Techniques for Cooling Equine Spermatozoa

Collect semen
Save aliquot to evaluate sperm concentration and initial motility
Dilute remaining semen 3:1 (extender:semen)
Determine the concentration of sperm and evaluate motility
Dilute semen further to 50 million sperm/ml if possible (50 x 10^6 sperm/ml)
Place 1 billion sperm in storage vessel (plastic tube or bag)
- this is an insemination dose for cooled semen
Cool semen slowly over at least 2 hr to 5°C in the refrigerator or use Equitainer

cool semen by placing the tube of sample in 200 ml of water (same temp as semen) and putting in refrigerator

Place the tube of semen in the beaker into the refrigerator. Be sure that the temperature does not fluctuate in refrigerator.

Fill a cooled semen transport data sheet. This sheet should contain information about the ejaculate volume, motility, sperm morphology, extender, amount and volume of semen per insemination dose. (Example of UW Cooled Semen Transport Sheet, word, pdf).
Preliminary trials should always be done to ensure sperm from a particular stallion will survive the cooling and storage process. You may need to try several extenders if a stallion's semen does not cool well in the extender you first choose to test.