Dee Pollard from the Animal Health Trust provides 10 facts about laminitis that every horse owner needs to know.
"As horse owners, we all dread hearing the word “laminitis”. It occurs when the interlocking lamellae, which suspend the bones of the foot within the horse’s hoof, undergo degenerative changes and are ‘weakened’. Debilitating foot pain results as the lamellar changes progress, and it is very difficult to predict what the prognosis for the animal will be. In severe cases, lamellar damage can lead to the loss of a horse’s career - or even more tragically, their life.
Anatomy of the healthy horse foot showing the internal structures (Image courtesy of Prof. Chris Pollitt).
The complex nature of laminitis, and the fact that it is triggered by the interaction of several factors, makes it difficult to pin-point the exact cause of the disease. However, it is known that several disease processes are associated with its development. These include systemic disease/infections, inflammation, blood circulatory changes, hormonal imbalances and/or mechanical trauma or overloading.
In the past 20 years or so it has become increasingly evident that hormonal imbalances due to endocrine disorders are amongst the major causes of laminitis we see in our general equine population. These include equine metabolic syndrome (EMS) and pituitary pars intermedia dysfunction (PPID).
EMS is often characterised by obesity, insulin resistance and increased susceptibility to laminitis. PPID (also known as Equine Cushing’s Disease) is associated with ageing-related progressive changes in the pituitary gland, which affects the normal secretion and inhibition of hormones, leading to changes in metabolism and increased susceptibility to laminitis. A possible link between EMS and PPID has been proposed – suggesting that animals with some or all the EMS characteristics may be more at risk of pituitary dysfunction later in life.
Example of a foot showing the normal position of the pedal bone (parallel to the hoof wall) and pedal bone rotation in a severe laminitis case (Images courtesy of Prof. Chris Pollitt).
While some breeds and breed-types (native horse/pony breeds and good-doers/easy keepers) seem to be more susceptible there is also great variation in susceptibility between individual animals. This makes it harder to predict which animals are more at risk, especially in the absence of underlying factors such as obesity, EMS, PPID or a previous history of laminitis. This makes it important that ALL owners are aware of the disease.
Becoming familiar with your horse or pony’s normal temperament, gait, hoof temperature and digital pulse will help to alert you to any abnormal physical or behavioural changes.
A number of characteristic clinical signs of pain and lameness are associated with the disease. Although not every case will be the same, learning to recognise what to look out for will allow earlier detection of the disease. The most common clinical signs were found to be raised digital pulses, difficulty in turning and a short, stilted gait in walk. To find out more click here.
Laminitis begins to develop some time before the horse starts showing clinical signs. By the time that the clinical signs become obvious, the changes within the foot may already have progressed substantially. It is difficult to know exactly when the disease starts developing and what the prognosis will be.
Laminitis is not a disease that can be cured. Once an animal has had laminitis, there is a much greater risk of it happening again. These animals then require careful ongoing management. If we can identify the factors which make laminitis more likely to develop, we can put in place strategies to reduce the risk.
Once considered to be a mainly spring-time disease, laminitis has been found to occur year-round with regional and seasonal differences. A recent study has shown that the risk of laminitis within that study population was greatest in summer and winter as opposed to spring. This shows that owners should remain vigilant throughout the year.
Although most commonly reported to occur in the front feet, laminitis can occur in all four feet, the hind feet or in one foot only. However, the front feet are usually most severely affected as they bear a larger proportion of the animal’s overall body weight.
Treatment and management of the laminitic animal is very case-specific and should be a collaborative effort between owner, vet and farrier/trimmer.
Recognise clinical signs and characteristics associated with PPID and EMS. If you suspect either of these disorders, discuss available testing with your vet. Medication and changes in management can help to control these disorders and thereby reduce the risk of laminitis.
Depending on how the animal responds to treatment efforts and rehabilitation, laminitis does not always signal the end of a horse’s athletic career. Identifying the likely causes of the initial episode, along with careful management and ongoing vigilance, are required to prevent recurrent episodes.
Laminitis can affect any horse or pony (Image on left courtesy of World Horse Welfare; Image on right courtesy of Prof. Chris Pollitt)
Every horse and pony has the potential to develop laminitis, however, some are more at risk than others. That is why every owner should be aware of the disease, including its underlying causes, and correctly view laminitis as a medical emergency requiring prompt attention. Because laminitis can lead to permanent and often devastating anatomical changes within the foot, which leave the horse more susceptible to future laminitic episodes, preventing the disease from developing in the first place should be our goal.
Research has come a long way to understanding how and why laminitis occurs, but there are still large knowledge gaps that prevent us from linking different processes together and determining exactly how they fit into the final picture. We still don’t have enough understanding of the proportion of horses and ponies that are affected by single or multiple episodes, nor is there enough evidence-based knowledge on how best to prevent the disease.
The Animal Health Trust, in collaboration with the Royal Veterinary College and with funding from World Horse Welfare, is undertaking a nationwide web-based study which will strive to answer these questions. The CARE (Creating Awareness and Reporting Evidence) about laminitis study aims to estimate the frequency of owner-reported laminitis in Britain, further investigate factors which increase or decrease the risk of an animal developing laminitis and provide owners with evidence-based guidelines that will reduce the impact of laminitis nationwide.
The project has already successfully recruited over 700 horses and ponies, but needs many more. Although this is a study about laminitis, it is vital that information is collected from both those animals who previously have had laminitis and those that have not. Not only will this provide an estimate of the proportion of horses and ponies that have laminitis vs. those that don't, it will also reveal how many new cases of laminitis occur during the study period. Additionally, following both non-laminitic and laminitic animals will allow us to notice if these groups are exposed to different factors which may result in the disease developing, or not developing. So anyone that owns a horse/pony is able to take part, irrespective of their animal's age, breed, use and previous or current health status.