Boar stud laboratory

Good practices when diluting the extender

The extender is the essential product for properly conserving the semen over time. Different criteria can impact your choice of extenders: shelf life, spectra covered by antibiotics, preservation of sperm motility… In any case, and irrespective of the extender, dilution is a key step in the boar semen production process. With the help of Kebb, technical coordinator at GenePro Brazil, this article features the best practices to use in a boar stud for the dilution of the extender.

Follow the instructions on the bag

GenePro boar semen extender

As trivial as it may sound, the first thing to do is to follow the instructions on the bag. First of all, the right amount of water must be used: an extender concentration that is too high or low can have a negative impact on the spermatozoa (poor conservation over time, bacterial development, impact on faster sperm mortality, etc.). It is then essential to have an accurate device that can measure the exact amount of water in your dilution tank. The ideal is to have an automatic water filling system to measure the volume in the tank precisely. Otherwise, a graduated tank is essential.  An approximation of the quantity of water on 200 liter tanks will inevitably have an impact on semen quality.
Next, the mixing/dissolving time must be respected too. A reduction in mixing time usually leaves lumps in the extender. Ultimately, these lumps cannot be used by the spermatozoa: once again this leads to a decrease in quality and therefore the effectiveness of the extender. It is important to ensure that the teams within the laboratory take the time to mix the extender. It is common that in order to save time, the 15 minutes needed for properly diluting an extender are shortened. It is therefore essential to remind teams of the importance of respecting this dilution time.

Also, the amount of powder to be diluted must be weighed accurately. In some cases, the powder does not need to be weighed if the weight of the bag corresponds to the volume of water to be diluted. However, in cases where this powder must be weighed, laboratory technicians must have scales accurate to 0.1 grams.
Ideally, it is preferable to finish the entire bag the day it is opened to avoid any potential contamination of the powder. If not, be sure to reseal the bag until the next time you use it.

Finally, the reverse osmosis-purified water must be heated to the temperature recommended by the manufacturer, usually around 30 degrees. An automatic heating system with temperature control directly in the tank is used to increase accuracy. As explained in the article “the main mistakes when preparing an extender”, it is better to heat this water as late as possible: Avoid keeping it at temperature overnight before the morning of production, to limit the risk of bacterial growth. 
With the right amount of powder in the right amount of heated water and the right mixing time, the chances of the proper dilution of your extender are high!

Production and storage of reverse osmosis-purified water

Osmosis water system

An extender must be diluted with reverse osmosis-purified water. This water can either be bought in cans by the center, or be produced directly in the laboratory in the case of more substantial breeding. This reverse osmosis-purified water production must be supervised by a professional to ensure good water quality. If you would like to know more about the criteria to be analyzed during a reverse osmosis-purified water test, do not hesitate to contact one of the experts at Boars & Semen. In order to ensure efficiency during production days, it is always essential to have a sufficient volume of reverse osmosis-purified water in stock. But beware, this water cannot be kept for too long: it is therefore essential to check the expiration date of the reverse osmosis-purified water previously produced regularly.

Post-production control

After diluting the extender powder with reverse osmosis-purified water according to the manufacturer’s recommendations, it is essential to make a few checks to ensure that there were no problems during production. There are two checks to be made:

  • PH control. Depending on the recommendations of your extender supplier, it is important to check after each tank produced, that the pH of the mixture is within the range indicated by the manufacturer. An extender powder that has had a storage problem will directly impact the pH level. Systematically checking the pH ensures a quality thinner. To monitor your pH, feel free to ask about GenePro’s pH meter. The pH should be between 6.9 and 7.2 so as not to have a negative impact on the spermatozoa.
  • As with pH, the osmolarity of the mixture should also be checked at each production run. For this, you can use the GenePro measuring device. Osmolarity, unlike pH, is variable from one extender to another

These controls generally tend to be neglected by laboratory teams. Feel free to set up a reporting system to ensure that the controls are carried out correctly!

Many problems in a boar pen laboratory are caused by poor preparation of the extender. Do not neglect this step any longer, and with your teams, ensure that the dilution protocol of an extender is properly conducted.
Please contact us or visit our website for more information about GenePro extenders.

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