Best supplement to prevent gastric ulcers

Gastric ulcers are a little tricky, because they come down to several different things. What you can do is feed plenty of forage and little to no hard feed. Make sure the horse has eaten forage shortly before you work it, so the stomach is full, otherwise the acid can slosh around and cause ulcers in the upper part of the stomach, which has no protective lining. There are also studies suggesting that lucerne helps prevent gastric ulcers, so adding a kilo or two of lucerne to the ration is the best supplement. Good luck!