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Laminitis

By November 19, 2018 No Comments

Laminitis doesn’t need much introduction. If you’ve been fortunate enough, however, never to have had a horse or pony suffer with it, the key point you need to know is that it is a whole-body (systemic) disease that causes damage to the horse’s foot, leading to pain, lameness and potentially, euthanasia.  Laminitis is classed as a syndrome rather than single disease because there are a range of different causes.

Some facts about laminitis:

  • In 350BC Aristotle used the term ‘barley disease’ to describe grain-overload laminitis, confirming a historical link between diet and laminitis
  • An acute overload of starch can trigger laminitis
  • Chronically increased insulin e.g. from insulin resistance, can trigger laminitis
  • Some horses and ponies have a genetic susceptibility to pasture-associated laminitis (likely to be due insulin-resistance associated chronic high intakes of sugar and fructan, in UK pasture kept animals)
  • ‘Endocrinopathic laminitis’ is used to describe the disease when its associated with obesity, insulin resistance or PPID (Cushing’s syndrome)
  • PPID increases the risk of laminitis, with up to 80% of PPID horses affected
  • Laminitis is not well understood and this includes its treatment, management and prevention

Early diagnosis is important

Once a horse or pony has suffered a bout of laminitis, they are likely to suffer again, so prevention is better than cure. Early intervention increases the likelihood of a good outcome so owners should learn to spot the early signs. Damage occurs long before the horse goes obviously lame. Early warning signs include:

  • A bounding digital pulse or hooves that stay hot (they usually fluctuate)
  • Slight increase in resting heart rate
  • Shifting from foot to foot, or being ‘glued’ to the ground
  • A shortened stride
  • Chronic signs in the hooves – distorted hoof shape with rings, faster heel than toe growth, stretched laminae
  • Obesity, PPID or increased insulin levels (all are associated with an increased risk)
  • Lose excess body fat – a healthy condition means you should be able to feel the ribs and there is no hard fatty crest
  • Speak to your veterinarian regarding PPID
  • Restrict grass and choose hay very carefully (less than 10% WSC)
  • Ensure the diet is balanced with an appropriate source of vitamins and minerals, and ensure enough good quality protein

Early Action Plan

Always call your veterinarian if you suspect laminitis. Take their advice and speak to them about testing for PPID. Remove the affected horse or pony from pasture (if relevant) and give them a soft bed. Reduce feed intake by 20-25% for a few days, by stopping any starchy or sugary hard feed and reducing hay intake (but never any lower than 1% bodyweight of dry matter (DM) intake daily e.g. 5kg DM for a 500 kg horse). Spread hay feeding throughout 24 hours, feeding the largest portion as late as possible in the evening. You can gradually increase forage intake up once you have found suitable forage and ideally aim for an absolute minimum of 1.5 % of bodyweight intake for horses who need to lose weight. Never starve a laminitic because you could induce the potentially fatal condition hyperlipaemia.

Feeding and Nutrition

If you want to reduce the risk of any horse or pony, then avoid obesity and monitor them for the early signs as outlined earlier. Unfortunately there isn’t much proven evidence for how best to feed a laminitis case, either acute or chronic. The best we can do is to ensure a healthy bodyweight, keep dietary WSC (water soluble carbohydrates, sugar and fructan) and starch to a minimum, and balance the forage correctly with vitamins and minerals.

To manage an affected horse or pony, the four most important points are:

Ensure a healthy bodyweight

Obesity increases the risk of laminitis possibly via hormonal or inflammatory influences, and puts excess pressure on weakened feet in chronic cases. You should be able to feel the ribs and the horse or pony should have a soft, flexible crest.

Test for PPID

The laminitis associated with PPID may be impossible to control with the diet, so it is important that this condition is diagnosed and treated with medication if it is present.

Restrict grass and choose hay carefully

Grass will need to be restricted to avoid an excess intake of WSC. Be more concerned with the amount of grass the horse or pony has access to, rather than the type/length/lushness. Overgrazed grass may not be ideal but it’s often the only way to restrict intake enough. Consider grazing muzzles, strip grazing and track systems.

It’s imperative that hay is chosen carefully. Never assume that a meadow hay – even if organic or old – is safe to feed to a laminitic. Always have it analysed and if in any doubt, soak for 10-12 hours to reduce the WSC and energy. Timothy hay is generally lower in WSC and energy compared to meadow hay. Haylage is usually lower in WSC than hay, but often higher in energy. You must consider both energy (calorie) and WSC (sugar and fructan) content of the forage.

Sugar is well digested by horses and does not cause gut disturbance like starch or fructan can. It is associated with laminitis via insulin resistance, not a direct effect but it should still be limited.

Balance the diet

All horses and ponies need added vitamins and minerals (micronutrients) in the form of a feed or supplement, to make up for deficiencies in forage. Laminitics rely on adequate micronutrients for healing and are likely to have lower intakes than normal due to their restricted grass and forage intakes, and often, soaked forage. Pay particular attention to the intake of vitamin E (a potent antioxidant), zinc and copper (two essential microminerals that are key for hoof health) because all three are missing in hay.

Consider topping up protein quality by feeding extra essential amino acids lysine, methionine and threonine.

Other dietary support

In most cases, a digestive-supporting supplement such as probiotic is worthwhile, especially in acute cases and starch overload cases. For chronic cases with elevated insulin levels due to insulin resistance, herbs and spices including cinnamon, fenugreek and psyllium husks are recommended, along with a good intake of magnesium. The blood-vessel and circulatory system-supporting herb hawthorn has long been recommended for laminitics, who will often pick at it in hedges themselves, if given the opportunity.

Exercise

Give as much exercise as possible depending on the strength and integrity of the feet, but always take your veterinarian’s and farrier or hoofcare professional’s advice on the amount of exercise. From a nutrition point of view, exercise is good because it helps weight loss in overweight animals, and it helps balance the hormone disturbances that are associated with a risk of laminitis (including insulin resistance).

Conclusion

Laminitis is a dreadful, debilitating disease, which should always be taken seriously. There are great debates about what exactly causes it, how it happens and how to treat and manage it, and this reflects how little we truly understand about it. To date, we know that the main factors in its prevention and management include maintaining a healthy weight, avoiding excess intake of pasture grass, starchy feeds and high-WSC forage, and ensuring a well-balanced diet. 

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