At 25 my warmblood was diagnosed with chronic tying up. In my 50 years with horses I had never had a horse tie up before. My Vet feels its part of the PSSM syndrome. He suggested adding corn oil or vegetable oil to her feed to increase her fat intake. She won’t eat the oils so even though she is
a chubby warmblood I have her on gleam and gain to add fat.
I also have her on the maximum dose of Vit E and Selenium.
But the most important supplement I added was DMG. Since adding that she has not had a tying up episode. It is thought to help eliminate lactic acid build up. Be aware they pee a lot on this but she has been 2 years without tying up.