UK free shipping above €100, orders before 14:00 are shipped same day

My horse has insulin resistance (IR) – is it still safe to graze?

Horses with insulin resistance (IR) are at greater risk of laminitis than horses with an optimally healthy sugar metabolism. A horse with IR, recognizable by, for example, a hard mane comb and fat pads at the tail, may not graze unrestrictedly on sugar-rich grass. But can you never put such a horse or pony in the meadow again? Or are there still options? After all, many horses are very happy with grazing…

We as owners like to make our horses happy. But unfortunately unlimited pasture time is not for every horse. Cold-blooded horses, ponies and horses that have previously had laminitis are particularly at risk for the painful condition laminitis.

Does my horse have IR?

A horse that is insulin resistant cannot properly process the sugars from food (such as grass and concentrates). This leads to fat storage, infections and energy loss. The pancreas is also overloaded. Prolonged stress, intestinal infections or hormone problems can trigger IR. Cold-blooded breeds and ponies are often more sensitive to IR than other horses.

Horses with IR can be recognized by:
– Hardened and thickened mane comb
– Fat pads at the base of the tail
– Chafing and itching
– Short and stiff in the movement
– Hard muscles
– Thickening navel (mares) or socket (geldings)
– Often overweight, but not always

Not in the pasture if the sugar content is high!

Horses with IR also like to graze. In some cases this is possible, but you have to manage it very well, monitor your horse well and consult with your vet. The sugar content of grass varies greatly. Under some circumstances, the sugar content is not that bad and an IR horse can go out on the pasture for a short time. Under other circumstances you should absolutely not want that.

The sugar content in grass is lower on average:
– Between 03:00 at night and 10:00 in the morning
– During the summer
– When the grass is a little longer
– With certain types of grass
– If there is enough water in the soil

The sugar content in grass is highest:
– When the grass is stressed by overgrazing
– When the grass is stressed by drought
– In early spring and in autumn
– On sunny mornings after it has frozen overnight
– When the grass is very short
– If the grass has a lot of seed/ears
– If the meadow has been treated with fertilizer

Grazing at night?

Sugar in grass is created during the day, when the grass plant uses sunlight for photosynthesis. Sugars and starches produced during the day are used by the grass for growth in the evening and at night. The sugar peak is often when the plant has been growing all day, around late afternoon, early evening. From about two hours after sunset, the sugar content decreases and at the end of the night there is relatively little sugar in the grass. Even if there are several (heavily) cloudy days in a row, the grass will be less sugary on the second or third cloudy day. This also applies to grass that is always in the shade during the day, for example under a large tree. So if you want to graze a horse with IR, it can be done for short periods at night or in the early morning, in a shaded area, or if it has been cloudy for more than 24 hours.

Good build up and monitor

Always build up grass for an insulin-resistant horse very carefully. Start with five minutes and gradually build up. Always choose a time when there is less sugar in the grass, such as late at night or early in the morning. If your horse has been able to stand on the pasture for a little longer, a grazing muzzle can help to further limit the absorption of grass. But even then you should not put an IR horse in the meadow if the sugar content is high!

manage pasture

Grass that is in the so-called ‘growth phase’ uses sugars for that growth. This means that less sugars are stored in the grass stems. Horses can therefore best graze in pastures that are in this ‘growth phase’. Not too short and not too long. Grass that blooms must be mowed first. If it starts to grow again afterwards, it may be suitable at the favorable times of the day to let IR-sensitive horses graze for a while. It is also wise to check which types of grass and herbs are in your pasture. There is a lot of difference in sugar storage between the different plant species. Note that grass often produces a lot of sugar during drought. A dry turf is therefore not always safe! Strip grazing can be a solution to limit the amount of grass that horses can ingest at one time.

Movement is essential!

The following applies to all horses with IR: keep them moving! It is of the utmost importance that these horses get enough exercise and do not become overweight. So train them regularly and make sure they have enough free movement, even when they are not in the meadow. For example in a paddock with enrichment or a paddock paradise.

IR horse support?

There are several options to support your horse with IR. First, it is wise to give a mild detox twice a year with nettle extract. This helps to remove waste products and strengthen the immune system. In addition, cannabinoids from the clove plant can help reduce inflammation and restore metabolism. Cannabinoids act on the horse’s endo-cannabinoid system, which is vital for all vital functions, including the immune system, the gastrointestinal tract and the nervous system.



Paul Siciliano et al. Effect of Sward Height on Pasture Nonstructural Carbohydrate Concentrations and Blood Glucose/Insulin Profiles in Grazing Horses. Journal of Equine Veterinary Science, vol. 57, pp. 29-34, 2017.

  1. Raymond J. Geor. Nutrition and Exercise in the Management of Horses and Ponies at High Risk for Laminitis. Journal of Equine Veterinary Science, vol. 30, p. 463–470, 2010.

Close menu