As spring quickly approaches, we start to see the first signs of green grass growing through the old dead grass of last year. While it’s easy to see the benefits of turning your horses out onto green grass, you need to be cautious about how and when you turn them out. Horses that ingest too much green grass too quickly can easily founder or develop laminitis.
Laminitis is an inflammatory condition of the tissues (laminae) bonding the hoof wall to the pedal bone. This can result in the pedal bone sinking or rotating under the weight of the horse and can even penetrate the sole of the hoof in extreme cases. This condition is extremely painful and debilitating for horses.
At the beginning of the growing season, you should limit your horse’s exposure to green grass; start with about an hour and slowly increase over time. Horses that are predisposed to laminitis such as ponies and older horses as well as those who are over-conditioned or are already diagnosed with a hormonal disease such as Cushing’s, should be closely monitored during turnout. Some horses can consume enough feed in 2-3 hours that would normally be consumed throughout the entire day! Know your horse, and adjust their exposure to green grass accordingly. The best time for turnout is mornings, the sugar content in grass is lower and it will continue to rise throughout the day, peaking usually mid-day.
Early in laminitis, horses are depressed and anorectic. They may resist exercise and have an altered stance. A horse typically carries 60% of its body weight on their front end, which is why may observe your horse rocking their weight onto their back feet to relieve pressure off their front feet. Laminitis more commonly occurs in the front feet but can occur in all four. Even in the acute stage of laminitis, lameness can be quite severe even if no displacement has occurred.
For more information:
Laminitis in Horses
By James K. Belknap, DVM, PhD, DACVS, Department of Veterinary Clinical Scienes, College of Veterinary Medicine, Ohio State University https://www.merckvetmanual.com/musculoskeletal-system/lameness-in-horses/laminitis-in-horses