Thawing Frozen Swine Semen


Equipment Needed

  • Extender – Modena or SGI Ready Made
  • Distilled Water
  • Graduated plastic insemination bottles – minimum of 80 ml capacity
  • Sterile glass or plastic container for mixing extender – 1-2 liter capacity
  • Sterile glass or plastic beaker for pouring extender into bottles
  • Water bath OR sink to thaw straws
  • Timer with minutes and seconds
  • Tongs or large tweezers
  • Paper towels
  • Scissors
  • Thermometer – Celsius or Fahrenheit


  1. Warm the bottles of extender to 20° C or 68° F.
  2. Heat the water bath or sink of water to 50° C or 122° F.
  3. Place liquid nitrogen tank next to the water bath/sink.
  4. Quickly remove one straw at a time from the nitrogen tank with tongs and place in the water bath for 45 seconds.
  5. After 45 seconds remove the straws of semen from the water bath. Make sure to dry the straws well; any excess water that gets into the semen will kill the sperm cells.
  6. Cut the straw below the bead and place the open end into the extender bottle.
  7. Allow air bubbles in the straw to gather at the closed end of the straw; once the air bubbles have all gathered, cut the closed end.
  8. Put the cap on the bottle and gently shake the bottle with the semen and extender in it.
  9. Place the extended semen in an insulated container with warm gel packs.
  10. Use the semen as soon as possible; do NOT use past 1 hour of thawing for maximum conception rates.


Single Insemination

Gilts     29-32 hours

Sows    33-36 hours


Double Insemination

Gilts    24-28 hours (1)

30-34 hours (2)

Sows   28-32 hours (1)

34-40 hours (2)

The above times are hours after the sow or gilt first exhibits standing estrus.

Handling Extender

The SGI freezing process is performed using Modena Extender due to its past and present success in our freezing process. Please have Modena Extender or SGI Ready Made’s on hand for the thawing process; both available for purchase from SGI. Extender for thawing needs to be at 20° C/68° F. Warming or cooling the extender may be necessary to achieve this temperature.


Ready Made Extender

    Upon arrival, place Ready Made Extenders in a freezer (-20° C) for future use. Extenders expire 6 months after production day and the bottles contain the day of expiration.To thaw, set the Ready Made Extenders out at room temperature overnight.


Modena Extender

    Prepare SGI Modena Extender as directed on the package and keep at 35° C. Pour 80 mL of extender into graduated plastic insemination bottles, which can be purchased from SGI. The extender is now ready for use or may be stored in a freezer for 6 months.


Semen Analysis

You may analyze the quality of the semen in the straw that was just thawed. To do this, remove a small sample of the extended semen and place in a small sample tube, small sealed container or Ziploc bag.

Make sure to warm this sample for 30 minutes prior to analyzing. To warm, microwave a gel pack until it is warm to the touch of the inside of your wrist and place the sample on top of the gel pack in a small closed environment. A Styrofoam container or cooler will work.

While the sample is warming, insemination needs to be taking place. Frozen semen viability decreases over time and should not be used passed 1 hour of thawing. When analyzing the sample, make sure to use both regular slides and caffeine slides. This helps to accurately estimate the cells potential as it would be if located in the reproductive tract. When analyzing frozen semen, samples with 40% or more live cells is normal.


If you have any questions regarding thawing frozen swine semen, please contact an SGI representative at 800.247.3958 or email


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