title: Lactational estrus induction in the Mexican hairless sow.
abstract: The purpose of this study was to determine the effects on the reproductive performance of the Mexican hairless pig (MHP) while inducing fertile lactational estrus. Lactational estrus was induced on day 8, postpartum, in 20 primiparous sows during two consecutive reproductive cycles. Boar presence and temporary litter withdrawal were used as stimuli. Group I did not receive stimuli (control, C); group II had a 15 min boar stimulus (B); group III had litter withdrawal for 4 h (LW), and group IV received both stimuli (B + LW). Fertile estrus was detected by sow behavior, exfoliative vaginal cytology, and 17 beta-estradiol and progesterone samples. Individual stimuli did not induce fertile lactational estrus; nevertheless, when used together, both stimuli induced 100% of females into estrus, and 80% of them got pregnant while lactating. The partial withdrawal of the litter had a significant and positive effect on the number of live born piglets. Sows pregnant during lactation had shorter reproductive cycles, by not having non-productive days and litter size was greater. Pregnancy induction during lactation allowed the Mexican hairless sow to reduce the period between parturition's without diminishing the lactation length and litter performance.
authors.affiliation: Animal and Agriculture Department, Metropolitan Autonomous University-Xochimilco (UAM-X), Calzada del Hueso 1100, Colonia Villa Quietud, Mexico city, DF 04960, Mexico.
authors.forename: Daniel
authors.initials: D
authors.lastname: Mota
authors.forename: María
authors.initials: M
authors.lastname: Alonso-Spilsbury
authors.forename: Lilian
authors.initials: L
authors.lastname: Mayagoitia
authors.forename: María Elena
authors.initials: ME
authors.lastname: Trujillo
authors.forename: Javier
authors.initials: J
authors.lastname: Valencia
authors.forename: Ramiro
authors.initials: R
authors.lastname: Ramírez-Necoechea
mesh_terms: D000818:Animals; D000833:Animals, Suckling / Q000502:physiology*; D004958:Estradiol / Q000097:blood; D004971:Estrus / Q000502:physiology*; D005260:Female; D005298:Fertility; D007774:Lactation / Q000502:physiology*; D008098:Litter Size; D008297:Male; D011247:Pregnancy; D011374:Progesterone / Q000097:blood; D011897:Random Allocation; D013552:Swine / Q000502:physiology*; D014886:Weaning
chemical_list: D011374:Progesterone; D004958:Estradiol