title: Efficacy of the Ovsynch protocol for synchronization of ovulation and fixed-time artificial insemination in Murrah buffaloes (Bubalus bubalis).
abstract: Two experiments were conducted to assess the timing and synchrony of ovulation, plasma LH concentrations, and pregnancy rate in Murrah buffaloes (Bubalus bubalis) treated with the Ovsynch (GnRH-PGF(2 alpha)-GnRH) protocol. In Experiment 1, 10 non-lactating cycling buffaloes received 10 microg of a GnRH analogue i.m. (buserelin acetate) without regard to the stage of the estrous cycle (day of treatment, day 0), followed by 25mg of PGF(2 alpha) i.m. (dinoprost thromethamine) 7 days later. A second-treatment of the same GnRH analogue (10 microg, i.m.) was given 48 h after PGF(2 alpha). Ovulation was confirmed by transrectal palpation (at 2-h intervals) from the second-GnRH treatment to detection of ovulation or up to 96 h after the second-GnRH treatment. Plasma LH concentrations were determined in blood samples collected at 15-min intervals for 6h, starting at the second-GnRH treatment, and thereafter at 2-h intervals until 2h after detection of ovulation. Ovulation occurred in 9/10 buffalo (90%) 23.3+/-1.3h (mean+/-S.E.M.; range 20--32 h) after the second-GnRH treatment. Peak LH concentrations 13.5+/-3.5 ng/mL (range 3.9--40.0 ng/mL) occurred 2.1+/-0.1h (range 1.2-3.0 h) after the second-GnRH treatment. In Experiment 2, 15 lactating, cycling buffaloes were subjected to the Ovsynch protocol, with fixed-time AI 12 and 24h after the second-GnRH treatment and 75 lactating buffaloes were inseminated, approximately 12h after detection of spontaneous estrus. Pregnancy rates were 33.3% for TAI and were 30.7% for buffaloes inseminated following spontaneous estrus (P=0.84). In conclusion, the Ovsynch protocol effectively synchronized ovulation in Murrah buffaloes and resulted in conception rates (to two fixed-time inseminations) that were comparable to those achieved with a single AI after detection of spontaneous estrus.
authors.affiliation: Division of Dairy Cattle Physiology, National Dairy Research Institute, Karnal 132001 Haryana, India. vijaypaul_74@rediffmail.com
authors.forename: Vijay
authors.initials: V
authors.lastname: Paul
authors.forename: B S
authors.initials: BS
authors.lastname: Prakash
mesh_terms: D000818:Animals; D002020:Buffaloes / Q000502:physiology*; D002064:Buserelin / Q000008:administration & dosage*; D015237:Dinoprost / Q000008:administration & dosage*; D005260:Female; D007987:Gonadotropin-Releasing Hormone / Q000031:analogs & derivatives; D007315:Insemination, Artificial / Q000379:methods / Q000662:veterinary*; D007774:Lactation; D007986:Luteinizing Hormone / Q000097:blood; D010062:Ovulation Induction / Q000379:methods / Q000662:veterinary*; D011247:Pregnancy; D013997:Time Factors
chemical_list: D007987:Gonadotropin-Releasing Hormone; D007986:Luteinizing Hormone; D015237:Dinoprost; D002064:Buserelin