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Improvement of reproductive traits of Moghani ewes using GnRH and eCG administration during estrous synchronization in non-breeding season
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Vahid Vahedi *   , Gholamreza Mardaneh , Azade Boustan |
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Abstract: (1188 Views) |
Introduction: During estrous synchronization, administration of gonadotropins such as equine chorionic gonadotropin (eCG) after stopping progesterone treatment, leads to an increase in rate of ovulation. Also using Gonadotropin Releasing Hormone (GnRH) with eCG may causes an increase in ovulation and litter size in ewe. Therefore, the objective of this study was the improvement of reproductive performance of Moghani ewes using GnRH and eCG administration during estrous synchronization in non-breeding season.
Materials & methods: In the current study, a total of 200 ewes within 2-5 years old and weighting 70 kg in completely randomized design were allocated into two groups (100 ewes/group). This study was performed in the non-breeding season under natural photoperiod environment. In order to synchronization estrous of cycle, all ewes were treated for 14 days with a controlled internal sponge device (CIDR). Ewes in first (control) and second (eCG/GnRH) groups were intramuscularly injected 400 IU eCG and 400 IU eCG with 2.5 ml GnRH respectively, after sponge removal time and then the ewes were mated with Moghani rams. After parturition, reproductive traits were calculated in each group. The numbers of lambs born per ewes and weight of each lamb were recorded at lambing time as well. The reproductive parameters were analyzed by ProcGenmod using SAS 9.2 in completely randomized design. The means of all reproductive traits were compared by using Chi-Square test. Born weight of lambs data were analyzed using the GLM procedure and P<0.05 was considered as the significant level.
Results: The results showed that there was no significant effect of hormone treatment on the estrus response rate, pregnancy rate and lambing rate (P>0.05) in non-breeding season. Control group had lower fecundity rate (72%) than the treatment group (92%). In eCG/GnRH group, percentage of prolificacy was significantly different (P<0.05) compared with control (110.8% vs 124.3%, respectively). Twinning rate in eCG/GnRH groups was greater (P<0.05) than the control (21.6% and 10.6% respectively). The birth weight of lambs at parturition was not affected by hormones treatments (P>0.05).
Conclusion: Overall, the combined injection of GnRH and eCG caused improvement of the reproductive performance in the Moghani ewes compared to the injection of only eCG in the non-breeding season and it can be affordable in farm breeding conditions. |
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| Keywords: eCG, Estrous synchronization, GnRH, Moghani ewes, Reproductive performance |
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Full-Text [PDF 791 kb]
(377 Downloads)
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Type of Study: Research |
Subject:
General
Received: 2025/08/23 | Accepted: 2025/10/2 | Published: 2025/10/2
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