Evaluation of Short Term Extenders

Semen extenders have been widely used since artificial insemination are practiced all over the world. Having that said range of semen extenders are coming out of the market giving out a specific advantage over the other. A lot of technician and practitioners are asking on what kind or how long they should have been using for their operation.

It is important to know that all extender has a basic composition allowing the spermatozoa live longer to a certain extent. There are factors affecting the viability of semen doses throughout the extension days. One factor is the kind of extender you are using. A short-term extender which is commonly used on commercial farms for example may vary and perform differently to seminal quality, collection and extension procedure to storage condition.

Magapor, a Spanish company known to produce a wide range of semen extender has a control and monitoring the seminal quality of more than 9,000 boars. Their RND laboratories receive and perform analysis of semen most important viability parameters such as motility, concentration, morphology, HOST, acrosome integrity, pH/osmolarity, and microbiology. These allow Magapor to continuously improve their extenders throughout the years.

A short trial conducted at Magapor laboratory comparing Biopig and a local customized BTS is giving us an example of what to look for a quality extender.

Doses were prepared and kept at 15 to 17ºC. To compare these extenders, several parameters were performed in the laboratory where pH, osmolality, motility, movement quality, membrane integrity (hypoosmotic swelling test, SHOST) and acrosome integrity (osmotic resistance test, ORT) were evaluated at 2nd and 5th day after extension.


Extender pH Osmolarity
Biopig 7.29 331
BTS 7.32 325




These results showed a significantly lower total and progressive motility in the BTS sample compared with Biopig samples.

Despite the membrane and acrosome integrity are within the range at 2nd day, lower results have been observed in BTS at 5th daily and this results showed significant differences compared to Biopig. Biopig showed best results in all parameters while BTS gives poor results and should be discarded if used after 2 days. 

Although motility of both extenders maybe acceptable in-farm other parameters are not simply observable through an ordinary microscope. The hypoosmotic test and osmotic resistance test are true parameters of how an extender protects and ensure the viability of spermatozoa. 



Magapor Short Term Extender Evaluation report www.magapor.com


Published by: plaridel
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