Alamo Pintado Equine Medical Center, Inc.

To: Peruvian Paso horse owners

Re: Suspensory Ligament Desmitis

Alamo Pintado Equine Medical Center has been treating horses for over 30 years in Los Olivos, California. We see horses of all breeds and of all equine performance sports. We have always seen a large number of Peruvian Paso horses because of our locale to many top Peruvian breeders and trainers in the Santa Ynez Valley and California.

In the last six years we have diagnosed well over 1,000 suspensory ligament injuries in horses associated with racing, jumping, dressage, cutting and endurance events. We have diagnosed approximately 8 Peruvian Paso horses with suspensory ligament injuries during the same time period. Of these 8 injuries in the Peruvian Paso horses, six were determined to be typical overuse injuries and were treated as such at APEMC. Of the other two Peruvian Paso horses that did not fit the typical overuse injury, one was due to being extremely overweight and poorly taken care of and the other horse may have had what has been called degenerative suspensory ligament disease but it was not confirmed with any histologic evidence.

The veterinarians at APEMC have always found it to be curious that this condition of the Peruvian horse has not been described in any equine lameness or surgery text and has not surfaced as a cause of unsoundness in the Peruvian Paso horses that we have dealt with on a daily basis for the last 30 years. On the contrary, we have found suspensory desmitis to be very rare in the Peruvian Paso population that we treat compared to a relatively high incidence in the racehorse, jumper and dressage horses. We feel that these high rates are a factor of footing, training and shoeing problems. We do feel that some of these injuries are related to abnormal conformation in some horses and are not just occupational hazards. Some large breed broodmares that have had numerous foals will often develop a chronic progressive suspensory ligament degeneration and breakdown that is very difficult to treat as long as they remain heavy and continue to carry heavy pregnancies. Once this degenerative process develops it is not possible to reverse and return the suspensory branches to normal with rest or treatment. Weight management in any breed of horse is critical to health and soundness.

I am sure that this condition has been diagnosed and documented in a certain number of Peruvian Paso horses on some farms in the United States, but I have not heard of the numbers and the overall incidence as of yet. We have seen this identical problem in Thoroughbreds and Quarter horses, but these are horses that were poorly conformed and passed the predisposing conformation to their offspring. The simple answer to this problem is to not breed bad-legged horses to bad-legged horses, or to breed any horse with a severe inherited conformation fault. Once that becomes obvious, the problem goes away.

In our experience, the Peruvian Paso, as a breed, is a very tough, durable and sound breed of horse when compared to all the other breeds of horses we see at APEMC. I hope that the excitement and confusion over a small group of isolated horses does not continue to cast irresponsible unwarranted connotations on a very strong and sound breed of horse.

Doug Herthel, DVM Mark Rick, DVM
Greg Parks, DVM Ed Hamer, DVM
Carter Judy, DVM DACVS