EQUINE OBESITY – feeding and care of the obese horse

Equine obesity is a growing problem in the UK horse population and is often called the ‘silent torturer’, with overfeeding and lack of exercise being the main reasons for its increase.  

Fat horse

Obesity is a considerable health risk and can lead to organ damage, osteoarthritis and almost certainly insulin resistance and hyperinsulinaemia both of which are risk factors for laminitis.  The good news though, is that recovery and weight loss can be achieved with the right diet and management. Lisa Elliott (MSc) - nutritionist at Castle Horse Feeds and Smart Horse Nutrition – gives us some essential guidelines to help your horse to combat obesity and achieve the right weight for optimum health and condition. 

Assess weight and condition 
Getting familiar with the weigh tape and Body Condition Scoring (BCS) can help assess your horses body condition and make the right choices for reducing their weight. Research has shown that horses owners can underestimate their horses body condition so it is important to be brutally honest when assessing you horse. Even if it may be difficult to accept, admitting your horse is obese is a crucial step to helping them on the road to weight loss and recovery and to help set realistic goals..

Provide a low energy, high fibre diet – without unnecessary calories
This might seem obvious, but it’s easy to feed extra calories your horse doesn’t need without realising it.  Feeds that are marketed as low calorie may seem like the ideal solution for an overweight horse, but are not necessary. For example, a 500kg horse requires for around 70MJ (megajoules) of Digestible Energy (DE) per day to meet basic maintenance requirements. Hay can range in DE from around 6MJ to 9MJ per kilo, so if a 500kg horse is fed an 8MJ/KG hay at the necessary 2% of its body weight, so 10kg, that horse would be getting 80MJ/DE which is already around 14% above its maintenance requirement just from hay alone! Therefore, it is easy to see how coupled with a lack of exercise, horses can become overweight and eventually obese. Feeding low calorie feeds as an extra will add calories to the diet that the horse doesn’t need and help contribute to weight gain.  

A low energy, high fibre diet - essentially a forage based diet, which reduces calorie intake without compromising on fibre is key to achieving healthy weight loss. Zero grazing is a must for an obese horse but ad-lib low calorie forage such as hay should be offered instead and the horse should ideally be out in a dry paddock to allow him or her to move about.  It's often a good idea to place piles or nets of forage in the corners of a dry paddock so that the horse has to move to get to them. An overweight horse should never be starved as this can lead to serious health conditions.  Additionally, restricting forage to a large degree can be counterproductive and actually make the horse fatter.

Getting forage tested for starch, sugar and energy levels is essential. Obesity will mean that the horse or pony will mostly likely be insulin resistant and at real risk of laminitis if they don’t already have it so starch and sugar need to be kept very low. The higher the starch and sugar, the higher the potential calories the horse consumes too. Ideally forage offered should be less than 10% total starch and sugar or Non-structural Carbohydrates (NSC), but this can be difficult to find so 12% NSC is often more realistic. 

Soaking hay is often recommended to reduce NSC in hay, but results can be variable, normally take hours and reduce hygiene levels, particularly in warmer weather. A better solution may be to feed a specifically produced low NSC (<12%) hay to keep starch, sugar and calories to a minimum and help your horse to slim down.  

Feeding a low energy fibre chop or chaff as a partial hay replacer can help reduce calories. Additionally,  oat straw can provide a very useful low calorie alternative to hay as its energy level is typically around 6MJ/KG, with very low starch and sugar levels, so can be used to provide essential ad-lib forage without the calories. Oat straw can be mixed with hay and ideally used to replace 25% of the hay, but may be increased if necessary to a maximum of 50%.    When straw is fed above this level the risk of gastric ulcers and colic can increase, so for this reason it should never be offered as the sole source of forage.

If necessary, the amount of forage can be reduced to supply 1.5% of bodyweight instead of the normal recommended 2 - 2.5%. However, this still needs to be fed ad-lib potentially through the use of small holed or double hay nets to help it last longer so the horse is never without. 

Use a balancer to supply essential micronutrients
Whist a low-calorie forage based diet is ideal to help combat obesity, it probably won’t provide all the essential micronutrients (vitamins, minerals and amino acids) your horse needs. Balancers offer a sensible solution as they are low calorie in terms of overall calories provided.  For example, the normal feeding rate of a balancer is 100g per 100kg bodyweight, so a 500kg horse would receive just 500g. This would supply just 5MJ of DE, which equates to just 7% of the horses’ daily energy requirements.  Look for a balancer which is molasses and cereal free to keep starch and sugar to a minimum, but with a high specification of micronutrients for optimum health and well-being.

Top tips for managing obesity:
  1. Implement a suitable exercise regime – providing your horse with suitable exercise is one of the most important things you can do to help drop essential weight. For an obese horse, this should be started very gradually and built up to the chosen level once the horse drops weight and becomes fitter. 
  2. Feed for work done not what is anticipated – Feeding unnecessary energy will result in weight gain, so always ensure you feed for the type of work the horse is doing now and not for what may or may not be done in the future. 
  3. Monitor weight and condition regularly – using a weight tape and condition scoring chart to monitor your horses condition regularly can help pick up subtle changes in condition and weight loss or even gains. In this way, the diet can then be adjusted accordingly or not as necessary to ensure the right amount of condition.  
  4. Avoid over-rugging –  horses are supposed to use their fat reserves to keep warm in winter, so keeping rug use to a minimum or turning the horse out without one can help your horse lose those extra pounds. 
Smart Horse Nutrition is part of the tried and trusted Castle Horse Feeds group, a company dedicated to providing your horse with superior nutrition, at an affordable price. 

If you have any questions for Lisa about creating the best diet for your horse, please email This email address is being protected from spambots. You need JavaScript enabled to view it.. See www.smarthorsenutrition.com or www.castlehorsefeeds.com for further information or call 01497 570345.