Oct. 24, 2018
Founder – Laminitis
Full Circle Equine Veterinarians have seen quite a bit of founder in horses this past month. While this is usually encountered more with spring grasses, we inquired as to what might be the causes and preventive methods. Here’s their answer.
There are a number of different causes for laminitis. Generally you worry about it in horses that have high fevers (>103.5°) for more than a day or two. You can also see it in horses that have an injury in one leg and are putting extra weight on the others to compensate (this is usually called mechanical laminitis). The extra weight stresses the sensitive laminae of the foot and can, over time, cause the coffin bone to rotate and the horse to founder.
What we are seeing most this time of the year is a metabolic founder, where horses that are slightly insulin resistant get turned out on pastures with lots of grass and for some reason the carbohydrates cause inflammation in the feet and can lead to founder. Ponies are the most common horses we see this in, but it can happen to any breed. All the text books say that you usually see metabolic founders more in the spring and late fall, but the last couple years we've always had quite a number of cases come in around this time of year.
As far as prevention, with the metabolic syndrome, especially it’s important to get your horse examined by a veterinarian at least yearly to see if they may be at risk of being insulin resistant. If they are, you can do things like have them wear a grazing muzzle when out on pasture, or limit the amount of time they get to spend out grazing. Early intervention is incredibly important! So if an owner notices that their horse looks footsore, it’s a good idea to get a veterinarian out as soon as possible. There are certain things we can do to decrease the inflammation (largely stand the horse in ice) that can help prevent permanent damage, but they are only effective in the early stages of the disease. So waiting a few days to start treatment can really change the prognosis.
With the other causes of laminitis, controlling the fevers with cold hosing and NSAIDs (banamine) can be preventative, as well as placing a support shoe or packing the hooves of the non injured legs for the mechanical type of laminitis.
Dr. Eleanor Kellon, VMD, Staff Veterinary Specialist for Uckele Health and Nutrition, has also written about late summer founder. She wrote:
“In the late summer to early fall there is a peak in laminitis cases.... Beginning in late summer there is a rise in the level of the hormone ACTH. This usually peaks in September then gradually declines. For most horses, it causes no problems. If the horse has early Cushing’s disease, a benign overgrowth of part of the pituitary gland, the rise is exaggerated and the high cortisol it causes can induce or worsen insulin resistance. This in turn can cause laminitis if the sugar and starch levels in the diet are more than the horse can easily tolerate.
“Although studies are not consistent on this, some research has shown a rise in insulin that parallels the seasonal rise in ACTH. If the horse already has insulin resistance, this seasonal rise could push the horse over the edge into laminitis.
“If your horse develops late summer or fall laminitis, get your vet involved and test for ACTH and insulin. If very high, especially if the diet is already low sugar and starch, the horse may benefit from the medication Pergolide, at least for part of the year.
“Otherwise, the treatment is meticulous hoof trim/balancing and a very low sugar and starch diet with no hay or feeds over 10% sugar and starch combined. Mineral balancing further helps with insulin action, control of inflammation and tissue healing.”
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