Most people look forward to the sights and sounds of spring with great anticipation. For some horse and pony owners however, the arrival of spring also means that they must reluctantly start limiting the time their horses or ponies can spend at grass.   

Restricted access to good grazing is essential for ponies susceptible to laminitis, a disease of the hoof that can vary in severity from the merest hint of lameness to a situation described as ‘sinking’, which can be fatal. As laminitis develops the attachment of the pedal bone to the hoof wall starts to fail, and if quick action is not taken, the pedal bone may become completely detached and ‘sink’ towards, or even through, the sole.  

Recognised causes of laminitis include: -

1) Excessive intake of sugars and starch (soluble carbohydrate), for example: -

a) Eating too much good quality grass, often in spring or autumn, but possible at other times of the year.

b) Eating too much cereal, either in one feed or in successive feeds.

c) Eating too much cereal-based compound feed, especially if highly molassed.  

All these situations will result in an overload of soluble carbohydrate into the hindgut, which will cause an imbalance in the microbial population. Obese horses and ponies are more at risk. When an excess of sugars or starch overflows from the foregut into the hindgut it is digested by a minority of the bacteria present. These bacteria then multiply very rapidly, producing lactic acid as they do so. Recent research has shown that as the hindgut becomes more acidic its walls become ‘leaky’ and laminitis trigger factors (LTF’s) ‘leak out’ into the bloodstream. When the LTF’s reach the foot they cause changes that are the subject of intensive research by scientists around the world. These changes precipitate laminitis.   

2) Intake of the ‘wrong type’ of carbohydrates. Recent research has indicated that closely grazed or frosted grass is high in fructans, a type of sugar that triggers similar changes in the hindgut to a soluble carbohydrate overload. This helps to explain the cases of laminitis seen in horses and ponies kept on ‘starvation’ paddocks or turned out on apparently poor grazing in frosty weather.  

3) Traumatic laminitis is caused by repeated physical trauma to the feet during eg endurance riding or jumping on hard ground; it can also be caused by over-enthusiastic hoof trimming. I mentally cringe when I see children riding their ponies at a spanking trot on tarmac roads and long to advise them to slow down. 

4)  Toxins released by bacteria during certain illnesses e.g. following retained placenta, colic, diarrhoea, liver or respiratory disease.  

5)  Hormonal e.g. Cushing’s disease (in most cases a tumour on the pituitary gland causes an increase in the circulation of natural steroids) 

6) Certain drugs e.g. the steroid cortisone, are known to have the potential side effect of triggering a laminitic attack 

7) Stress e.g. when travelling long distances 

8) Severe lameness in one limb will cause a horse or pony to carry excessive weight on his other limbs, which may cause laminitis. As with traumatic laminitis this is a physical trigger. 

Is there a cure?

Most horses and ponies can recover from laminitis but the extent of their recovery depends on many factors including how severe the problem was when it was first spotted, and how soon treatment commences. The very mildest (sub-clinical) cases can often be nipped in the bud by changes in management, especially feeding. Clinical cases need the urgent attention of a vet and should it be necessary to remove part of the hoof wall there are many veterinary practices or equine hospitals in the UK where this apparently drastic, but routine, operation can be carried out. Acting quickly and using the combined skills of a vet, farrier and nutritionist lays the foundation for the most successful recoveries. Sadly, the outlook for ‘sinkers’ is very poor so do not delay in seeking veterinary treatment. 

What action should be taken following an attack?

In those cases where a digestive upset in the hindgut is the trigger for an attack nutritional advice should centre on re-establishing the correct bacterial population, and therefore the correct acidity, in the hindgut. This is one in which fibre-digesting bacteria predominate and bacteria which digest sugars and starch are not allowed to proliferate.  

The first action to take therefore is to remove the cause of the laminitis eg bring the pony in from grass or, if the pony was previously receiving any cereals and/or compound feed cut them out of the diet. Stable the horse or pony on a deep bed of shavings. Provide ample fresh water. Call the vet immediately and the farrier when appropriate. Do not remove shoes unless, following X-rays, your vet advises your farrier to replace them with eg heart bar shoes.  Discuss what to feed with an experienced nutritionist. It is important to minimise the levels of sugar and starch in the diet but to provide ample fibre. Never starve a laminitic as this can have fatal consequences. 

A typical initial regime for a small native pony would be to offer approximately 3kg of a mixed alfalfa/straw chop with a low-sugar coating and one small flap of late-cut hay per day. Because this regime is deficient in micronutrients it is essential to feed a broad-spectrum supplement to enable tissue repair and maintenance to take place. A fully comprehensive supplement that also includes probiotics and optimum levels of the nutrients needed to improve hoof quality is ideal. Probiotic substances include ‘true probiotics’ such as lactobacillus acidophilus, which works in the foregut and may help to reduce carbohydrate overload into the hindgut, yeasts and MOS. Yeasts create beneficial conditions for the growth of the fibre-digesting bacteria in the hindgut. MOS (mannan oligosaccharides) bind to the sugar and starch-digesting bacteria and remove them from the gut in the faeces, thus minimising the production of the lactic acid that triggers the chain of events that lead to a laminitic attack. By removing the acid-making bacteria MOS leave the beneficial, fibre-digesting, bacteria free to multiply. 

The nutritionist will slowly improve this regime to provide a more nutritious diet according to the progress of each individual case. Whenever possible the diet should remain fibre-based, taking advantage of the wide range of such products available today. These include products like unmolassed beet pulp, alfalfa in various forms and blends, and pasture nuts. The old adage of feeding little and often is particularly important. 

Keep the horse or pony on box rest until he is sound and off all painkilling drugs. Forced exercise when pain is masked by drugs will lead to further damage. 

When the horse or pony has been completely sound for a month the use of a cereal-free feed balancer, as a palatable and concentrated source of vitamins, minerals and probiotics, can be very helpful. In those cases where condition needs to be built eg for showing, it is important not to rush the weight gain and to use oil in preference to cereal-based feeds. Horses and ponies do not need to be obese to win in the show ring as the picture of a very successful pony demonstrates. 

Can laminitis be prevented?

Most cases of laminitis that are triggered by digestive upset in the hindgut can be prevented by following sensible management strategies, including adopting the type of high-fibre diets described above. The following points may help susceptible horses and ponies: - 

• Limit access to lush pastures either by limiting turnout time or by fencing off small areas with eg an electric fence. Consider using a muzzle, but only for limited periods as they can cause immense frustration, and only use them under supervision.       
• Avoid fertilised and frozen pasture. 
• Base feeding programmes on ample forage (eg late cut hay or haylage) and minimal concentrate. Using a cereal-free balancer can be very helpful.  
• Maximise the use of high-fibre feeds which produce slow-releasing energy in the hind gut eg alfalfa in various forms or blends, shredded beet pulp (discard the juice or use unmolassed), and pasture nuts. 
• Avoid feeds high in sugar eg molassed coarse mixes and straw chops. 
• Avoid feeds high in starch ie cereals or cereal-based compound feeds. If their use is essential remember that cooked cereals are less likely to trigger a laminitic attack than raw cereals, micronised barley is the best. 
• Use soya or corn oil as a ‘safer’ energy source than cereals or cereal-based compound feeds. Oil is digested in the foregut and when fed at recommended levels will not upset the hindgut. High oil diets must be supplemented with anti-oxidants, principally vitamin E and selenium. 
• Where ‘hard’ feeds are needed provide them in small amounts ie little and often. Reduce the standard recommendations so that a 15hh horse for example never receives more than 3lbs (dry weight) of ‘hard’ feed in any one feed. The standard recommendation would be not to exceed 4lbs/feed. 
• Never make rapid changes in the diet eg do not suddenly turn out onto good pasture. Introduce it gradually. Similarly, make all changes to forage or hard feed gradually, over at least four days. 
• Avoid letting horses and ponies become obese. For showing, a well-furnished look with good topline can be achieved by feeding and working to build muscle with minimal use of cereal-based feeds. 
• Monitor the digital pulse daily to give you an early indication of imminent lameness. Better methods may be on the horizon. 
• Avoid unnecessary trauma to feet eg minimise trotting on roads and do not jump working hunters or show jumpers on hard ground.  
• Bear in mind that although native ponies and ‘good-doers’ are most susceptible, all types of horses and ponies can and do get laminitis. 

The circumstances surrounding every case of laminitis are different and the speed of recovery varies. I would suggest therefore, that you consult an experienced nutritionist to help you adapt the generalizations I have given to meet the specific requirements of your horse or pony. In the majority of cases managing laminitis is all about managing the microbial population of the hindgut. I am full of admiration for the dedication shown by many owners of laminitics and feel that they have become experts in a specialised form of ‘population control’.