What can cause laminitis in overweight horses during summer grazing? | arlo.® Atlas
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Overview
In overweight horses, summer grazing can cause laminitis concerns because lush grass may be high in sugar and starch, especially after cool nights, sunny days or a period of rapid growth. Other factors can also play a part, so it's worth checking the horse's diet, turnout and weight rather than assuming it's only the grass.
Things To Check
1. See whether the horse is on rich pasture for long periods, especially in the early morning, after a sunny day, or when the grass is growing quickly.
2. Check body condition carefully. A cresty neck, fat pads, or a heavy feel around the tail head can suggest the horse is carrying too much weight.
3. Look at how the horse is moving. Reluctance to turn, a stilted walk, short steps, or shifting weight can all be warning signs.
4. Feel the feet and digital pulses if you know how to do that safely. Heat in the feet or stronger pulses than usual can be worth noting.
5. Review any recent changes in feed, turnout, exercise, or routine. Sudden changes can sometimes tip a horse into trouble.
6. Check whether the horse has any history of laminitis, insulin problems, or other metabolic concerns, as these can make summer grass more of an issue.
7. Make a note of any signs of pain, such as lying down more, standing camped out, or seeming uncomfortable when picked up for handling.
Common Causes
The most common trigger in this situation is grazing on lush, sugary grass, particularly in horses that are already overweight or prone to laminitis.
High intake of grass can be more of a problem in certain conditions, such as cool sunny weather, frosty mornings, rapid spring or summer growth, or after a spell of stress when the horse then eats a lot of grass.
Underlying insulin dysregulation or other metabolic issues can also make some horses much more sensitive to pasture sugar, even when the grass doesn't look especially rich.
Less commonly, a different health problem, pain elsewhere in the body, or a sudden change in management can contribute to laminitis risk and should not be overlooked.
What To Do
Reduce turnout on richer grazing if needed and speak to your vet or yard manager about safer turnout options. Many owners find it helpful to limit access to grass at the most risky times of day and to avoid sudden changes in grazing.
Support weight control with sensible feed management, steady exercise if the horse is sound, and careful monitoring of body condition. Keep a simple note of movement, feed, turnout and any foot changes so you can spot patterns early.
If the horse looks uncomfortable, protect the feet from extra strain and avoid working or riding until you're sure it's safe. Even mild-looking signs are worth taking seriously with a horse that may be at risk.
When To Contact A Vet
Contact your vet promptly if the horse is clearly lame, reluctant to move, has hot feet with stronger-than-usual pulses, or seems painful standing or turning. Early advice matters because laminitis can worsen quickly.
You should also call your vet if the horse has repeated episodes, known metabolic risk factors, or you can't reduce the signs after removing access to rich grazing.
Related Questions
How can I tell if my horse is getting too much grass in summer?
What are the early signs of laminitis in horses?
How should I manage an overweight horse on pasture?
Atlas is here to support owners with practical, easy-to-understand guidance. It is not a substitute for professional veterinary advice. If you're concerned about your animal's health, symptoms worsen, or something doesn't feel right, contact your vet.