Breeding a Thoroughbred to a Quarter Horse: What to Know

American Quarter Horses are known for their strength, versatility and speed. When it comes to short-distance racing, they’re just built for it!

But what happens when you combine the characteristics of the Quarter Horse with the long, lean athleticism of a Thoroughbred? You get an Appendix Quarter Horse - a horse that brings together the best traits of both breeds. These horses will excel on the racetrack and in a variety of disciplines. 

Where to Start: Record Your Thoroughbred with AQHA

Before you get started, there’s one key step: recording your Thoroughbred with the American Quarter Horse Association. 

Here’s what you’ll need to submit:

• The Jockey Club certificate: A photocopy of the front and back of the certificate.  If the certificate is digital, provide a screenshot of the online certificate and ensure that it clearly shows the ownership section. 
• The applicable recording fee.
• An AQHA membership if the owner is not already a member.
• Genetic Testing: AQHA rules require a DNA type to be on file for a Thoroughbred before any offspring can be registered. 
  • A signed statement allowing AQHA to request DNA info from the Jockey Club.
  • If the DNA type cannot be recorded with AQHA, or if the horse does not have DNA on file with the Jockey Club, a DNA kit will need to be ordered from AQHA.
  • All stallions must have a genetic health panel results on file before resulting foals can be registered from breeding’s occurring after January 1, 2015

Once AQHA receives all necessary items, your horse will be assigned a T-number (ex: T0123456). This serves as your Thoroughbred’s AQHA number. A letter is mailed to the owner with this information when the recording is complete. If you are looking at AQHA records, be aware that a T-number doesn’t automatically mean your horse is approved for breeding with AQHA. Sometimes it means it was used to establish a pedigree for another Thoroughbred or for a variety of other reasons.

If you’ve recently purchased a Thoroughbred or are looking to breed your horse to a Thoroughbred, and aren’t sure whether it’s already recorded with AQHA, don’t worry—we’ve got you covered. Just reach out to AQHA, and we’ll look up the horse for you.

If the horse does have a T-number, updating the ownership is simple!  Submit a copy of the Jockey Club certificate showing you as the new owner, include the applicable transfer fee, and AQHA will update the horse ownership record.

Registering an Appendix

So, what happens when you breed a Quarter Horse with a Thoroughbred? The resulting foal is registered in the Appendix Registry. Appendix horses are not limited to any area except for breeding. Appendix horses may only be bred with permanent-numbered Quarter Horses to produce an eligible foal. You can spot an Appendix horse by their AQHA registration number, which starts with an "X" (e.g., X0123456).  Keep in mind, a foal resulting from an Appendix-to-Appendix or Appendix-to-Thoroughbred cross is not eligible for registration.

 Appendix horses may advance to a permanent-numbered Quarter Horse status once they meet the qualifications to be advanced. To be eligible for advancement, a horse must first earn a register of merit in either racing or open show division. The horse also cannot have any of the genetic defects as defined in AQHA rule REG109, including parrot mouth, cryptorchidism, excessive white markings, or carry HYPP.  Once advanced, the breeding restrictions are removed.

If you need assistance, don’t hesitate to contact Member Services at 806-376-4811, Monday – Friday, from 8 a.m. to 4:30 p.m. Central.