When it’s time to breed your mare, what method do you choose? Live cover? Or artificial insemination with semen that’s been chilled, frozen, or … air-dried? The idea isn’t as far-fetched as it might seem: Argentinian researchers have recently developed a protocol for storing equine sperm by air drying it. Easy to obtain and manage, they’ve determined that air-dried sperm can be kept for up to four weeks before being used for embryo production.

“This is a preliminary study in a nonconventional method of sperm conservation, which may have such advantages as preserving sperm when cryopreservation is not possible, or avoiding transmission of venereal viral diseases,” said Ana Alonso, PhD, of the Department of Theriogenology in the Institute of Investigation and Technology in Animal Reproduction at the University of Buenos Aires’ Faculty of Veterinary Sciences.

Alonso and her fellow researchers compared the embryos they produced using cooled semen stored up to 28 hours and air-dried semen stored for two, 14, or 28 days. All embryos were produced via intracytoplasmic sperm injection (ICSI).

They found no differences in the quality of sperm DNA or the activation of the oocytes (although embryo production itself was slightly higher with cooled semen), said Alonso. What’s more, the success rate was just as high whether the dried sperm had been stored two days, two weeks, or a month