Module 4: Laminitis

Laminitis is a painful and potentially devastating condition. Prevention is certainly better than cure and although diet is not the only risk factor, it is one we can influence – unlike genetics! Brushing up on your knowledge of the latest feed and management advice will help you to advise your customers how to reduce their horse’ s risk. Being able to spot the signs of an attack early will help to maximise the horse’s chance of recovery if they do develop laminitis.

This training section is full of tips and information but for specific advice, please advise your customer to contact the Care-Line, especially if the customer’s horse/ pony is severely insulin dysregulated.

HAL is now considered the most common form of laminitis and includes cases of laminitis associated with Pituitary Pars Intermedia Dysfunction (PPID) or Equine Metabolic Syndrome (EMS). 

The exact sequence of events or ‘mechanism’ that leads to the development of laminitis remains elusive. HAL may be triggered by the horse/ pony eating enough non-structural carbohydrate (NSC) or ‘starch and sugar’ from feed or forage to cause a sufficiently high or persistent increase in the amount of insulin circulating in the blood, although exactly how this causes laminitis is still not clear.

Laminitis is thought to affect up 1 in 10 of the equine population. Although any horse or pony can develop laminitis, a number of risk factors have been identified including:

• High intakes of non-structural carbohydrate (NSC) or ‘starch and sugar’.
• Insulin dysregulation (ID).
• Genetics e.g., certain native breeds.
• Pituitary Pars Intermedia Dysfunction (PPID) or ‘Cushing’s syndrome’, especially in the presence of ID.
• A history of laminitis.
• A recent change in grazing or move to ‘high quality grazing’ - regardless of the season!
• Recent weight gain and obesity, particularly in horses and ponies with a body condition score (BCS) of 7 or above on the 1-9 scale (although lean horses and ponies can be at risk too).
• A low concentration of adiponectin in the blood. Adiponectin is a hormone produced by fat cells thought to help improve insulin sensitivity.

Ideally horses and ponies should be provided with as much suitable forage (or if necessary, a forage replacer) as they will eat, while being mindful of excess waste. If your customer is concerned about weight gain, suggest they try to find ways of reducing the calorie density of their forage e.g., feeding soaked hay or gradually replacing part of the forage ration with clean straw, rather than restricting the amount of forage fed where possible. However, free access to forage may not be appropriate for good doers in which case, some level of restriction will be needed. 

For most overweight horses and ponies, total forage intake should not be restricted to less than 1.5% of current bodyweight on a dry matter basis. For a 500kg horse without grazing, this is equivalent to approximately 9kg of hay if it is to be fed dry or 11kg if it will be soaked before feeding on an ‘as fed’ basis (the amount of hay that needs to be weighed out). The difference in feeding rates often causes confusion, for specific advice, call the Care-Line.

Tips for managing grass intake: 

• Restrict or remove grazing – horses and ponies at very high risk may need to be removed from grazing completely, especially at certain times of year such as during spring and autumn.
• Beware of binge eating! Turning out for short periods may be counterproductive. Ponies can consume almost 1% of their bodyweight (dry matter) in only 3 hours. This may equate to two-thirds of the total daily forage allowance for those on a weight loss diet!
• Consider using a grazing muzzle. Grazing muzzles have been shown to reduce grass intake by approximately 80% in ponies turned out for three hours, regardless of the season. However, some horses and ponies may simply eat more once their muzzle has been removed to compensate, so consider stabling or non-grass turn out for remainder of the day. Grazing muzzles should always be introduced gradually, be well fitted and should not be left on 24/7.
• If available, consider non-grass turnout for those at very high risk or at certain times of year. This can be a useful way of encouraging voluntary exercise and providing time for socialisation.
• Try turning out at times and in places where WSC levels may be lower, for example overnight, early in the morning and in shady areas or on cloudy days.
• Avoid turning out on pasture exposed to bright sunlight in conjunction with cold temperatures e.g., sunny frosty mornings.
• Avoid turning out on recently cut hay stubble.
• Where possible, avoid pastures with grasses likely to a have high WSC level content e.g., predominantly rye grass pastures.

• Consider replacing 30-50% of the total forage ration with straw for good doers without dental issues.
• Any straw fed should be of good hygienic quality and introduced gradually

If your customer suspects their horse or pony has laminitis, suggest they stable them on a deep bed that goes all the way to the door and call the vet immediately. Box rest is essential for preventing further damage to the laminae and the vet will often prescribe pain relief. Initial diagnosis is often made based on clinical signs but in some cases X-rays, blood tests or other clinical tests may be needed to provide more information about the severity or potential cause of laminitis.

You have now completed Module 4: Laminitis and should have a basic understanding of the key risk factors, early warning signs, and how to guide customers towards suitable feeds and feeding practices for horses and ponies prone to or recovering from laminitis.

To secure your AMTRA points, don’t forget to take the short quiz now. This will test your knowledge, reinforce your learning, and ensure your completion is officially recorded.

You can now move on to the next topic in Module 4: PPID