Poor estrus expression and the difficulty encountered in predicting the time of ovulation
compromise the reproductive efficiency of Murrah buffalo cows. Synchronization of
ovulation and timed artificial insemination are able to precisely control the time of
ovulation and thus avoid the need for estrus detection. Recently, the Estradoublesynch
protocol (administration of a PGF2a injection 2 days before Heatsynch protocol; GnRH 0,
PGF2a 7, estradiol benzoate [EB] 8) was developed that precisely synchronized ovulation
twice, i.e., after GnRH and EB injections and resulted in satisfactory pregnancy rates in
Murrah buffaloes. The present study was conducted on 104 cycling and 31 anestrus buffaloes
to compare (1) the endocrine changes, timing of ovulations, ovarian follicular
growth, and efficacy of Estradoublesynch and Heatsynch protocols in cycling and (2) the
efficacy of Estradoublesynch and Heatsynch protocols for the improvement of fertility in
cycling and anestrus Murrah buffalo cows. Ovulation was confirmed after all GnRH and EB
treatments by ultrasonographic examination at 2-hour intervals. Plasma progesterone and
total estrogen concentrations were determined in blood samples collected at daily intervals,
beginning 2 days before the onset of protocols until the day of second ovulation
detection. Ovulatory follicle size was measured by ultrasonography at six time points (first
PGF2a administration of Estradoublesynch protocol every 2 days before the onset of
Heatsynch protocol, GnRH administration of both protocols, 2 hours before ovulation
detection after GnRH administration of both protocols, second PGF2a injection of Estradoublesynch
protocol, PGF2a injection of Heatsynch protocol, EB injection of both protocols
and, 2 hours before ovulation detection after EB administration of both protocols).
Plasma LH, total estrogen, and progesterone concentrations were determined in blood
samples collected at 30-minute intervals for 8 hours, beginning GnRH and EB injections
