Estrus synchronization protocols in Blackbelly sheep in tropical region: prostaglandin and male effect

Estrus synchronization protocols may include reproductive hormones or management practices, with differences mainly in relation to costs, labor, number of managements, and time until estrus manifestation. This study aimed to evaluate estrus synchronization protocols in sheep using prostaglandin or male effect in a tropical climatic region. Three estrus synchronization protocols were evaluated in 60 adult Blackbelly sheep, including 1) 150 µg intramuscular prostaglandin D0 and D7; 2) 30 µg vulvar submucosal prostaglandin D0 and D7; 3) male effect: ram introduction. After the last administration of prostaglandin (intramuscular or vulvar) or introduction of the male (male effect), a ram with ink in the chest was introduced, and the females were monitored for signs of estrus every 24 h. Data were tabulated and subjected to descriptive statistical analysis. Within 48 h, 70–80% females that received prostaglandin, regardless of the administration route, showed estrus. Both protocols with prostaglandins manifested estrus in 100% ewes within 72 h. In the male effect group, 50% ewes showed estrus within 48 h. The other 50% manifested estrus after 72 h, with 30% ewes between 96–144 h. In conclusion, regardless of the synchronization protocol, all ewes manifested estrus within six days. The male effect showed a higher interval in synchronization up to 144 h. Protocols with both intramuscular and vulvar submucosal prostaglandin administration resulted in estrus manifestation in all sheep within 72 h. Vulvar submucosal administration of a reduced dose is laborious and reduces hormone cost.