Effect of repeated laparoscopic surgery on the bovine estrous cycle.

The effects of repeated laparoscopic surgery on the length of the bovine estrous cycle, estrus, ovulation and corpus luteum function were determined after one estrous cycle of normal duration (18 to 24 days). Five, Angus x Hereford cows were subjected to laparoscopy on days 5, 13, 18 and 20 (estrus = day 0) of the subsequent cycle. Blood was collected daily during the cycle in which laparoscopy was performed (surgical cycle) and during the next cycle (postsurgical cycle). Lengths of the surgical and postsurgical cycles (22.3 +/- .5 days and 21.5 +/- .6 days, respectively) did not differ (P>.05) from that of the presurgical cycle (21.8 +/- .2 days). Average concentrations (ng/ml) of LH and progesterone in serum were similar during the surgical and postsurgical cycles (1.2 +/- .1, 2.2 +/- .2 vs 1.3 +/- .2 and 2.3 +/- .1). Progesterone concentrations remained above 1 ng/ml for 17 and 16 days during the surgical and postsurgical cycles, respectively. A pre-ovulatory rise in LH, along with estrus and ovulation was confirmed in all animals. Follicular development, characterized by follicular volume, increased progressively from days 5 to 20, with the largest increase occurring between days 13 and 18. These results indicate that laparoscopy, used at the times and frequency specified, does not alter reproductive function of cyclic cows and can provide information on ovarian activity.