Estrus synchronization using progesterone+different gonadotropins or flushing+ram effect in the breeding season in sheep

Objective. Konya Merino ewes were used to examine the effect of different doses of eCG or a dose of FSH in a progesterone-based estrus synchronization protocol or flushing+ram effect on fertility in the breeding season. Materials and methods. Ewes were divided into six groups. Estrus of ewes in eCG-300, eCG-500, eCG-700 and FSH-10 groups was synchronized with an intravaginal sponge containing progesterone-derived for 12 days and PGF2alpha injected one day before sponge removal. eCG-300, eCG-500 and eCG-700 groups received 300, 500 or 700 IU of eCG respectively, at the time of PGF2alpha injection while FSH-10 group received 10 IU of FSH with sponge removal. In these four groups, estrus was detected for 5 days following sponge removal. Flushin+ram effect (F+RE) group ewes received dietary supplements for 28 days and ram effect for 14 days before the start of the mating period and were monitored for estrus for 4 weeks later. Control ewes monitored for estrus for two months without any treatment. Results. Birth rate was higher in F+RE group than eCG-500 and FSH-10 group (P<0.05). Litter size was higher in eCG-700 group than F+RE and control groups (P<0.05). Fecundity was higher in eCG-700 group than FSH-10 group (P<0.05). Conclusions. 300 IU eCG at the end of progesterone application was sufficient to induce multiple lambing during the breeding season. However, due to lamb losses originating from multiple births, sufficient lamb production could be achieved without any application evaluated in the study considering weaning rate.