With the onset of summer and pastures growing lush, some horses are at risk of pasture-induced laminitis. Laminitis is an acutely painful inflammation of the front hooves, although it can affect the hind hooves as well. Founder is the name given to the resultant tissue damage and complications following one or a series of acute attacks of laminitis.
Symptoms of Laminitis
If just the front hooves are affected, the horse or pony will stand in the “founder stance” with its hind legs well up under the body, carrying as much weight as possible, and the front legs placed forward with the weight on the heels. The animal will be reluctant to walk and will turn by leaning back and pivoting around on the rear legs. If all four hooves are affected, the horse will lie down for extended periods of time and may refuse to get up. Other symptoms include heavy breathing and glazed eyes due to pain. The hooves will feel hot and the digital artery, located over the fetlock joint, will have a pounding pulse.

Horses will not want to move and may be ‘rocked back’ on their hind feet.
Causes of Laminitis
Various situations can cause this affliction. Grazing on lush pasture, overloading on grain, eating lawn grass clippings or drinking large amounts of water when overheated can all cause animals to founder.
Treatment
Identify and remove the problem and call a veterinarian to administer treatment and provide advice on the recovery process. Careful attention to feeding and hoof care is necessary for recovery.
Prevention
Through proper horse management, laminitis can be prevented. Avoid feeding in excess and keep your horse at a reasonable weight. Watch for and avoid grass blooms on pastures; pull horses off the fields and onto dry lots if necessary. Feed hay in the morning and turn horses out after lushness and dew is off the grass. Give horses unlimited access to fresh, clean water except immediately after exercise, when the amount should be regulated.
For more information on keeping your horse healthy:
Alberta Agriculture and Rural Development
Alberta Veterinarian Medical Association
Source Alberta SPCA