The aim of the present study is to compare two estrus synchronization by CIDR and sponge on ewes along with PMSG various amounts in reproduction season. 56 Baloochi breed ewes (45.8 ± 1.3 kg of BW) were divided into two experimental groups. In first experiment, 28 heads of ewes were divided into four groups (n=7/in each group).Estrus synchronization ewes group received CIDR for 14 days. During CIDR exit, four groups received 1 milliliter normal saline serum, 150ml, 300ml, and 450ml international PMSG unit for the first, second, third and fourth group by injection respectively. In the second experiment sponge was used instead of CIDR. 40 hours after injection of PMSG, 6 rams entered the flock. The observed results in the first and second experiment showed that the rates of multiparous, multiple birth and lambing in those groups which received 450 unit PMSG were higher than the other groups (p<0.05). There was not any significant difference between both groups in estrus synchronization (p<0.05). These results suggest that 450 IU PMSG was more effective in increasing Multi birth rate in the Baloochi ewes in breeding season.

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