Artificial insemination with frozen semen in donkeys

Abstract

Donkeys (Equus africanus asinus) have been used for years for work in rural areas, for transport and currently are also used for mules (Equus mulus) and milk production. The risk of extinction of some local breeds has stimulated the use of reproductive biotechnologies such as semen cryopreservation for artificial insemination (AI). The objective of this work is to describe the cryopreservation protocols alternatives for donkey semen, the critical points in jennies management and insemination techniques; and to describe briefly the state of the art for this biotechnology in donkeys. Reported per cycle pregnancy rates with donkey frozen semen vary between 11 and 61,5%. In vitro studies showed better post-thaw semen quality when temperature stabilization was performed prior to freezing; using lactose-based semen diluents supplemented with donkey colostrum; and semen conditioned in 0,25mL straws. The female factor is a main point in the application of artificial insemination with frozen semen due to the inflammatory response after insemination. Further in vivo studies are needed to clarify the semen-endometrial interaction and potentially develop techniques that contribute to greater efficiency of pregnancy rates per cycle.