Chilled Versus Frozen: Which Semen is Best for Your Mare?

When deciding between chilled and frozen semen, there are many things to consider, including the suitability of both mare and stallion, the cost, the location of the stallion in relation to your mare, and the success rate of your chosen veterinarian.

Chilled Versus Frozen: Which Semen is Best for Your Mare?

If the stallion you’ve chosen is located more than 24 hours away by plane, the decision to use frozen semen is made for you. While, typically, chilled semen has a higher success rate, the importance of quality genetics from an international stallion may be a better option for your breeding program.

However, if you’re still deciding between chilled or frozen, here’s what you should consider…

Mare and Stallion Suitability

Artificial insemination (AI) often represents a higher cost than live mating and requires a competent veterinarian who can successfully collect, handle and utilize the stallion’s semen. That being said, there are many benefits to AI. Foremost, is the ability to time insemination with ovulation.

When considering AI, you first need to determine whether both stallion and mare are suitable.

For the stallion, this involves:

  • Breeding soundness examination
  • Semen evaluation
  • Prior insemination success with his frozen semen  (N.B. up to 80% of stallions that have been frozen shouldn’t as their sperm doesn’t cope)

For the mare, this involves:

  • Breeding soundness examination
  • Consideration of her age and breeding history
  • Breeding tract health


Most often, the use of frozen semen is more expensive than chilled semen. This is due to a number of reasons. Success rates with frozen semen can range from 0-70%, with the accepted international standard at only 70% for the first cycle.

Frozen semen also has a very short life span, so the timing of the insemination procedure to your mare’s ovulation is critical to success. Often, mare owners will need to account for multiple attempts when using frozen semen.

Your Veterinarian

Last, and certainly not least, the success of using either chilled or frozen semen largely depends upon the skill of your veterinarian who is responsible for accurately predicting ovulation and managing the insemination procedure.

The decision as to which veterinarian you use should be made carefully. At Exclusively Equine Veterinary Services, conception rates of over 85%  frozen semen have been achieved at our purpose-built breeding center.


  • Dr Louise Cosgrove

    The founder of Exclusively Equine Veterinary Services, Louise is driven to support horses in their recovery from injury or illness. A graduate of the University of Queensland, with international equin...

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