Effects of preovulatory follicle size on estradiol concentrations, corpus luteum diameter, progesterone concentrations and subsequent pregnancy rate in buffalo cows (Bubalus bubalis)

The present study was undertaken to investigate the effects of preovulatory follicle (POF) size on estradiol concentrations, luteal profile (CL diameter and progesterone concentration) and subsequent pregnancy rate in Murrah buffalo cows. The buffalo cows (n = 49) were synchronized for estrus by two doses of PGF2α given 11 days apart. The buffalo cows were inseminated during standing estrus and again after 24 h. Ovaries were scanned at estrus and 24 h intervals until ovulation, thereafter on days 5, 12 and 16 post-ovulation to examine the POF and CL diameter. Size of POF at estrus was divided into three categories; I: 10 to ≤12; II: >12.0 to ≤14.0; III: >14.0–16.0 mm. Blood samples were collected for estradiol (on day of estrus) and progesterone concentration (on days 5, 12 and 16). The estradiol concentrations were greater (P