A lot of attention has been directed to bacterial endotoxins, MMP enzyme activators, and fructan or starch fermentation as factors in laminitis, but how much are they really involved?
By Eleanor M. Kellon, VMD
With laminitis, it is usually hormones, not the hind gut.
In the “horse broke into the feed bin” scenario, too much starch reaches the hind gut where it is fermented to lactate. A significant acidosis develops, which weakens the lining, and allows bacteria, bacterial endoxins, and other factors to enter the circulation.
The same lining damage and bacterial invasion happen with experimental fructan overload, colic/colic surgery, intestinal infections like Potomac Horse Fever or Salmonella, colitis, and uterine infections from retained placenta. These horses have SIR – systemic inflammatory response. They are obviously very ill with dehydration, fever, elevated white count and, usually, diarrhea. In fact, most of these horses are in hospitals.
When laminitis occurs without the horse being seriously ill, and with no overconsumption of grain, there is at least a 90% chance the cause is high insulin from equine metabolic syndrome (EMS), pituitary pars intermedia dysfunction (PPID), or late pregnancy.
Why is this important? The focus in treating endocrinopathic laminitis should be on lowering insulin, not the hind gut, but many supplement sites to this day talk about hind gut factors – and, of course, sell stuff for that. There is even dangerous advice, like suggestions to feed alfalfa because it does not contain fructan when alfalfa is a laminitis trigger for many horses.
The bottom line here is that unless the horse is obviously also ill, you should be focusing on insulin, not the hind gut. For more in-depth information go to http://www.ecirhorse.org, especially the 2017 NO Laminitis! Conference proceedings, specifically: Tiered Management Approach to EMS and PPID, Endocrinopathic Laminitis: How is it Different? and Acute Care for Endocrinopathic Laminitis, as well as,Inflammation in Equine Metabolic Syndrome (EMS).