Effect of calf isolation and restricted suckling on LH secretion in postpartum suckler cows

Extract

In suckler cows follicular development resumes early in the postpartum period, but failure of successive dominant follicles to ovulate results in a prolonged interval from calving to first ovulation (postpartum interval, PPI). Calf isolation and restricted suckling induce ovulation of either the current or subsequent dominant follicle (DF), probably due to changes in LH pulsatility, but this ovulation is generally silent and followed by an 8-10 day cycle due to lack of progesterone priming. The aim of this study was threefold: 1) to examine the acute effects of calf isolation and restricted suckling on LH pulse frequency and PPI, 2) to determine if progesterone priming would eliminate silent heats and short cycles, and 3) to determine if oestradiol treatment would cause atresia of the current dominant follicle and induce new wave emergence providing a “fresh” dominant follicle at progesterone withdrawal.