Hay Belly



Hay Belly - what it looks like and how to treat it.

Many people believe that hay belly means that the horse is eating too much hay, but this is not the case.

Symptoms of Hay Belly in Horses

Should your horse have hay belly, he will have a distended abdomen. His belly will stick out to the sides and hang down. You may also see his ribs and notice that there is not much body fat padding on his neck, shoulders and haunches. Hay belly is more likely to occur in older than younger horses.

  • Poor coat
  • Distended abdomen
  • Lack of body fat
  • Ribs easily seen
  • Loss of muscle mass
  • Large belly but condition good.

Causes of Hay Belly in Horses

Hay belly may occur when a horse has eaten too many low-value calories that lack sufficient protein. Your horse uses protein to maintain or build muscle. His body will store the calories as energy in his cells, however, without protein he is not able to maintain his muscle mass. The lack of protein will cause his muscles to atrophy and an increase in the amount of energy stored, leading to the loss of muscle mass and increase in gut size.

Low Protein Hay

Poor quality hay or grass can lead to hay belly in horses. The digestive system of your horse is made to extract nutrients from grass and hay. Horses don’t have a way to break down fibre, however bacteria in their large intestine will ferment the hay or grass. Should the quality be lower, it will remain in the large intestine for a longer time period, which leads to the bacteria having to put in extra work in order to extract as many nutrients as possible. The extra fermentation that this causes will lead the belly to distend.

Other Potential Causes

A distended abdomen is also seen in horses that have worms. This is not considered hay belly and is a different problem. Your veterinarian can assess the muscle mass of your equine if you are not able to and may palpate the abdomen as a part of the physical examination. He may recommend evaluating a faecal sample and suggest a blood analysis to rule out other illnesses that can be present similarly, such as a parasitic infestation.

A distended stomach can also be seen in in-foal mares and some may call that hay belly, which is not correct.

Diagnosis of Hay Belly in Horses

If you notice that your horse has a big belly and little muscle mass, it is likely his food is of poor quality and he has hay belly. When a horse is healthy he will not lose muscle mass, even when not ridden for significant time periods.

Treatment of Hay Belly in Horses

Should you notice that your horse has a big belly while losing muscle mass, consider doing the following:  

  • Begin feeding him a better quality of hay. If your horse is on pasture, provide him good quality hay as a supplement to his grazing.
  • Feed your horse quality protein sources such as freshly ground linseed, hemp meal, lupins, sunflower seeds or a mixture of all of these.


If you are unable to provide good quality hay or are unsure of its quality, we would recommend begin feeding our suggested protein sources in an amount appropriate for his size, weight and age so that he is able to get the protein he needs.

We recommend consulting with your equine nutritionist or health professional for advice on your equine’s diet as it is important to avoid feeding your horse too much hard feed as that could lead to colic and/or founder.

Grain or other forms of feeds should only be used to supplement and not as the only source of food. Hay is should form the basis of your horse’s diet.

Regularly reassess your horse’s condition and add more protein as needed. His requirements will change with workload and season.