By Dr Erin Roddy, DVM

For decades, the general horse community has shared the belief that the best method for forced weight loss in a Laminitic horse is extreme caloric restriction. People have tried to help their Laminitic horses by putting them in the ‘Jenny Craig Paddock’ or even on a ‘Starvation Diet’. However, new scientific research is telling us that starvation is not the answer. 

In fact, the opposite extreme to starving a horse is actually the best method for controlling Laminitis, as well as insulin resistance.

Laminitic horses should be given free access to SAFE long stem forage. 

Yes, laminitic horses should be given free choice access to very long mature grass or long stem hay, with a NSC (Non-structural carbohydrate) level of less than 10%, with no restriction.By this we mean we recommend making more long stem forage available than the horse is capable of consuming.  Ideally you will test your forage NSC level so you know it is safe for your laminitic horse or pony.  Unfortunately even hay that appears safe can sometimes have a higher than desirable NSC value so if we test it first we know if it is safe to feed as it is, needs to be soaked or isn’t suitable at all.

This theory about how to deal with laminitis certainly goes against what most horse owners have been taught, and the change in information can be extremely confusing and seem illogical - but it is absolutely true.

Long stem forage, and a diet low in sugar and starch is the key

To clarify; free choice refers to allowing the horse unlimited access to long stem forage only, not other feed. The laminitic horse’s entire diet must still be low in sugar and starch, and each component should still be below 10% NSC.

However, we are now understanding that preventing horses from “grazing continuously” (consuming long stem forage, which is their natural and instinctive way of eating) is a major contributor to laminitis, not a treatment for the condition. 

There are cases where horses or ponies over-eat, and this can lead to unwanted weight gain.  For these situations, we recommend still offering your horse free forage access but using a strategy such as a small hole hay net to slow down their intake.

As we have known for a long time, the primary cause of laminitis in horses is raised insulin levels.  In general terms, insulin levels rise as a result of consuming sugars and starches, which is why removing starches and sugars from the diet of a horse with laminitis is so important. However, we are now learning that horses’ insulin levels are also increased by other things besides sugar - and the biggest contributing factor to fluctuating insulin levels is stress.

Stress is a contributor to laminitis in horses

Horses may experience stress in many forms, such as intense exercise or training, travel, extremes of heat and cold, pain - even psychological stressors such as separation anxiety or fear can cause stress in a horse. In fact, having an empty stomach is a major cause of stress in horses.  

This is new and groundbreaking information in both the treatment of horses with Laminitis, and also in the treatment of gastric ulcers. 

Horses are designed to graze continuously throughout a 24-hour period, ambulating as they search for and chew their food.  In fact, horses in the wild have been observed to graze for up to 18 hours a day, only consuming water once or twice a day, and only resting for a few hours at a time.  However, our domesticated horses are often confined to small areas for up to 22-23 hours per day and additionally have their food consumption restricted to 2 or 3 large, calorie dense meals, which means they revert to having an empty stomach in between meals.  A fatter horse may be given even less food in each meal, and can sometimes only be fed once a day with a small, forage-free meal in an attempt to keep their weight down.

An empty stomach triggers the stress cycle in horses

For horses, as soon as the stomach empties, they become stressed.  Once stressed, the body releases cortisol and adrenaline.  The release of cortisol (the stress hormone) and adrenaline (the fight or flight hormone) triggers the stress cycle in the body. The stress cycle causes the body to look within for energy, and release glucose stored in the liver and the muscles into the bloodstream.  It is this release of glucose from the body into the bloodstream which causes an increase in insulin secretion. The horse ends up with a blood stream full of insulin, often at even higher levels than if they had eaten a high-sugar meal. 

This chain of events is how stress and starvation result in horses having higher blood sugar, which can trigger an increased risk of laminitis. 

Horses suffering from laminitis often also suffer from insulin resistance which makes the situation more complicated. Although the blood glucose-raising effects of cortisol are helpful when the body needs more energy in times of emergency, chronic high cortisol levels over time can lead to insulin resistance by consistently raising blood sugar levels and interfering with insulin action.

Insulin helps horses hold onto fat in times of scarcity

From an evolutionary perspective, horses developed a natural resistance to insulin in order to avoid starvation.  If a horse is stressed due to an empty stomach, their blood insulin rises, and the higher insulin levels cause the body tissue to hold onto stored fat to protect against long term starvation, instead of burning glucose from muscle tissue at normal levels. 

Unfortunately, by using extreme deprivation diets in laminitic horses, we are replicating this exact survival response in the horse.  We stress the horse by keeping their stomach empty, and the stress releases cortisol and then insulin into the bloodstream, these high levels of insulin trigger more stress - and slow the metabolism, which means the horse’s body stores more fat – and overweight horses are more prone to laminitis. 

This starvation-stress-fat retention process is a vicious cycle which has claimed the lives of millions of horses. But we can break this cycle, and it is simple and easy to do. 

An empty stomach impacts gut health too

It can take as little as 15 minutes of not eating for the horse’s stress response to ramp up and after two hours of having an empty stomach, excessive acid production begins to cause stomach pain and starts to impact the gut microbiome and interfere with correct functioning of the horse’s hind gut. 

This is an unhealthy state for the horse’s metabolism to be in, and it will immediately start the viscous stress cycle.  

Managing a Laminitic horse’s diet

The best way to manage laminitis (or any other metabolic condition) is to return the horse’s metabolism to its healthy state. To do this, we must provide free-choice long stem forage. 

Returning the metabolism to a healthy state will not happen overnight.  If the horse has been calorie restricted for a long time, it may gorge initially. However it is important to remember that it is not actually the horse being fat which is causing the stress cycle, but the stress of being starved because the horse is fat which is causing the problem. The horse may gain a small amount of weight initially, but because they are consuming low calorie, low starch, low sugar, high fibre content forage, that weight gain is usually safe. 

The exception to this is if the horse is already obese or needing to lose weight in which case we can control intake through a variety of methods such as track systems and small hole hay nets.  We can also lower the calorie and NSC intake of the horse even further by using forages such as straw or soaking your hay.  In my experience, you will see the horse return to instinctive eating at some time between 1 week and 2 months, depending on the existing damage to their metabolism.

Once horses realize they are no longer being starved, and that forage is always available, they will begin to self-regulate their intake and their metabolism will re-adjust to its normal, healthy state. Once this transition happens, the metabolism will function as it should: burning fat for calories and reducing the amount of insulin in the bloodstream.

Exercise is also critical to helping restore the metabolism to a healthy state. This may start with hand walking or turning out in a group and progress to light lunging and riding. As the metabolism transitions the horse will be able to burn fat again and exercise will encourage this process. 

Feeding your horse with Laminitis

Providing free choice forage can be a logistical challenge for owners depending on their facilities. Getting creative with hay nets and slow feeder options is important and there are a lot of resources out there for ideas on how to ensure that your horse never runs out of clean, dry, long stem forage which is low in starch and sugar. It is also important that the diet remains balanced in this transition.  I always recommend a vitamin and mineral balancer pellet such as Digestive VM to ensure that the horse’s dietary requirements are met without adding any additional calories, starch, or sugars.

Poseidon Animal Health’s new product MetaboLize®, is the ideal companion, designed with the aim of assisting to transition a horse’s damaged metabolism back to a healthy state.

In addition, the anti-inflammatory components in Metabolize® are selected with the aim of assisting horses to move more freely and comfortably, which would allow a swifter exercise recovery timeline, and allow them to burn more fat and calories more quickly through movement. 

Good luck with your Laminitic pony or horse, we hope this information has been useful – check our other articles for more information on Laminitis in horses or reach out to our team if you need any help.

Thanks to Zosia Korcz for the image.