الفهرس 
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Abstract
This study investigate the effect of four synchronization protocols on eighty two cross-breed ewes, where these ewes randomly assigned to five groups and each group received 1 of 5 treatments: (1) P4 (2) PGF2α (3) OVS (4) PRID (5) control treatments, and the results revealed that all OVS-treated ewes failed to show estrus but only one ewe of the control group showed estrus. Pregnancy and lambing rates were greater (100%) in PGF2α and halved-PRID for 8 days than the other treatments where the whole-PRID for 14 days recorded the lowest (33.3%) pregnancy rate. The highest prolificacy (1.75) was recorded with whole-PRID for 6 days whereas, the lowest (1.0) prolificacy was recorded with PGF2α and halved-PRID for both 8 and 14 days. So we concluded that. - All synchronization protocols of the present study except OVS had a positive effect on pregnancy and lambing rates during the non-breeding season. -The current study suggest that for more economical estrous synchronization under field conditions, the whole-PRID sponge could be split into two and used successfully to achieve high pregnancy and lambing rates. - Short-term sponge treatment was economically effective as long-term sponge treatment in crossbreed ewes out of breading season.