Founder (Laminitis)

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Bakers Hill Veterinary Hospital
4609 Great Eastern Highway
Bakers Hill
WA 6562

Phone:
08 9574 1061

Bakers Hill Veterinary Hospital’s guide to Founder (Laminitis) 

Click here to download this info as a PDF handout


Laminitis (Founder) in horses and ponies

Laminitis, commonly known as founder, is the second biggest killer of horses after colic. If the condition of laminitis goes on for some time, or there are repeated occurrences, the damage can become irreversible leading to permanent foot pain. In many cases of this severity, euthanasia becomes the only option.

This disease causes pathological changes to the anatomy of the foot and leads to a devastating loss of function. In the foot of the normal horse or pony, the hoof wall and the pedal (coffin) bone are joined together by a finely structured tissue called the laminae. Surprisingly, and despite being able to withstand enormous forces under normal circumstances, these laminae are relatively delicate and easily damaged. In the condition called laminitis, the laminae become inflamed and extremely painful. The attachment between the hoof and the pedal bone fails which allows the pedal bone to be pushed down into the hoof capsule, crushing arteries, veins and other delicate structures and resulting in pain.

 

Symptoms:

The most obvious clinical sign of acute laminitis is lameness. The degree of lameness will depend on the severity of the disease. Additional signs include sweating, elevated temperature, increased pulse and respiratory rate, warmth of the feet, and increased pulses in the arteries at the back of the pasterns. (Occasionally the signs of acute laminitis may be confused for colic).

 Signs of chronic (longstanding) laminitis are:

• rings on the wall of the hoof and elongation of the toe

• the sole of the foot may also drop and become convex

 

Lameness is unlikely to be noticed in the chronic form of the disease unless the horse or pony is experiencing an acute flare-up of laminitis on top of it’s chronic laminitis. In addition, if both front feet are affected (and they usually are) there may be no head bob. Chronically affected horses and ponies are also prone to recurrent hoof abscesses.

 

Causes of Laminitis

Laminitis can occur secondary to two reasonably common hormonal diseases affecting horses and ponies, namely Pituitary Pars Intermedia Dysfunction (PPID) or Equine Cushing’s Disease, and Equine Metabolic Syndrome.

The laminitis that occurs as a result of diet is due to an excess of fructans or non-structural carbohydrate (NSC). This is rapidly fermented in the hind gut and causes over production of streptococcal microorganisms that trigger reactions resulting in laminitis. Improved pasture designed for grazing sheep and cattle is high in fructans that are well tolerated in these species. Horses, particularly ponies have evolved to survive on fibrous plants high in cellulose and are poorly equipped to digest fructans.

 

Management of Laminitis

 

If the predisposing cause of the laminitis is pasture- or diet-related, the following can be done:

• Feed “Founderguard” daily to susceptible horses and ponies grazing spring pasture. This should be started 4 days before being put onto grass.

• Never allow susceptible ponies to graze spring pasture overnight as sugars are more concentrated in plants at night. Instead, confine the pony to a yard and feed a quality grass hay that should be soaked for ½ an hour to reduce the fructan content (do not use this water and do not allow the pony/horse to drink it).

• Feed hay and chaff to fill the stomach prior to turning out for daily grazing. Consider strip grazing or use of a muzzle for part of the day.

• Do not starve overweight ponies at any time for the sake of reducing the risk of laminitis. This may result in hyperlipaemia, a very serious and sometime fatal disease.

• Exercise ponies regularly to lessen the risk of over-condition.

In any horse or pony with laminitis, regardless of cause, dietary management is important and rapidly fermented carbohydrates need to be avoided. This means feeding NO grains and NO grain based hay or chaff (oaten, wheat, barley, rye), choosing lucerne hay/chaff and meadow hay instead. Also avoid high NSC treats such as carrots and apples. Do feed a multivitamin to ensure there are no deficiencies in the diet.

Laminitic feet need support. Supportive shoeing (heart bar shoes, foot pads) is ideal, or at least regular trimming (every 4 weeks) to keep the toe short. Provide a deep sand yard to support the sole.

In the acute phase of laminitis cryotherapy is very useful (placing foot in an ice bucket, or at the very least regular cold hosing of the feet).

Often acute episodes need medical intervention in the form of pain relief as well.

 

A little more information on Non Structural Carbohydrates (NSC) and fructan - the bad stuff for ponies!

 

The level of NSC at any given time for a given species of grass cannot be taken out of context from the environmental conditions that produced it. Pasture can change dramatically with cold nights and sunny days. Below 5 degrees Celsius all night is the danger period. With cloudy days the sugars are lower but the nitrates are higher. You should be most concerned when the nights are repeatedly under 5 degrees Celsius with nice sunny days.

High NSC’s in grass encourages animals to eat it and hence spread the seeds.

Overgrazing and reducing irrigation and fertiliser increases fructan concentrations.

Clover is generally lower in NSC but clover runners are full of starch. Dandelions, wild oats and plantain have more fructans than grass and are high in NSC. Native grass has ½ to 1/3 of the NSC’s of improved grasses. Saltbush is good for protein and low in sugars.

The forage industry is driven by the needs of the dairy/cattle industry. Pasture grass is usually selected for grazing cattle and it generally has a high sugar & fructose content. It grows for longer, is drought tolerant, better for silage, has better regrowth properties, winter hardiness and palatability. But… a horse is not a cow! Cows are foregut fermenters and NSC’s are utilised before it hits the stomach. Horses are hind gut fermenters and the NSC’s hit the small intestines first, creating a glycemic response.

Shade limits the production of sugars by the pasture. So plant trees.

The seed head and roots of the grass are the highest in NSC. So cut the grass before the development of seed heads, as it will result in less sugar per mouthful for your horse or pony.

Dead grass CAN still cause laminitis as sugar/fructans are NOT green. NSC stays in the grass until rain (or snow) leaches it out.

Hay does not lose sugar over time (i.e. old/aged hay) but does lose vitamin A.