For the second year, a nationwide series of more than 160 gastroscopy events showed 60% of horses were identified with stomach ulcers, according to a press release from Merial.

"This is the second year that these scopings were able to show horse owners the type of potentially painful stomach ulcers that their horses have been dealing with," said April Knudson, DVM, manager of Merial Veterinary Services. "Many times, horses are suffering in silence from stomach ulcers due to their natural tendencies as a prey animal to mask pain."

Veterinarians evaluated the horses' stomachs using gastroscopy. Throughout the year, 1,532 horses across the country participated. Overall, 922 horses from 37 states had some ulceration as identified by gastroscopy.

There are many triggers for stomach ulcer development, and stress is an important factor, Knudson said. Horses may experience stress when exposed to such situations as competition, training, travel, lay-up due to sickness or injury, shows or events, limited turnout or grazing, and trailering