A brief history of artificial insemination

In 1780, an Italian scientist by the name of Spallanzani bred a dog with freshly collected semen and later delivered three puppies from the mating. At the time, little attention was paid to the event because selective breeding was not commonly practiced.

Veterinarian checking sperm motility

Both frozen and cooled semen maintain viability and result in AI success.

In 1803, Spallanzani placed dog semen in snow and recorded that the sperm became motionless. When the semen was warmed, the sperm began to move again. Early in the 1900's, artificial insemination (AI) in horses and cows using fresh, diluted semen became widely practiced in Russia and Japan. The driving force behind the development and use of AI was the desire to make wider use of better sires.

Semen extenders or diluters, which allowed semen to be cooled and used within 24 hours, were developed. In the 1930's, the use of cooled semen for inseminating cows and horses began to increase in the United States. However, it was not until 1997 that the American Quarter Horse Association approved the use of cooled semen, giving a major boost to the practice.

More recently, with the perfection of techniques for successfully freezing semen, the use of frozen semen has become increasingly popular.

Using cooled semen

The advantages of using cooled semen include:

• Location of stallion is of little consequence.
• Allows more options to select a stallion with desired pedigree and/or performance traits.
• The stress, costs and danger of shipping the mare are avoided.
• Mare does not have to spend time in a breeding facility.
• Risk of exposure to contagious diseases at breeding and/or boarding facility is avoided.

The disadvantages include:

• Level of fertility of some stallions is lessened when their semen is cooled and shipped.
• An increased number of sperm are required for good pregnancy rates when compared to AI using fresh semen.
• Mare management must be at a highly-skilled level for an acceptable pregnancy rate.
• Cost for equipment, supplies, semen, semen transport and veterinary costs can offset any savings.

Most breeding registries will accept registries associated with cooled, shipped semen and the conception rate is good if the mare is bred within 24 hours of semen collection.

Using frozen semen

The advantages and disadvantages of using frozen semen are similar to those of using cooled, shipped semen.

The advantages include:

• Stallion can be located almost anywhere in the world.
• Choices as to pedigree and performance traits are enhanced.
• Processed frozen semen has a life span of years instead of days and it can be easily shipped.
• The mare does not have to be shipped or kept in a breeding/boarding facility.
• Risk of exposure to contagious diseases is avoided.

Disadvantages that a horse owner should be well aware of include:

• No consistent standards exist concerning how much semen is frozen for a dose, how the semen is sold, the thawing rate or storage temperature.
• Viability may be reduced.
• Requires increased monitoring of the mare.
• Technical skill very important for proper timing and deep horn insemination.
• Depending on the source of the frozen semen, the directions for use may be inadequate or confusing.
• The veterinarian may need to have nitrogen tanks in which to store the frozen semen.
• A dry shipper must be used and the rental fee and length of rental may be confusing or increase the cost.
• Some breeding registries do not accept foals produced by using frozen semen and paperwork requirements differ.
• Some mares may develop a prolonged inflammatory reaction to the semen because there is no seminal plasma in the frozen product.
• Pregnancy rates are generally lower than when using either fresh or cooled semen.

In all cases of artificial insemination, the services of an experienced veterinarian are very important. Proper management of both the mare and the stallion is crucial and significant attention to detail is necessary to achieve an acceptable conception rate.

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If this topic interests you, you will probably also enjoy reading Equine Artificial Insemination Explained. We also encourage you to read The Responsible Horse Breeder prior to deciding if you want to breed your horse.