Semen Processing - No Centrifugation
All semen processing steps are described in the laboratory handout on Cooled Semen Preparation. The routine procedure for cooled semen extension is to add 1 part semen to 3 parts extender. This is best done using a graduated cylinder and extender that has been prewarmed to the temperature of the semen to avoid cold shock damage to sperm. In the example below, 5 ml of semen (37°C) has 15 ml of extender (37°C) added for a final volume of 20 ml. The graduated cylinder had also been warmed to 37°C in an incubator.
Semen = 5 ml
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Semen 5 ml + 15 ml extender = 20 ml
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While this is the easiest procedure for intial extension of semen, if the initial semen concentration is less than 80 X 106 sperm/ml then the final insemination volume will be greater than 50 ml.
- If semen is 80 X 106/ml
- Insemination dose of 1000 X 106 sperm is present in 12.5 ml of the ejaculate.
- Adding 1 part semen to 3 parts extender would then be:
- 12.5 ml + (3*12.5 ml) = 12.5 ml+ 37.5 ml= 50 ml
Insemination volumes of 50 ml or more are known to have reduced fertility in mares. An ejaculate with a concentration of 80 x 106 or less then needs to be concentrated with centrifugation before proceeding.
