IntroductionThe ovarian follicular dynamics, vaginal electrical resistance (VER), progesterone (P4) and oestrogen (E2) profiles were investigated during the oestrous cycle in four indigenous ewes.Material and MethodsDaily VER values were recorded with a heat detector. The follicles were observed and measured by trans-rectal ultrasonography. Blood was collected daily for hormonal profiles.ResultsA significant variation in VER values (P < 0.05) in oestrus by ewes and position in the sequence of cycles was observed. Trans-rectal ultrasonography of ovaries revealed the presence of 2–4 waves of follicular growth. Study of hormonal profiles by ELISA revealed a positive correlation between E2 concentration and development of follicles and a negative correlation between P4 concentration and their development. The concentrations of oestradiol increased in oestrus and then decreased to a basal level. Follicular growth was accompanied by a rise in the concentration of serum oestradiol. Inversely, when follicles received the stimulation for ovulation, concentration of progesterone started to fall, but after ovulation, it climbed back to its peak and remained at this state until next ovulatory follicle reached its maximum diameter.ConclusionThis study could help to set up a manipulative reproductive technique for improving genetic values in indigenous sheep.

The effects of the number of frozen-thawed ram sperm per single and double intra-cervical artificial insemination (AI) on fertility in ewes were studied. A total of 89 non-pregnant ewes were synchronized for oestrus with two doses of 100 µg PGF 2α (Cloprostenol) 9 days apart. The ewes were randomly assigned to one of four groups; D200 (n = 23; double AI with 200 × 10 6 sperm), S200 (n = 24; single AI with 200 × 10 6 sperm), D100 (n = 24; double AI with 100 × 10 6 sperm) and S100 (n = 18; single AI with 100 × 10 6 sperm). Ewes were inseminated within 12 to 18 h for single AI and, within 10 to 12 h and 16 to 18 h for double AI after the onset of oestrus. The onset of oestrus ranged from 28 to 76 h (54.33 ± 1.28 h). The high percentage (29.2%) of ewes showed oestrus between 51 to 60 h. The non-return rates were highest in group D200 (56.5%) and differed significantly (p < 0.05) from group S100 (11.1%). No ewes were pregnant in group S100, and the pregnancy rates among the remaining groups did not differ. The mean gestation period was 152.8 ± 0.5 days and no difference was observed among the groups. The lambing and multiple birth rates were 100% in group D200. The single and twin lambing was highest in group D100 (33.3%) and group D200 (83.3%), respectively. Only one triplet lambing and the highest lambing size (2.2 ± 0.2) was recorded in group D200. In conclusion, double AI with 200 × 10 6 sperm showed comparatively most practical for achieving high pregnancy rates and lambing performances in Bangladeshi ewes under field conditions.