Ovarian and endocrine responses and efficacy associated with three ovulation synchronization strategies (Heatsynch, Doublesynch and Estradoublesynch) in Murrah buffaloes

Abstract Text:

Experiments were conducted on 71 cycling and 37 anestrus buffalos to investigate; a) the endocrine changes, timing of ovulation and efficacy of Estradoublesynch (PGF_2α 0, GnRH 2, PGF_2α 9, Estradiol Benzoate; EB 10), Heatsynch (GnRH 0, PGF_2α 7, EB 8) and Doublesynch (PGF_2α 0, GnRH 2, PGF_2α9, GnRH 11) protocols in cycling buffaloes, and b) to compare the efficacy of Estradoublesynch, Heatsynch and Doublesynch protocols for fertility improvement in cycling and anestrus buffaloes. Follicle size and ovulation rate were determined following all GnRH and EB treatments using transrectal ultrasonography at 2-h intervals. Plasma progesterone and total estrogen concentrations were determined in blood samples collected at daily intervals, beginning 2 days before onset of protocols until day of second ovulation detection. Plasma LH, total estrogen and progesterone concentrations were determined in blood samples collected at 30-min intervals post GnRH and EB injections until detection of ovulation. The first ovulatory rates were significantly (P<0.05) higher in Doublesynch (90%) and Estradoublesynch (83.3%) protocols than that in Heatsynch protocol (36.4%). The first LH Peak concentrations in Estradoublesynch (73.3±9.2 ng/ml) and Doublesynch (99.8±28.5 ng/ml) protocols were significantly (P<0.05) higher than that of Heatsynch (55.3±7.4 ng/ml) protocol. In both Estradoublesynch and Doublesynch protocols, the total estrogen concentration gradually increased from the day of GnRH administration coinciding with LH peak, and then gradually declined to the basal level until the time of ovulation detection. However, in Heatsynch protocol, the gradual increase in total estrogen concentration after GnRH was observed only in those buffaloes which responded to treatment with ovulation. In both Estradoublesynch and Heatsynch protocols, ovulatory follicles size increased from GnRH/EB injections until ovulation. The pregnancy rates after Estradoublesynch (62.2%) and Doublesynch (58.1%) protocols were significantly (P<0.05) higher than that achieved after Heatsynch protocol (32.5%). Our observations demonstrated that the Estradoublesynch and Doublesynch protocols can be potentially used to obtained satisfactory pregnancy rates after TAI in both cycling and anestrus buffaloes.

Keywords: Estradoublesynch, Heatsynch, Doublesynch