The evaluation unit of the University of Extramadura (UEx) has registered the patent for a procedure that allows up to a 15 percent reduction in the post-freezing mortality of equine sperm. In addition, allowing this protocol to be successfully applied in half of the stallions that before was impossible to freeze, as reported by the UEx in a communication sent to the Efe (Spanish news agency). The freezing of equine semen allows the preservation of the genetic characteristics of a stallion, including after its death, and is also

an effective tool to encourage collection that can cross national and international boundaries at the time of inseminating mares. Until now, the most widely used procedure has been glycerol, a substance that protects against damage that could result in freezing and acts in both the external and internal structures of the cell.

Despite its advantages, this and other procedures have the disadvantage that the survival rate in the process of freezing and thawing can reach to 50 percent, including in some cases reaching only up to a 5 or 10 percent survival of the spermatozoa, thus preventing insemination.

The researchers of the equine reproduction laboratory of the University of Extramadura have developed a new formula for freezing that allows a 15 percent survival.

As explained by the original author of research, Fernando Peña, "a straw or pellet of horse semen can freeze up to 200 million spermatozoa, an average of 50 percent of them survive.

"If we increase this new procedure by 15 per cent - he propounded -, we would be talking about 30 million more spermatozoa that survive the process, which greatly facilitates the process of artificial reproduction".

The changes made not only improves the average, but also reduces the variability between stallions, "before now, there had been in 20 per cent of horses that we could not freeze semen, and with this technique it reduces this figure by half", emphasized Peña, who reported that the new diluent is registered as a patent and has been christened "Caceres".

He also stressed that in the context of pure breed farms, the horse is one of the animals where it is more difficult to guarantee the survival of spermatozoa, compared with cattle, where this procedure is relatively easy.