Contrary to the popular belief, laminitis occurs all year-round, not just in the spring. It is an emergency that needs prompt action whenever it is suspected, so find out how to recognise it and what to do if your horse is showing signs
Laminitis in horses is an inflammatory condition of the laminae within the feet – the tissues that attach the pedal bone to the hoof wall inside the hoof capsule. Horses and even more so ponies, will develop laminitis for many reasons, rather like people have headaches.
Laminitis occurs when the sensitive laminae within each foot become inflamed, but they are unable to swell since they are restricted by the solid external structure of the hoof. This leads to the horse feeling extreme pain and adopting the classic leaning back on the heels posture in an attempt to relieve the pressure from the front of the hoof. In the most severe cases the horses will lie down as their feet are too painful to bear weight.
An acute new episode or flare up of laminitis is a veterinary emergency and an equine vet should be called to assess any horse with suspected laminitis as a matter of urgency. Some horses and ponies have long standing chronic laminitis, which may not be an immediate emergency, but still needs proper care and attention. According to the RVC1 more than 7% of equine deaths are linked to laminitis, with many cases being put down on welfare grounds.
Laminitis can develop very rapidly. It can result in the pedal bone sinking or rotating within the hoof and in extreme cases the pedal bone can drop so far that it penetrates through the sole. If the pedal bone completely detaches from the hoof wall then the horse has ‘foundered’ and euthanasia may be the only option.
Laminitis: Signs | Diagnosis | Causes | Treatment | Prevention
Signs of laminitis
Lameness is typically seen in all four legs, although the forelegs may appear more badly affected.
- The earliest sign may be a shorter than normal stride
- The horse being reluctant to walk on hard or stony going
- The horse may appear more lame on hard ground and turns
- It may shift its weight between feet when resting
- Increased digital pulse at the back of the pastern/fetlock
- The hooves may feel warm to the touch
- Pain with use of hoof testers, especially around the point of frog on the foot
- The horse stands leaning back onto its heels
A horse with chronic (i.e. long standing) laminitis that has suffered repeat bouts of the condition is likely to have misshapen feet with horizontal rings or lines visible on the hoof wall, which are wider at the heel than at the toe. The sole of the hoof may be flat or convex, with a wider than usual white line.
How is laminitis diagnosed by a vet?
A vet should be consulted if laminitis is suspected and will usually diagnose the condition based on the clinical signs. X-ray images are useful to confirm whether the pedal bone has sunk or rotated, which will help as a guide to prognosis and inform the farrier fitting shoes. Blood tests can be very useful to help identify if any underlying endocrine disease is responsible.
Causes of laminitis in horses
In general, ponies tend to be more susceptible than horses to laminitis. Risk factors associated with the disease include a flush of fresh grass at any time of year, grazing when the grass is under stress (such as after frost or severe overgrazing) and horses that are overweight.
Interestingly, a 2021 study2 conducted by Scotland’s Rural College in collaboration with the Waltham Petcare Science Institute found that steps taken to protect public health during the Covid-19 pandemic – including reduced exercise, turning horses away, and limiting yard visits – had the potential to compromise the welfare of overweight equines, increasing the risk of laminitis.
David Rendle, chair of the British Equine Veterinary Association’s health and medicines committee, said: “The study provides testimony that many horses spent additional time at grazing as a result of Covid health guidelines. Vets have been concerned throughout the pandemic that increased turnout during periods of good weather could tip laminitis-prone animals over the edge into clinical laminitis. The fundamental issue is the unacceptably high proportion of equines with obesity and associated metabolic disease.”
Underlying conditions that can lead to laminitis include equine Cushing’s disease (also known as pituitary pars intermedia dysfunction or PPID) and equine metabolic syndrome (EMS). The hormone insulin appears to be significant in laminitis associated with endocrine disorders.
Research3 led by Garance Christen at the Swiss Institute of Equine Medicine, University of Bern, published in 2020, found that horses aged over 25 may suffer from chronic laminitis without displaying any outward signs or suffering from contributory health conditions. Almost half of the total sample of 51 clinically sound horses from different age groups (15-32 years) showed signs of rotation on X-ray, although none of them showed signs of acute lameness or PPID. Of these, horses aged over 25 were found to be three times more likely to have pedal bone rotation than horses in the younger age category.
The study’s authors said: “We think that radiographic changes are related to early or pre-clinical PPID in this cohort of horses because this remains the best explanation for the higher incidence of laminitis in the old age group.”
Laminitis can also be caused by a retained placenta after foaling, following on from another illness, limb concussion caused by excessive work on hard ground, or overload of a limb due to a severe injury of the opposing leg. In these instances, if the primary condition is effectively treated, the laminitis risk will subside.
In diseases associated with inflammation (such as certain types of colic, diarrhoea, retained placenta and severe pneumonia), the inflammation throughout the body triggers inflammation of the laminae, although why this happens remains unclear.
In mechanical overload laminitis, such as when a fracture or infected joint causes the other leg to bear all of the horse’s weight, it’s thought the excessive and continuous weight bearing may negatively affect the blood supply to the laminae.
Cases linked to concussion can occur during the summer in susceptible animals when a heatwave bakes the ground, with ponies in active service during the school holidays, as well as show horses and racing thoroughbreds, at a higher risk.
Laminitis treatment and management
A vet should be consulted regarding any suspected case of acute laminitis as soon as possible. They may prescribe non-steroidal anti-inflammatory drugs (NSAIDs) such as phenylbutazone or flunixin and potentially other painkillers to help manage the horse’s discomfort.
Foot support and complete rest to limit movement of the pedal bone is important and will help to reduce the extreme levels of discomfort. The horse should be placed on box rest on a deep bed of shavings or other similar bedding right up to the stable door. Special supports can be attached to the horse’s hooves by your vet or farrier to give additional support.
Acepromazine (ACP) has been frequently used to increase the blood supply to the feet, but it’s beneficial effect may be more due to its sedative properties, which will encourage the horse to stand still or lie down.
In cases of laminitis associated with inflammation, the use of ice to cool the feet may be beneficial, especially in the very early stages of the disease. Research comparing seven different ways of cooling the hoof4 found immersion of the foot and at least the pastern region of the leg in ice and water achieved the lowest hoof wall surface temperature for a sustained period, along with use of a prototype perfused cuff device with a dry interface. In summary, when apply cold therapy, the cooling should cover the whole hoof as well as the lower part of the leg for the greatest effect.
Diet is very important during bouts of laminitis. Clean fresh water should always be available while the horse should be fed poor quality hay, rather than grass. The hay should be soaked for at least an hour to reduce soluble carbohydrate levels. Fibre-rich feeds such as unmollassed sugar beet and low-sugar chaffs can form part of the diet. Horses should not be starved in an attempt to shift excessive condition as doing so risks triggering hyperlipaemia, a disorder of fat metabolism.
If the laminitis is the result of an underlying condition, such as an endocrine disorder, that should be treated accordingly. Discuss this with your vet, depending on the results of blood tests. If a horse or pony has insulin regulation problems caused by EMS or PPID, or both, he will certainly be at increased risk of developing laminitis and will require careful management. By diagnosing these underlying problems the vet can guide the owner more clearly and manage the case more effectively.
How can you prevent laminitis?
While it is not only overweight ponies that get laminitis, the weight of all equines should be carefully managed to reduce the associated risk. Horses of all types need to go into the spring in lean condition (where you can easily feel and just start to see their ribs) to avoid the risk of obesity as the levels of nutrition in grazing improve. Winter is a great opportunity to achieve weight loss in overweight equines by keeping them unrugged and not increasing hard feed, until really needed. Grazing muzzles can be used all year round to help control weight gain.
All horses hooves should be attended to by a qualified farrier every four to six weeks, whether they are shod or not, to maintain correct hoof balance and health. Appropriate shoeing can make a huge difference to the chronic laminitic by supporting the structures in the foot properly. There are many options of useful shoes designed to help laminitis cases including mouldable thermoplastic shoes and clogs amongst others.
The farrier who sees the case every few weeks is also in an excellent position to guide the horse owner, who sees their animal daily and therefore may not notice changes, especially in weight.
Hoof supplements can be used to promote healthy hoof growth, while other supplements are formulated to help support healthy horses on restricted grazing.
Avoid excessive trotting/cantering on hard ground, including roads, to reduce the concussion on the horse’s limbs and feet.
In broodmares after foaling, check that the whole placenta has been expelled. If you are unsure if this is the case, contact your vet urgently.
If your horse is recovering from a severe injury to one leg, discuss with your vet the best way to provide additional support to the opposing limb.
Above all be aware that we now know that there is much more to laminitis than simply avoiding lush grass. Underlying metabolic problems, proper regular attention to the feet and good general health care are all important.
- Royal Veterinary College’s laminitis fact file
- COVID-19 impacts equine welfare: Policy implications for laminitis and obesity
- Age over 25 years, but not plasma adrenocorticotropic hormone concentration above the seasonally adjusted reference range is predictive for radiographically assessed changes of chronic laminitis in elderly horses
- A comparison of seven methods for continuous therapeutic cooling of the equine digit
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