Abstract
Multiple Ovulation and Embryo Transfer can speed up the genetic improvement of sheep. The objectives of the study were to observe the reproductive performances, develop an effective oestrus synchronization and MOET technique in indigenous ewes in Bangladesh. The reproductive performances were monitored by comparing the data between control and supplemented groups. All donor and recipient ewes were synchronized by injecting Cloprostenol (100 or 175 μg) nine days apart or by inserting intravaginal sponges impregnated with Fluorogesterone acetate (FGA; 30 mg or 45 mg) for 12 days. Donor ewes were superovulated either injecting Pregnant Mare Serum Gonadotrophin (PMSG) or Porcine Follicular stimulating Hormone (pFSH). Oestrus donor ewes were laparoscopically inseminated and/ or naturally mated. The embryos were recovered and transferred either by using surgical or laparoscopic method on Day 5 or 6 following insemination. Supplemented feeding significantly increased the reproductive parameters. The onset of oestrus occurred earlier (17.1±0.45 hr) in ewes induced with 45 mg FGA than 30 mg or Cloprostenol groups (P<0.05). The mean number of corpora lutea (CL; 11.7±1.01) and embryos recovered (9.0±0.85) were also significantly higher (P<0.05) in ewes given 45 mg FGA and pFSH than 30 mg FGA. The similar results (P<0.001) were obtained when data were pooled over. The number of embryos (5.2±0.46) and the recovery rate (62.9%) was significantly higher after 600 iu PMSG than with 450, 500, 750 or 900 iu (P<0.05). The mean number of CL (13.7±0.7 vs. 9.3±0.20) and total embryos recovered (11.1±0.52 vs. 6.8±0.37) were significantly higher after constant pFSH doses than after decreasing doses (P<0.001). The mean number of CL, embryos recovered and embryo recovery rate with pFSH were higher than with PMSG (P<0.001). ). Chi-square analysis showed that there was a significant difference in the distribution of embryos among various developmental stages (P<0.001) and their quality grades (P<0.005) between two gonadotrophin treatments. The semi-laparoscopic method of embryo collection and transfer method increased the embryo collection, transfer and survival rate compared with surgical. Morula stage of embryos produced higher pregnancy rates (90.9%) than early morula, early blastocyst and blastocyst. Significantly higher pregnancy rates (77.3%) and embryo survival rate (36.0%) were observed when embryos of Grade 1 were transferred than Grade 2. Increased pregnancy and embryo survival rates occurred in recipient ewes having CL 3+ compared to CL 1 and 2. The study fulfilled the objectives successfully, with the development of protocol of controlled breeding system (oestrus synchronization and MOET) in indigenous ewes in Bangladesh, with the birth of live lambs and their survival.