How to thaw frozen semen

First, check the paperwork. Every stallion freezes and thaws differently, and whoever froze the semen will usually send thawing instructions for that stallion. Follow those. What follows is a standard routine for when there are no instructions at all.

1. Prepare a 37 °C water bath

1. Warm a small foam cooler with hot water so the walls take up the heat, then empty it.
2. Run tap water to 37 °C, checked with a digital thermometer, and let it settle.
3. Fill the cooler about half full. A dedicated thaw unit makes this step easier and more consistent.

2. Take the straws out of the tank

1. Roll the liquid nitrogen tank right up to the water bath.
2. Know how many straws make one dose before you open the tank, so you never thaw more than you need.
3. Identify the straws quickly and lift out only what you need.
4. Drop the canister straight back into the tank so the remaining straws are not warmed.
5. Drop each straw into the water at once and leave it for 3 to 5 minutes.

Wear cryogenic gloves and eye protection when handling liquid nitrogen.

3. Handle the thawed straws

Water and semen must never meet. For each straw:

1. Lift it out and dry it thoroughly with a paper towel.
2. With a straw cutter, cut off the end opposite the cotton plug. If the straw is sealed with balls, cut either end.

Then either:

• Load the straw into an insemination gun. This is the usual route for single-straw doses.
• Pool several straws into a sterile tube. This saves reloading the gun for every straw. Place each straw in the tube, cut the top end so the semen drains, and tap it if a bubble holds. When the whole dose is in the tube, draw it into an insemination pipette, at least halfway up, so none is pulled out before the pipette is in place.

4. Inseminate without delay

Frozen-thawed semen has a short life. Have the mare prepared and your technician or veterinarian ready before you start thawing, and inseminate to their protocol.

Adapted from Exodus "Thawing Instructions for Frozen Semen" (2009). This guide covers handling and use only; breeding timing, insemination and anything involving medication are for your veterinarian.