title: Long interval prostaglandin as an alternative to progesterone-eCG based protocols for timed AI in sheep.
abstract: To compare the reproductive performance after TAI in ewes synchronized with mid (12 or 13) or long (14-16 d) interval prostaglandin (PG) or progesterone plus eCG (P4-eCG) based protocols, 440 multiparous Corriedale ewes were synchronized with two PG injections administered 12-16 d apart (PG12, PG13, PG14, PG15 and PG16 respectively), or P4-eCG (MAP sponges 14 d and eCG). Cervical TAI (Day 0) was performed with fresh semen. It was evaluated the ovulated ewes (OE, %) and the ovulation rate (OR) on Day 8 by trans-rectal ultrasonography, the rate of non-return to service between Days 13 and 21 by painted rams, and the pregnancy rate, prolificacy and fecundity on Day 60 by trans-abdominal ultrasonography. No significant differences were found in OE among groups (P>0.05), but P4-eCG achieved higher OR (P<0.05) compared to PG protocols, without differences among them (P>0.05). Similar NRR-21, pregnancy and fecundity were observed among PG15 (64.3, 62.9 and 84.3), PG16 (59.7, 59.7 and 77.8) and P4-eCG (70.3, 66.2 and 95.9), but higher compared to PG12 (42.5, 39.7 and 52.1) and PG13 group (44.0, 40.0 and 48.0, respectively; P<0.05). PG14 achieved intermediate results compared to other groups. No differences were found in prolificacy among groups (P>0.05), except PG13 that was lower compared to P4-eCG (P<0.05). In conclusion, long interval between PG injections (15 or 16 d) determined better reproductive outcome that mid interval (12 or 13 d), equating the P4-eCG based protocol after cervical TAI with fresh semen during the breeding season in sheep.
authors.affiliation: Secretariado Uruguayo de la Lana (S.U.L.), Área de Transferencia de Tecnología, Servando Gómez 2408, Montevideo, Uruguay.
authors.forename: S
authors.initials: S
authors.lastname: Fierro
authors.affiliation: Laboratorio de Reproducción Animal "Dr. Alfredo Ferraris", Departamento de Ovinos, Lanas y Caprinos, Facultad de Veterinaria, Universidad de la República, Ruta 3 km 363, 60000, Paysandú, Uruguay. Electronic address: joliveramuz@gmail.com.
authors.forename: J
authors.initials: J
authors.lastname: Olivera-Muzante
mesh_terms: D000282:Administration, Intravaginal; D000818:Animals; D006063:Chorionic Gonadotropin; D015237:Dinoprost / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000494:pharmacology; D004334:Drug Administration Schedule; D005260:Female; D007315:Insemination, Artificial / Q000662:veterinary*; D017258:Medroxyprogesterone Acetate / Q000008:administration & dosage / Q000494:pharmacology; D011247:Pregnancy; D011374:Progesterone / Q000494:pharmacology; D011461:Prostaglandins F, Synthetic / Q000008:administration & dosage / Q000494:pharmacology*; D012756:Sheep / Q000502:physiology*
chemical_list: D006063:Chorionic Gonadotropin; D011461:Prostaglandins F, Synthetic; D011374:Progesterone; D015237:Dinoprost; D017258:Medroxyprogesterone Acetate; C050851:delprostenate
keywords: Ewe; Fertility; Progestagens; Prostaglandin; Timed artificial insemination