Ovarian follicular dynamics in peripubertal Malabari goats

Abstract

The aim of this study was to characterise the follicular dynamics in first two oestrous cycles of peripubertal Malabari goats. Transrectal ultrasonography was carried out on alternate days of oestrous cycles after first observed oestrus. Follicular studies revealed presence of two to five wave cycles with predominant three and four wave patterns. The interwave interval for ovulatory wave was longer than preceding waves in three and five wave cycles. The diameter of largest follicles in wave 1 was larger than follicles of subsequent waves of three, four and five wave cycles. The largest follicles in each wave could be observed from day 3 to day 13 of oestrous cycle. Majority of ovulations occurred on day 20 of oestrous cycles and short cycles were more in first oestrous cycle. The overall mean per cent of single and double ovulations were 56.3 and 43.8 and mean ovulatory follicle size was 6.59 ± 0.11 mm in peripubertal goats. The mean length of first and second oestrous cycle was observed as 17.72± 0.79 and 20.19± 0.43 days, respectively and mean duration of first and second oestrus was 36.88 ± 2.44 and 40.13 ± 1.84 h, respectively. The study revealed that predominant wave pattern was three and four waves in peripubertal Malabari breeds. The first oestrous cycle length was shorter and characterised by higher percentage of single ovulations with smaller periovulatory follicle size. Larger ovulatory follicles and double ovulations were observed in second oestrous cycle.