Experiments were conducted to investigate (1) ovarian follicular growth, timing of
ovulation and associated endocrine changes (progesterone, estrogen, and LH) in cycling,
and (2) efficacy in terms of pregnancy rate in cycling and anestrus Murrah buffaloes
subjected to the Estradoublesynch protocol (prostaglandin F2a [PGF2a] 0, GnRH 2, PGF2a 9,
estradiol benzoate, EB 10). Twelve cycling buffaloes were subjected to the Estradoublesynch
protocol and observed for ovulation, follicle size, and endocrine changes after EB
treatment. Ovulation occurred in 12 of 12 buffaloes (100%) at 48.5 1.6 hours (range,
38.0–56.0) after EB treatment. Plasma LH, total estrogen, and progesterone concentrations
were determined in intensive blood samples collected after EB treatment. Peak LH concentration
of 34.2 7.7 ng/mL (range, 17.8–178.5) occurred at 18.3 0.8 hours (range,
14.0–22.0) after EB treatment. Peak total estrogen of 50.8 6.9 pg/mL (range, 32.3–82.7)
occurred 5.7 1.0 hours (range, 2.0–14.0) after EB treatment. Follicle size was gradually
increased from second PGF2a injection (9.7 0.3 mm; range, 8.0–12.0) until ovulation was
detected (12.9 0.4 mm; range, 11.0–15.0). Fourteen cycling and 11 anestrus buffaloes
were subjected to the Estradoublesynch protocol, with timed artificial insemination (TAI)
48 and 60 hours after EB treatment, and 58 cycling buffaloes were inseminated after
spontaneous estrus (control group). Pregnancy rates were 62% for TAI of cycling buffaloes,
64% for anestrus buffaloes, and 34.5% for control group. Our observations demonstrated
that the Estradoublesynch protocol followed by TAI satisfactory enhanced pregnancy rates
in both cycling and anestrus buffaloes.
