Despite the fact that research has improved our understanding of the causes of laminitis, it doesn’t seem to have resulted in a reduction in the number of cases. Why is this? Well it may have something to do with the increase in numbers of horses and ponies that are overweight or obese.
Despite the fact that most owners are aware that if their horse or pony is overweight, they are at increased risk of laminitis, many find it very difficult to diet them effectively. There are many possible reasons for this but, just as with people, it is often because they simply don’t realise where the calories in the diet are coming from. We’ll count some calories in a typical ration in a bit but first it is worth understanding a little more about the link between obesity and laminitis in horses.
Equine Metabolic Syndrome is a name used to describe a range of symptoms that include insulin dysregulation, obesity and recurrent laminitis. Research in humans in the 1990s demonstrated that adipose (fat) tissue isn’t just an inert store; it can actually develop the ability to secrete hormones. Hormones are chemical messengers in the body, and it is known that adipokines (hormones produced by the adipose tissue) can affect immune function, inflammation, tumour development and glucose regulation.
Keeping blood glucose levels within normal ranges involves a number of hormones, one of which is insulin. If the function of insulin is compromised, then it is referred to as insulin resistance or dysregulation. As insulin facilitates the removal of glucose from the blood, insulin resistance can result in blood sugar levels remaining elevated despite more and more insulin being produced. It is thought that over-exposure to insulin and glucose can damage the cells lining the blood vessels (endothelial cells). As these are responsible for the constriction and dilation of blood vessels the link between insulin resistance and laminitis becomes apparent.
So, what can you do?
If your horse is overweight, then you need to embark on a weight loss plan. The main source of energy in most horse’s diets is grass – eight hours grazing time on average spring pasture will supply enough energy for a 500kg horse and so if you haven’t already limited turnout time then it is highly likely that you will need to There are various ways in which you can limit access to grass including stabling, limiting the area available and using a grazing muzzle.
How effective are grazing muzzles?
There have been few studies investigating how effective grazing muzzles are but the reduction in intake seen is between 75 and 85% which would have a significant impact on the amount of energy consumed. The added benefit is that the horse can still be turned out which is better for their respiratory system, allows them to interact with other horses and move around more which will use more energy than if they are stood in a stable.
It is also important not to be tempted to treat the overweight horse with a sprinkling of cubes or mix in their feed. You may be surprised to learn that ½ a scoop of mix provides enough energy to support 20 minutes schooling and if cubes are used this increases to 50 minutes schooling as they are heavier and so half a scoop provides more.
Benefits of Exercise
Although it can often seem that however much work you do with your horse they don’t seem to lose weight, it is important to keep doing it. It may be that the exercise you are doing is being counteracted by not reducing calorie intake sufficiently so this has to be addressed. It is also important to consider that even if the horse isn’t losing weight, exercise may help to maintain sensitivity to insulin as has been found to be the case in humans. Therefore, even if the horse isn’t losing weight, exercise may help to avoid insulin resistance and laminitis.