Reproduction in donkeys

European donkey breeds, including Spanish breeds, are endangered due to rural exodus and the mechanization of agricultural work. In this context, assisted reproductive technologies (ARTs) offer a key
tool for preserving genetic diversity and improving reproductive efficiency in this species. However, social, ethological, anatomical, and physiological differences between donkeys (Equus asinus) and horses (Equus caballus) hinder the direct extrapolation of horse protocols. The territorial behaviour of males, differences in social structure, the cervical morphology of females, and the uterine post-breeding response, among others, condition the practical application of horse techniques. Among ARTs, artificial insemination with fresh or cooled semen is the most widely used, while the use of cryopreserved semen, embryo transfer, and in vitro embryo production still show technical limitations and variable results. Advances in the adaptation of these technologies to the donkey species represent
a crucial opportunity for the conservation of native breeds and for the sustainable use of their productive and genetic potential.