Patterns of growth and regression of ovarian follicles during the oestrous cycle and after hemiovariectomy in mares

作者：Jean Sirois, B.A. Ball, J. E. Fortune · 发表于：Equine Veterinary Journal · 年份：1989 · DOI：10.1111/j.2042-3306.1989.tb04672.x · 被引用次数：67 · 研究领域：Reproductive Physiology in Livestock、Reproductive Biology and Fertility、Veterinary Equine Medical Research

Summary To increase our understanding of the regulation of ovarian follicular development during the oestrous cycle, 13 mares were used in two experiments. In Experiment 1, the pattern of growth and regression of individual follicles, 15 mm or more in size, was monitored daily during 17 oestrous cycles by real‐time ultrasonography. Each examination was recorded on videotape to ensure accurate monitoring of individual follicles. Results indicated that the development of such follicles occurs in waves, with the most common pattern being one follicular wave per oestrous cycle (12 of 17 cycles). An alternative pattern of two follicular waves per cycle was observed in mares with (n=3) and without (n=2) dioestrous ovulations. The ovulatory follicle appeared earlier in the cycle in mares with one wave than in mares with two waves (Day 6.3 ± 0.9 vs Day 11.0 ± 1.2, respectively; p<0.01). Also, the ovulatory follicle was the largest follicle for a longer period of time in mares with one wave than in mares with two waves per cycle (9.5 ± 0.6 vs 5.8 ± 0.3 days, respectively; p<0.01). Mares with one follicular wave had shorter cycles than those with two waves per cycle (18.2 ± 0.6 vs 21.6 ± 0.5 days, p<0.001). In both cases, the interval between the appearance of the ovulatory follicle and its ovulation was, on average, 10 to 12 days. Overall, a negative correlation was found between the relative size of the ovulatory follicle at the beginning of the follicular phase and the length of the...