In the previous issue of Equestrian Life, we discussed the nature of the devastating disease laminitis and different approaches to its treatment. Here, in Part II, we look at managing the disease and the chances of recovery, first from a vet’s viewpoint, and second, from the farrier’s.

 

 

David T. Wood BVSc, MRCVS, is a veterinary surgeon with 35 years’ equine experience gained in several countries. For the past 20 years he has pursued a special interest in equine nutrition and currently acts as veterinary and technical advisor to Horsepower.

 

In the first part of this review of laminitis, some of the causes and mechanisms of the disease were covered, from which it is clear nutrition plays a key role in events leading up to an attack. Naturally then, nutrition also is an important consideration in the treatment and management of the condition and the outcome for your horse.

 

 

Due to the severity of the condition and the risk of permanent damage to the foot, laminitis is always a matter for veterinary first aid, which should be sought immediately. The most useful thing a horse owner can do in the early stages is to cool the feet of the horse until professional help arrives. Do this with a cold hose or buckets of ice water intermittently for 10 minutes at a time with five-minute breaks in between, until professional. Pain medication should not be given as it may mask the severity of the condition on clinical examination by the vet. Suspected cases should be removed from pasture into a well-bedded stable where they can lie down to relieve the pain in their feet. Shoes should be left on until veterinary examination. 

 

Veterinary treatment in the acute phase will revolve around the following:

 

 

The veterinarian may arrange radiographs of the feet to help determine the degree of rotation of the pedal (coffin) bone if that is suspected. They may also advise on corrective trimming of the feet and shoeing with a specialised shoe such as the “Heart Bar shoe” or “W” shoe, or the use of rubberised boots and sole padding which will require the services of a competent farrier as soon as practicable. Meanwhile box rest, preferably in a box with a good soft bed, is appropriate – these horses often need to lie down for sustained periods to alleviate the pain in their feet. Continued application of cold during the first couple of days may also help provide relief.

 

Feeding at this stage should best be forage feeds like hay and chaff only for the first few days, with the possible addition of a bran mash early on if the vet agrees. Access to lush pastures should be avoided altogether as the fructan content is unknown and could make matters worse. Your vet is the best placed person to advise on what to do and what to expect as well as providing some estimate of the prognosis, corrective shoeing and other treatment options. For horses that survive the initial attack, the following general advice may be helpful.

 

 

A horse which has had laminitis once is four times more likely to suffer a repeat episode than one which has never had the disease, and special care in their feeding is warranted. Some fall-off in condition following the initial attack is almost inevitable, and in fat ponies especially, not always a bad thing. For that particular group though, sudden weight loss can be linked to a condition called “hyperlipaemia” where rapid mobilisation of fat stores can lead to excessively high fat levels in the blood with serious consequences, so their weight needs to be carefully managed.

 

The basic premise for feeding these horses is to avoid high-energy, high-soluble carbohydrate diets and aim to derive as much of their energy requirement as feasible from fibre and possibly fats. High-fibre diets have two advantages for the prevention of laminitis:

 

 

For the same reason, sugars such a molasses should be avoided and the practice of soaking hay in water for a while to remove soluble sugars makes sense. Conversely, sugar beet pulp, now widely available in Australia from imports, is actually very low in sugars which have been removed during processing, and is a good source of highly digestible soluble fibre and very suitable for laminitis cases. Some sugar beet products have traces of molasses added for palatability but the amount is small and unlikely to cause trouble. High-energy feeds including grains such as corn, oats and barley should be treated with extreme caution and fed sparingly, if at all.

 

 

 

Note. Energy values are expressed as megajoules per kg on a dry matter (DM) basis.

 

Lucerne hay or chaff is a good source of quality protein and is suitable as part of the forage ration. The use of “hoof supplements” containing biotin often with trace elements such as zinc and manganese does help improve the quality of hoof horn and rate of growth and is also a good idea.

 

Oil is a useful addition to the diet for these laminitic horses where some additional energy is needed following the recovery phase. Like fibre, it uses a different energy pathway from starch and sugars and provides a safer energy-rich alternative. When using oil simply as an energy source, buy the cheapest – they all have similar energy content, and the balance of fatty acids like omega 3 and omega 6 is immaterial for this purpose.

 

 

 

Because of the potential for high fructan levels in grasses at certain times, pasture can be problematic for these horses.  Fructan is a sugar storage compound formed by plants to store the energy produced by photosynthesis. The concentration in the plant tends to fall during darkness and rise over the course of the day reaching a peak in early evening. Grazing for these at-risk horses should logically therefore be safer during the first three hours after dawn. Fructan levels also tend to be higher in spring and autumn and lower in winter and mid-summer pastures, though the actual pasture concentration of these soluble carbohydrates is unpredictable and unfortunately you can’t tell just by looking. Despite this, prohibiting pasture access is probably unjustified in all but the most sensitive cases and the benefits in terms of exercise and a natural life probably outweigh the risk. Limited access or the use of a grazing muzzle is a reasonable compromise with minimal time spent on lush pastures in the afternoons especially.

 

 

Some recently published studies from the UK have shed light on the risk factors for laminitis with some expected, and some surprising, results:

 

 

The take-home message is that hormone-related laminitis is probably the most common form, small fat ponies are at the highest risk and laminitis is an all-year-round disease. Keeping your horse at the correct body weight for its size is critical in prevention.

 

 

The time taken for a horse to recover from laminitis, and the degree of function regained, varies considerably with the severity of the first and perhaps subsequent attacks. The main prognostic tool used by vets to predict the likely outcome is X-ray examination of the feet, especially with respect to rotation and other damage to the pedal bone. In the mildest cases where no rotation has occurred and pain subsides fairly rapidly within a week or two, the outlook is cautiously positive. Many of these horses will return to full normal function, though it may take two to six months to get back to their previous form.

 

Once the pedal bone has rotated, even slightly, pain will persist for a longer time and corrective shoeing and trimming will be needed for many months or years. The prognosis for a full return to normality is guarded and ongoing assessment is needed as treatment progresses.

 

For those most severe cases where the pedal bone has detached extensively from the hoof wall and rotated down onto, or even through the sole of the foot, the outlook is grim. A proportion may be able to become paddock sound for use as broodmares for example, but almost none will return to athletic use or even be suited for light riding.

 

In these worst cases, sometimes called “sinkers”, where the pedal bone protrudes through the sole the horse is probably crippled for life. Euthanasia is often the only option and better it be done soon rather than delayed, which prolongs the suffering. The scenario to be avoided is weeks or months of fruitless treatment ultimately ending in euthanasia.  Treatment of severe cases is debilitating for the horse and owner alike and frustrating for the vets and farriers involved when months of effort fail to produce an acceptable outcome.

 

The best course is avoidance. An awareness of the risk factors such as obesity, recent weight gain, hormonal diseases and high energy feed is the essential tool in management of this potentially devastating condition where the old adage of “an ounce of prevention is worth a pound of cure” certainly holds good.

 

Part III of this story can be viewed here: http://www.equestrianlife.com.au/articles/There-is-life-after-laminitis

 

 

 

A cohort study of equine laminitis in Great Britain 2009–2011: Estimation of disease frequency and description of clinical signs in 577 cases. C.E. Wylie, S.N. Collins, K.L.P. Verheyen, J.R. Newton. Equine Veterinary Journal, Volume 45, Issue 6, pages 681–687, November 2013.

 

A review of recent advances and current hypotheses on the pathogenesis of acute laminitis.  L.M. Katz, S.R. Bailey. Equine Veterinary Journal, Volume 44, Issue 6, pages 752–761, November 2012.

 

Pasture Nonstructural Carbohydrates and Equine Laminitis. Annette C. Longland*, Bridgett M. Byrd†

J. Nutr. July 2006 vol. 136 no. 7 2099S-2102S.

 

Risk factors for equine laminitis: A case-control study conducted in veterinary-registered horses and ponies in Great Britain between 2009 and 2011. Wylie C.E., Collins S.N., Verheyen K.L., Newton J.R. Vet J. 2013 Oct; 198 (1):57-69. doi: 10.1016/j.tvjl.2013.08.028. Epub 2013 Sep 4.

 

Explaining Laminitis and its Prevention. Robert A. Eustace BVSc, Cert EO, Cert EP, FRCVS.  The Laminitis Clinic, Chippenham, Wilts SN15 4JA, England.

Pasture Paranoia; Laminitis Prevention. Fran Jurga. The Horse, Feb 1,1999. 

 

Making Sense of Laminitis. Michelle N. Anderson. The Horse, Feb 1, 2013.

 

Nutrient requirements of Horses 6th Ed. 2001, National Research Council of the National Academies.