Dr. Christina Vittoria explains how a wet summer can cause equine diarrhea and discusses when owners should worry about it.

For many horse owners, the pasture is still green and horses are eating it up. However, the young grass contains more sugar and increases hind-gut fermentation, which can cause loose manure for grazing horses.

“A little bit of loose manure will not harm your horse,” Vittoria told the Reading Eagle. “But you must watch for gas colic or severe diarrhea. Laminitis can be another horrible sequel to eating too much young, green grass.”

Probiotics can aid horses suffering from diarrhea. They are available over the counter, but owners should make sure that they are buying products for hind-gut fermenters. These include probiotics containing Saccharomyces boulardii.

Owners should also ensure that horses dealing with diarrhea remain properly hydrated, including replenishing lost electrolytes, which can be added to their food or water.

“If you add [electrolyte powder] to a water bucket, remember to hang another bucket of just fresh water,” she says. “Some horses don’t want anything to do with what they believe is ‘poisoned’ water.”

Loose manure also can be caused by more serious conditions. Parasites and waterborne insects are also more plentiful with continued rain. Potomac horse fever, which is caused by horses eating waterborne insects that carry it, causes a high temperature and diarrhea.

Regardless of the cause of loose manure, Vittoria cautions that there is a time to call the veterinarian. “If the diarrhea doesn’t clear up with some simple treatments, you may want to call your vet.”