Effect of the method of estrus synchronization and PMSG dosage on estrus and twinning in Ethiopian Menz sheep

Theriogenology;38(4): 727-734

Examines the effect of two dosages of PMSG on the onset of estrus and twinning in an African breed of sheep whose estrus was synchronized using either intravaginal progestogen sponge or prostaglandin F2 alph. Table 1 summarises the results of the study. Most ewes (>75 percent) manifested estrus within 72 hours of either sponge removal or the second PGF2 alpha injection. The time to estrus was significantly (P=0.025) shorter in prostaglandin than in progestogen-synchronised ewes, but there was no difference within the synchronisation groups. A few ewes (2 to 4) per group did not conceive to the synchronised estrus, and returned to service, but there was no difference between groups. Twinning and, therefore, the total number of lambs born increased with the PMSG dosage but did not reach overall significant levels between groups.