Document Type : Research Paper
Authors
1 Department of Animal Science, Faculty of Animal Science and Food Technology, Agricultural Sciences and Natural Resources University of Khuzestan, Mollasani, Iran
2 Department of Animal Science, Faculty of Agriculture and Natural Resources, University of Tehran, Karaj, Iran
Abstract
Objective: Fertility is a fundamental factor for the profitability and sustainability of sheep breeding companies and is also a valuable selection criterion in genetic improvement studies. The Romanov sheep is one of the best-known breeds worldwide in terms of fertility. Excellent results regarding the fertility of Romanov sheep have attracted the attention of many breeders. It seems essential to apply reproductive technologies to Romanov sheep in Iran, which have shown a seasonal decline in reproductive performance. The application of proper management methods during the non-breeding season to increase economic efficiency, especially in imported breeds, is of high importance. This study aimed to evaluate the effect of using short-term 5-day estrus synchronization protocols with two sponge brands containing different doses of eCG hormone on the reproductive performance of Romanov ewes during the non-breeding season.
Methods: In this study, 90 Romanov ewes aged 2 to 5 years with an average weight of 38.8 ± 1.2 kg were used. The ewes were synchronized for 5 days using either the Esponjavet sponge containing 60 mg medroxyprogesterone acetate (45 ewes) or the Fluorogest sponge containing 40 mg flurogestone acetate (45 ewes). Upon sponge removal, each group was subdivided into three subgroups of 15 ewes each and received 300, 450, or 600 international units of eCG hormone.
Results: The Esponjavet sponge significantly reduced mucosal secretions and vaginal adhesions in grades 1 and 2 compared to the Fluorogest sponge (P<0.05). Fertility, lambing, and prolificacy rates were higher in the group treated with Esponjavet sponge combined with 600 IU eCG (P<0.05), while twinning rate, abortion, and barren ewes were not affected. The highest serum progesterone concentration within 48 hours after sponge removal was observed in the Esponjavet treatment combined with 300 IU eCG. In treatments receiving 450 and 600 IU eCG, estrogen levels at 24 and 48 hours post-sponge removal were significantly higher (P<0.05). Cost-benefit analysis showed that the use of the Esponjavet sponge with 600 IU eCG yielded the highest profitability.
Conclusion: The results indicated that the reproductive performance of short-term sponge treatments from the two similar brands was comparable. Treatments receiving 600 and 450 IU eCG had similar effects on improving fertility. Economically, the use of the Fluorgest sponge is more cost-effective, and 450 IU eCG combined with this sponge can be used to improve reproductive efficiency and economic profit in breeding flocks. However, if the goal of estrus synchronization protocols is to increase twinning rate, the best option is the Esponjavet sponge with 600 IU of eCG.
Keywords
)