weeks) and GC (control group; n = 6), treated with saline. Thereafter, adult anovulatory Dorper ewes (n = 61) were exposed to the GT-rams while the other group (n = 60) was exposed to the GC-rams. Ram's appetitive sexual behavior was similar (50 %) in both groups, yet the GT-rams exerted 100 % of the consummatory sexual behavior. Sexual and reproductive outcomes of the anestrus females exposed to both male groups considered two phases: 0-15 and 16-25 days from exposure to males. Involved variables were: ewes in estrus, ewes ovulating, duration of estrus, pregnant ewes, and lambed ewes. All the average variables favored those ewes exposed to GT-males: ewes in estrus: 85 versus 40 %; ewes ovulating: 80 versus 53 %; duration of estrus: 37 versus 25 h; pregnant ewes: 60 versus 31 %, and lambed ewes: 57 versus 31 %. Results confirm that adult Dorper rams treated with exogenous testosterone had improved consummatory sexual behavior and induced increased ovulation and pregnancy rates when exposed to anestrus ewes. This feasible and inexpensive testosterone-based protocol through the male effect also enhanced both sexual and reproductive outcomes in previously anestrous Dorper ewes during the natural out-of-season. Results are important to speed up reproductive performance of sheep during the natural anestrous season at this latitude, while also they embrace interesting outcomes from a comparative sexual behavior stand point.
authors.affiliation: Universidad Autónoma Agraria Antonio Narro, Periférico Raúl López Sánchez y Carretera a Santa Fe, 27054, Torreón, Coahuila, Mexico.
authors.forename: Luz M
authors.initials: LM
authors.lastname: Tejada
authors.affiliation: Unidad Regional Universitaria de Zonas Áridas, Universidad Autónoma Chapingo, 35230, Bermejillo, Durango, Mexico.
authors.forename: Cesar A
authors.initials: CA
authors.lastname: Meza-Herrera
authors.affiliation: Instituto Tecnológico de Torreón, San Pedro Km 7.5, Torreón, Coahuila, Mexico.
authors.forename: Raymundo
authors.initials: R
authors.lastname: Rivas-Muñoz
authors.affiliation: Universidad Autónoma Agraria Antonio Narro, Periférico Raúl López Sánchez y Carretera a Santa Fe, 27054, Torreón, Coahuila, Mexico.
authors.forename: Rafael
authors.initials: R
authors.lastname: Rodríguez-Martínez
authors.affiliation: Instituto Tecnológico de Torreón, San Pedro Km 7.5, Torreón, Coahuila, Mexico.
authors.forename: Evaristo
authors.initials: E
authors.lastname: Carrillo
authors.affiliation: Universidad Autónoma Agraria Antonio Narro, Calzada Antonio Narro 1923, Colonia Buenavista, 25315, Saltillo, Coahuila, Mexico.
authors.forename: Miguel
authors.initials: M
authors.lastname: Mellado
authors.affiliation: Universidad Autónoma Agraria Antonio Narro, Periférico Raúl López Sánchez y Carretera a Santa Fe, 27054, Torreón, Coahuila, Mexico. velizderas@gmail.com.
authors.forename: Francisco G
authors.initials: FG
authors.lastname: Véliz-Deras
mesh_terms: D000780:Anestrus / Q000187:drug effects*; D000818:Animals; D005260:Female; D008297:Male; D011897:Random Allocation; D012726:Sexual Behavior, Animal / Q000187:drug effects*; D012756:Sheep / Q000502:physiology*; D013739:Testosterone / Q000008:administration & dosage / Q000494:pharmacology
chemical_list: D013739:Testosterone
keywords: Anestrus season; Dorper ewes; Male effect; Reproductive outcomes; Testosterone