Paternity Tests in Horses.

The study investigates the use of parentage tests to accurately determine the lineage of thoroughbred horses, improving the accuracy of horse registries. The tests, based on genetic exclusion principle, led to the update of registration papers of various horses, with a success rate of about 65%.

Background

• When a thoroughbred mare breeds with two different stallions, the resulting foal is registered under both stallions. This method of double registry is disadvantageous, particularly in maintaining accurate pedigrees.
• The Jockey Club, responsible for the registration of thoroughbred horses in the United States, wants to reduce the amount of double-registered horses. For this, paternity tests were developed in a laboratory setting, aiming to exclude one of the possible stallions as a parent.

Paternity Tests

• The paternity tests are based on the principle of genetic exclusion. The aim is to prove that a particular horse or horses cannot be a parent of the horse in question.
• After conducting the tests, it was realized that in about 65% of the cases, one of the potential stallions could be excluded as a parent.
• The use of these tests led to The Jockey Club authorizing a change in the registration papers of multiple double-registered horses. The changes included the removal of the unqualified stallion and the retention of only the qualified stallion on their records.

Financial Support

• The research and testing process was supported financially by grants from The Jockey Club, The American Shetland Pony Club, and The California Thoroughbred Breeders Association.

Conclusion

• The findings from the paternity tests have led to an advancement in establishing accurate lineage information in horse pedigrees by excluding potential unqualified parents. This has resulted in a substantial reduction in the number of double-registered thoroughbred horses, maintaining integrity in pedigree records.