Can laminitis become a thing of the past? The answer is yes – now, it pretty much can. In recent years, we have come so far in understanding the aetiology and pathophysiology of the condition, although there’s still plenty to uncover.
Aside from the causes less commonly encountered in first-opinion practice, such as endotoxaemia, most laminitis cases are associated with hyperinsulinaemia. How insulin causes laminitis is not yet fully understood, but the correlation is undeniable.
Excessive insulin levels, or inappropriate insulin response, is characteristic of pars pituitary intermedia dysfunction (PPID). However, where this has been ruled out, the majority of laminitis cases are, in fact, caused by insulin dysregulation as a result of increased adiposity.
We know that being fed too much and doing too little is a primary cause of obesity in all species, but there are many other factors at play which require consideration. Prevention is always better than cure, and in this case, will save us from the difficulty of trying to effect weight loss, which, as anyone who has tried knows, is a huge challenge to embark on.
We know that being fed too much and doing too little is a primary cause of obesity in all species, but there are many other factors at play which require consideration
How to avoid obesity-related laminitis
To avoid obesity-related laminitis, rectify it where it exists and avoid the disastrous consequences that accompany it, we need to consider the following at four distinct stages.
Stage 1: At the point of breeding
It is highly likely that a propensity to gain weight in horses is influenced by genetic factors, as has been discovered in other species, such as dogs, mice and humans. While the identification of specific genes may allow for screening, it may not be necessary to wait for that discovery in horses. If we employ the age-old tactic of selective breeding, this slow but essential burn could help avoid the propagation of genes that predispose horses to weight gain.
Addressing the obesogenic environment where breeding and youngstock are kept may provide another opportunity to influence phenotype. We know epigenetics plays a huge part in how individuals develop and what characteristics they display, so paying attention to how mares are managed and youngstock are raised may better equip those individuals for the future.
Mimicking the natural fluctuation of weight which accompanies the seasons may be more protective than we realise. This is because it relates to how well horses respond to weight gain and weight loss, and in terms of insulin regulation.
Stage 2: At the point of purchase/sale
Purchasers (and sellers) could be more conscious of the suitability of certain breeds and types of equids and how this relates to their intended purpose and management. Some typically “steady” breeds, reputedly better suited to more novice riders, are, in fact, some of the hardest types to keep in terms of weight management. The impact of this on horse welfare and owner experience should not be underestimated.
Some typically ‘steady’ breeds, reputedly better suited to more novice riders, are, in fact, some of the hardest types to keep in terms of weight management
If horses are overweight at the point of sale, it should be noted and discussed at the time of purchase and/or vetting. The influence weight has on the suitability of the horse for the purchaser is undeniably important, and the repercussions could be massive for all involved.
Equine insurance providers are considering the increased risk overweight horses pose with respect to laminitis risk, musculoskeletal disease, and so on. It would not be unreasonable for them to consider charging higher premiums for those individuals purely based on the mathematics involved.
As a result of the above, we could eventually see obesity increasingly influence the value of a horse or pony, with those overweight deemed of lower value than they would be at a healthy weight.
Stage 3: Monitoring and management
When it comes to assessing laminitis risk, there are now ways to quantify it in order to respond appropriately. Post-prandial insulin levels are reliable indicators of whether a horse has a normal insulin response to its given diet. This can be reliably used to determine how at risk of developing laminitis an individual is, making it a game-changer in equine practice.
It is important to consider the individual’s history, such as previous episodes of laminitis, concurrent disease, foot conformation, breed/type, etc. Once laminitic risk is evaluated, the appropriate management protocols can be tailored to suit the horse and the owner, taking into account the changes that are feasible in terms of environment and management system.
As fat tissue reduces in size and/or insulin response improves, it is possible to make appropriate adjustments with the aim of achieving a long-term diet, exercise and management system that maintains a healthy weight range and normal insulin response.
Stage 4: Acute treatment options
While the treatment of acute laminitis has remained largely unchanged over the years (being restricted to pain relief, anti-inflammatories, corrective farriery and cold therapy), medication is now available to counter the excessive blood insulin levels which lead to laminitis.
SGL-2 inhibitors have revolutionised the management of horses with insulin dysregulation as they provide protection from laminitis while management changes are effected and fat loss is instigated.
By keeping the breakover point further ‘back’ with a shorter toe, you can minimise the strain placed on the lamina tissues regardless of whether they are under metabolic insult at the time
Alongside these medications, there is a better understanding of the factors which limit recovery from laminitis, such as foot conformation. Leverage on the lamina tissues, caused by excessive toe length, can hinder recovery and even exacerbate laminitis. By keeping the breakover point further “back” with a shorter toe, you can minimise the strain placed on the lamina tissues regardless of whether they are under metabolic insult at the time.
Final thoughts
With so much progress being made in the field of laminitis, it is all the more surprising that it is still so frequently encountered in the field. However, as we know from humans, anything inextricably linked to obesity is never going to be easily overcome.
Obesity management remains a lethal nemesis we must face in modern society, but one we must do our utmost to battle tirelessly with all the knowledge we can yield and tools we can muster. Nature provides enough enemies for us – we have no need to create our own.
