Change grain and hay gradually over the course of at least a week

How to change over your horse’s feed

Sudden changes in feed can upset your horse’s digestive system. According to a Webinar given by SmartPak, 10 Guidelines for Smarter Feeding, changing a horses hay suddenly can increase the risk of colic 10 times; other changes in feed raise the risk of colic 5 times.

Why does changing feed have the potential to affect horses so significantly? It’s all has to do with your horse’s intestinal bacteria. A horse ferments its feed in its hind gut and develops bacteria that is specific to what it is being fed. The microbes break down the feed that was not digested in the small intestine. When you suddenly change feeds — even hay — the horse may not be able to adequately digest the new feed because it lacks the proper microbes; in addition, the existing bacteria can die off, releasing acids and endotoxins that can disturb the gut environment and cause colic or even, potentially, laminitis.

  • Introduce all new feed gradually to give your horse’s digestive system the chance to adjust.
  • If you are feeding two pounds or less of a concentrate, you can change over at the rate of 1/2 pound every two to three days. In other words, you add 1/2 pound of the new feed to your horse’s rations the first day. On the third or fourth day, add one pound of the new feed, until you are completely switched over.
  • Horses that are fed larger amounts of grain can be switched over on a similar schedule using 25% of the ration.
  • If your horse is prone to stomach upset or colic, switch more gradually. Some people recommend switching over 25% of the ration and feeding that amount for the entire week before adding an additional 25%.
  • With hay, it is also ideal to add new loads of hay gradually, especially when going from a lower-nutrient first cutting to a higher nutrient second cutting. If you do not have the opportunity to switch the hay gradually, consider soaking the hay before feeding.


  • Whenever you buy a horse, ask the owner for enough grain and hay to allow a gradual shift to the horse’s new rations.
  • Feeding a digestive supplement with probiotics can also help your horse through feed changes.
  • Some complete feeds now include a probiotic but it might not be enough to settle your horse’s digestive system during a changeover.




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