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The goal of this study was embryo transfer in Kivircik ewes synchronized by MAP sponges in and out of the breeding season and to investigate the effects of season on embryo transfer.
12 recipients and 14 donor Kivircik ewes were used in the season and 13 recipients and 14 donors were used out of the season. MAP sponges were administered to the ewes for 14 days. The recipient ewes were injected with 500 IU PMSG 24 h prior the withdrawal of the sponges and the donors were injected with 1500 IU PMSG to achieve superovulation 36 h before the withdrawal of the sponges by IM route.
After the removals of the sponges heat detection was carried out by teasing rams every 12 hour. Recipients on heat were injected by 500 IU hCG immediately. Donors were injected by 1000 IU. hCG after heat detection and mated under control. Donors were mated every 12-hour until the estrus behaviors disappear.
Embryos were collected by uterus flushing from the donors 7 days after the onset of oestrus. The embryos were evaluated and the ones suitable for transfer were transferred to the uteri of recipients. Recipient ewes were kept undercontrol and lambing was recorded. Fertility rates were determined according to delivery rates.
Recipient ewes had an oestrus rate 91.67% and 53.85% respectively in and out of the breeding season (P<0.05). This rate was 100% in both donor groups. Oestrus behaviors began earlier (P<0.00l) in recipients after the withdrawal of sponges in season (36. Hour 66.66%) than out-season (48. Hour 46.15%). Similarly most of the recipients (83.33%) were on heat at 36lh hour in the season. This rate was highest (53.85%) at 48th hour out of the season (P<0.001).
In the season 1.75 ± 1.71 and out of the season 2.3 ± 1.49 corpus luteum were observed on the ovaries of the recipients. These values were 4.43 + 2.82 and 4.57 ± 4.19 in the donors.
In the season 1.71 + 1.83 embryos and out of the season 1.86 + 2.61 per ewe were recovered from the donors by uterus flushing. In the season total 24 embryos were recovered from 14 ewes and 20 of these (83.33%) were transferable. Out of the season total 26 embryos were recovered from 14 ewes and 21 (87.50%) of these were transferable. In the season 14 of the recovered embryos were transferred to the uteri of 7 recipients and out of the season 20 embryos were transferred to 13 recipients. At the end of the gestation 3 of 7 ewes (42.86%) in the season and 3 of 13 ewes (23.07%) out of the season delivered (P>0.05). Only one ewe from the out-season group had twins (7.69%).
At the end of the study, since the synchronization (P<0.05) and ovarian findings and birth rates gave better results in the season (P>0.05), it İs concluded that embryo transfer will be more successful in the breeding season.