Unfortunately, one of the biggest risk factors for laminitis and founder in horses is domestication. In the wild, horses will often cover very long distances looking for food and water and their digestive systems have evolved to be very efficient in obtaining energy and nutrients from sparse low-calorie fodder.
With domestication, however, the horse is generally locked up in small, lush paddocks. They no longer have to walk long distances to find food and water and they have access to high calorie and sugary improved pastures 24 hours a day.
Lack of exercise and an inappropriately high carbohydrate diet are the two biggest causes of laminitis and founder in horses.
If your horse has unrestricted access to grass and doesn’t get much in the way of exercise, then he or she may be at risk of Laminitis.
Many breeds have a genetic predisposition to insulin resistance making them much more prone to laminitis. The native breeds seem to be at high risk as well as breeds such as Morgans, Arabs, Spanish horses and Miniature Ponies.
Obesity has been linked to insulin resistance and is generally considered the most common cause of laminitis and founder in horses. The hormonal and metabolic consequences of obesity turn your fat horse into a ticking time bomb! If you can get familiar with the body condition scoring system in the next section, it will help you assess your horse’s level of risk.
A sedentary horse is often a fat horse. Exercise is one of the most effective ways to guard against insulin resistance. It also will help to prevent your horse from becoming obese.
Cushing’s disease usually shows up in horses approaching their late teens and becomes very high risk for horses in their 20’s.
Springtime is when most horses are at the highest risk of laminitis. This is because the spring flush of grass can be very high in sugar and starch which can trigger IR type laminitis. Autumn is also risky for horses with Cushing’s as there is a seasonal rise in the hormone that drives the symptoms of Cushing’s at this time of year. Again there is often an Autumn flush of grass growth ahead of winter.
Acute sickness or surgery can lead to Systemic Inflammatory Disease or SID.
Serious systemic disease with septic or toxic focus can cause laminitis. The horse will show signs of systemic (whole system) illness and have a raised temperature and often have diarrhoea. Causes might include post-colic surgery, colitis, peritonitis, poisoning or retained placenta in a mare.
Carbohydrate overload is also included under the category of SID. Acute laminitis can be induced very quickly if a horse’s hindgut is exposed to a large volume of carbohydrates. This is commonly seen when a horse breaks into the feed room – for example – and gorges itself on grain.
Corticosteroid – known as steroids – can trigger or worsen laminitis in some horses, especially those already at risk of metabolic or endocrinological laminitis. Examples of corticosteroids include cortisone, prednisone, and methylprednisolone.
Carbohydrate overload can happen if a horse suddenly gorges on grain; for example, the pony who breaks into the feed room and eats half a bag of oats! This can cause an acute laminitic attack.
Stress is thought to be a contributing factor in laminitis and may worsen IR. Unfortunately, the already laminitic horse is at risk of being highly stressed. Changes in herd dynamics and management such as restricting grazing and turn out without herd mates will lead to stress.
The other major cause of stress for laminitic horses is feed restriction. Many people starve their horses as a first response to the initial laminitis diagnosis. This can be very damaging.
Do not starve a laminitic horse! Starvation can cause a condition called hyperlipaemia and can worsen IR. The horse must be provided with a slow and constant trickle of food, this is best achieved by using a slow feeder hay net or similar, see the section on Management Tools.