Can Laminitis be Inherited?

Q. I just read your excellent article "The Latest on Laminitis" by Karen Briggs. Is laminitis an inheritable disease? What about founder?


A. The terms "founder" and "laminitis" have become somewhat confusing and are often used interchangeably. I suspect that the more accepted definition and distinction is that when the word "founder" is used, it implies that structural damage has occurred between the interface of the coffin bone and hoof capsule as a result of "laminitis." The structural changes include displacement of the coffin bone (rotation, sinking, or both) within the hoof capsule.

Regarding your question about heritability, I have not done any scientific analysis of this--the following is just observations and thoughts. Genetic factors such as a tendency towards obesity, laziness, poor hoof conformation, etc., surely could be inherited. In addition, based on my experience, I suspect that certain other risk factors are inherited that might influence the incidence of laminitis--but these risk factors might be a stretch. For instance, I believe that show Quarter Horses are at higher risk than Thoroughbred racehorses, Morgan mares are at greater risk than Warmblood dressage horses, and Standardbred stallions are at greater risk than Quarter Horses used for calf roping. But is it the breed or the activity (or the degree of inactivity)?

I believe that relative inactivity increases the likelihood of a given horse (regardless of the breed) acquiring laminitis. Is then the breed (using the American Quarter Horse example) responsible for the degree of activity or inactivity? I think so. I believe that horse owners favor (buy or breed) a particular breed for their "inherited" qualities (speed, speed over distance, size and strength, disposition and the relative ease of handling, etc.). This then helps determine the level of athletic activity. I suspect that much of what happens (regarding laminitis) is a function of how a given individual is managed, used, and how often used.

Most folks who acquire Thoroughbreds get them as athletes (halter classes and showmanship are usually not the reasons for acquisition). Similarly, someone acquiring a horse for ranch work is usually concerned about factors other than looks (such as whether the horse can go all day, stops on a dime, and is not easily frightened by change). While he or she might be influenced by looks, the other factors are more important. These hardworking horses don't fit the "classic" profile of the overweight, under-exercised laminitic horse. However, good placing in halter classes (a common career for Quarter Horses) is dependent on a product with "eye appeal," which usually implies little time in the field, lots of time grooming and feeding, overweight, etc.

Today's modern horse (specifically, the companion horse owned by someone who can afford him) is an apartment dweller--overfed, overweight, grossly under-exercised, and usually worked in the equivalent of a spa when worked at all. The everyday physical challenges that a horse is dependent upon to remain healthy have been removed or reduced. This puts the individual at risk for all kinds of failures, including laminitis.

About the Author

William Moyer, DVM

William Moyer, DVM, is the Department of Large Animal Clinical Sciences at the College of Veterinary Medicine & Biomedical Sciences at Texas A&M and is President-elect of AAEP.

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