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.

The study was aimed to identify the effective cervical ripening treatment to increase the pregnancy rates following transcervical artificial insemination (TC-AI) in indigenous ewes of Bangladesh. Three treatments schedules were compared, G1 (n = 6, control), G2 *n = 6, prostaglandin E1 (PGE1) as Misoprostol-Cytomis®+ and G3 (n = 6, estrogen as Oestriol-Ovestin® + oxytocin as Linda-S® Vet). Ewes (n=18) were synchronized for estrus using two doses of 100 µg prostaglandin (PGF2α; Ovuprost®) 9 days apart. The cervical ripening treatments were administered just after the onset of estrus and left for 12 h before TC-AI. The cervical ripening was reflected with the depth of cervical penetration. The depth of cervical penetration in G1, G2 and G3 both before and after cervical ripening treatments were 0.33 ± 0.10 cm vs 0.43 ± 0.07 cm, 0.41 ± 0.09 cm vs 3.50 ± 0.26 cm and 0.43 ± 0.09 cm vs 1.54 ± 0.14 cm, respectively. The depth of cervical penetration increased significantly (p<0.01) in G2 and (p<0.05) in G3 compared with G1. Comparing the pregnancy rates, no significant difference was observed among the groups. However, the pregnancy rates were increased (66.67%) in G2 near to significant compared to G1 (33.33%). In conclusion, the depth of cervical penetration and pregnancy rates was deeper and higher with PGE1-Misoprostol treatment. This preliminary study enlightens the development of effective TC-AI techniques in indigenous ewes for its satisfactory pregnancy rates and, to accept by the Bangladeshi sheep farmers. Furthermore, this study provides some important results that suggest room for further research with a greater number of ewes.