Temporal relationships between minor, preovulatory, or periovulatory FSH surges and the emergence and development of 2-mm follicles of wave 1 in Bos taurus heifers

The number and day of emergence (first detection) of 2-mm follicles and the number and day when the 2-mm follicles reached 3-, 4-, 5-, and 6-mm during wave 1 were determined every 0.5 d (n = 9 heifers). Emergence of the follicles at each of the indicated diameters was normalized to the beginning and ending nadir and the peak of each of a minor FSH surge, the preovulatory surge and the periovulatory surge. Relative to the day of ovulation (Day 0), the minor FSH surge, preovulatory surge, and periovulatory surge encompassed (nadir to nadir) Days −7.0 to −2.5 (peak, Day −4.0), Days −2.5 to −0.5 (peak, Day −1.0), and Days −0.5 to 4 (peak, Day 0), respectively.

Source: Domestic Animal Endocrinology - May 26, 2016 Category: Endocrinology Authors: J.M. Baldrighi, M.A.R. Siddiqui, O.J. Ginther Source Type: research