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Founder in Horses
Wednesday July 28, 2010 It is that time of year, summer heat and long days in the Peace River Region cause fresh green grass to grow at an alarming rate. All of our horses whom we have fed on dry hay most of the long winter are gorging themselves on the welcomed, tasty forage. Our fertile soils and abundant grass also comes with a price, it can easily founder our horses.
Founder, also called Laminitis, is a very common condition. The term ‘Laminitis’ broke down is ‘Laminae’ meaning the ‘nail bed’ or dermal tissue which attaches the hoof to the coffin bone of the foot, and ‘itis’ meaning inflammation. I usually tell clients it is like the Velcro between the hoof shell and the bone in the foot. This tissue is microscopically folded and branched, and if the laminae from one hoof was flattened out it would have the same surface area as a four by eight foot sheet of plywood! This large surface area bond is what is damaged with founder or laminitis.
Causes of founder are numerous but the most common reason we see is obesity or overeating. This type is very common in our easy keeping horses like ponies and small breeds. It can also be related to insulin resistance and a diabetic like condition we call metabolic disease.
Another cause is toxaemia. Toxaemia is a condition where there are poisons or toxins in the blood stream. This can occur after conditions like pneumonia, pleurisy, diarrhoea, colic, and uterine infections. Bacterial, viral, plant, chemical, and fungal toxins all have the ability to cause founder. The laminae are starved from blood and die as a result of toxins constricting the blood vessels to the feet.
Hormone disturbances may also result in founder. Thyroid problems have been implicated and founder is very common with Cushings disease ( where the adrenal glands produce too much).
Other things that have been implicated are traumatic founder caused by to much weight bearing by one limb or concussion.
There are many myths on the causes of founder which include cold water consumption, allergies, pregnancy, and estrus (in heat).
Symptoms of founder are very typical but can occur with a range of severity. Usually what is noticed in general is a very tender footed gait and saw-horse stance. They walk like they are walking on hot coals and stand with forelimbs extended out in front of the body while shifting weight to the rear limbs. The hind limbs are ‘camped under’ the body because the horse is distributing weight onto the less affected hindlimbs. Horses bear 65% of their body weight on their front feet and therefore usually founder is worse on the front end. They usually have increased pulse to all feet with heat on palpation of the hoof. They may be so severe that they may not want to even stand on their feet. Severe, acute founder can be devastating and is extremely painful. It is like slamming your fingernail in the car door and then attempting to stand on it. However founder may also present as very mild episodes which occur over a long period of time and are barely noticeable. This is what I call chronic laminitis and is usually the fat, easy keeping ‘pasture potato’. These chronic horses usually exhibit ‘fever rings’ on the hoof wall and when looking at the bottom of the foot have a stretched white line we call seedy toe.
Depending on the degree of founder the breakdown of the bond between the hoof and coffin bone can cause a couple things. First, because the coffin bone is almost suspended in mid air by the hoof shell it has a tendency to want to sink. Secondly the flexor tendons which attach to the back aspect of the coffin bone pull or rotate the coffin bone around. The amount that each one of these happens determines the prognosis (the likelihood of the lameness resolving) and can direct what we can do as far as treatment. Doing x-rays of the feet can give us an objective measurement of the severity of the founder.
Treatment can include anti-inflammatories, hot and cold therapy, soft footing, cushioning the frog and sole support, corrective trimming and shoeing. The initial cause of the founder can be looked at but often it is too late to correct the primary source of the problem. A good farrier is crucial when considering long term management of these patients. A shortened, rolled toe, frog and sole support, with minimal heel removed will help decrease the rotational and sinking forces. Farriers will work with your vet to determine what type of trimming will be necessary to minimize the long term damage in your horse’s feet.
The most common way you can prevent founder is keeping your equine friends in reasonable body condition. It is far too easy to turn these horses out into their ‘natural’ grassy environment and just let them be horses. Unfortunately we have to be able to recognize when these guys are too fat and get them on a diet. Some horses, due to their genetic makeup cannot be out on grass that much. Jenny Craig pens or grazing muzzles are a must with some of these guys that ‘get fat on fresh air’. If you have any questions about founder or any other diseases, please contact one of our veterinarians for more information.
Dawson Creek Veterinary Clinic (2002) Ltd 238-116 Ave Dawson Creek, BC V1G 3C8
(250) 782-1080
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