In general, keeping a horse in a pasture is much better than keeping him/her in a stall.
Horses turned out have a lower incidence of colic, anxiety, fear and less behavioral abnormalities; however, not all horses can be out on pasture all the time and some cannot be on pasture at all.
Horses with insulin resistance or those that are overweight should not be on pasture at all without a grazing muzzle because most pastures contain large amounts of non-structural carbohydrates or NSCs and fructan is a major part of the NSCs, Dr. Bob Judd, host of Texas Vet News on the Texas Farm Bureau (TFB) Radio Network, said.
Research suggests that ingesting fructan is the main reason horses develop laminitis and founder on grass.
This is because the fructans are not broken down in the upper GI tract but passed to the lower GI tract and are fermented which leads to the problem, Dr. Judd said.
Fructans are high in times of rapid growth of grass in early spring. Fructans are often found higher in the stems of a plant than in the leaves.
Avoid overgrazing to prevent horses from eating close to the ground, Dr. Judd said.
This time of year, as the ground start to turn brown, many people feel it is okay to turn insulin-resistant horses out because the grass appears dead; however, stressed grasses due to grass can contain high levels of fructans.
Dr. Judd’s full report can be heard here: http://bit.ly/1iLSw1M.