Is it safe to feed my horse or pony grass clippings?

Horses should never be fed lawnmower clippings.

Although horses eat grass lawnmower clippings should never be fed to your horse or pony this is because grass clippings are fermenting. 

Fermenting grass clippings give off gases which can build up inside the horses stomach and cause colic and other gastrointestinal disorders. 

Horses are unable to vomit or burp and in some cases the gases can  build up to such a point that they can actually cause the stomach to rupture and kill the horse.

Image:  Hedwig Storch  [CC BY-SA 3.0 (http://creativecommons.org/licenses/by-sa/3.0)], via Wikimedia Commons