Comparative Susceptibility of Donkey and Horse Sperm to Liquid‐Storage Temperature
Pilar Vallejo‐Soto, Antonio González Ariza, Blenda R. N. Vilela, Carlos Montero‐Palma, Rocío Rodríguez González‐Miranda, Verónica Pérez‐Aguilera, Francisco Crespo‐Castejón, Manuel Hidalgo, Jesús Dorado, Isabel OrtizABSTRACT
Preservation protocols for donkey sperm are based on those developed for horses, despite potential interspecific differences in cooling tolerance. This study compared horse and donkey sperm during long‐term storage at 5°C and 17°C. Ejaculates from four stallions and four jacks ( n = 16) were centrifuged, resuspended in skimmed milk‐based extender, and stored at both temperatures. Sperm motility, plasma and acrosome membrane integrity, and morphology were evaluated after 1, 2 and 7 days. Fresh semen parameters showed no interspecific differences ( p > 0.05). At 5°C, donkey sperm showed reduced motility and membrane integrity from Day 1, whereas horse sperm parameters remained stable at both temperatures up to Day 2. After 7 days, horse doses stored at 5°C maintained significantly higher quality. In conclusion, donkey sperm was more sensitive to storage at 5°C than horse sperm, highlighting the need for species‐specific preservation strategies.