Making Feed Changes with Horses

Make feed changes slowly over a period of 7-10 days.  If you have horses, then chances are, you’ve seen this advice before.  But have you ever thought about why we need to make feed changes slowly?  And does this advice apply to forage as well?  That’s what I’d like to delve into in this post.

First, lets talk about how horses differ from us and most animals as far as their digestion goes. . .

Horses are hind gut fermenters.  This means that most of their digestion takes place in the hind gut (cecum and large intestine).  This process starts in the cecum, where there are millions of microbes (bacteria and protozoa) that work to break down fibrous foods.  The food can stay in the cecum to for up to seven hours during the fermentation process before moving on to the large intestine to be further digested.

The microbes in the cecum and large intestine become ‘specialized’ in digesting the food that the horse normally consumes.  Some break down proteins, while others break down complex carbohydrates or fibers. They convert these foods into useable volatile fatty acids (which provide energy), amino acids, vitamin K, and B vitamins.

When a new food is suddenly introduced, it can cause a shock to the microbes, leading to changes in their population and to the fermentation process in general.  Some microbes will die off because the food they were specialized in digesting is no longer available.  Other microbes may multiply, possibly resulting in large quantities of fermentation byproducts that alter the pH in the hindgut.

But the good news is that these microbes CAN handle (appropriate) new foods if they’re introduced slowly.  If we add just a little bit at a time into the diet, the microbes will adjust and become specialized in digesting the new type of food.  This entire process may take several weeks though.  So the key word with making diet changes with horses is patience!

Here are some general rules for making feed changes with concentrates:




  • Add new concentrates at about 1/2 pound at a time, every 2-3 days.  As you increase the new concentrate, decrease the old concentrate.  Depending on the amount fed, this should take anywhere from 1-3 weeks.
  • Reductions in total amount of concentrates should be done gradually over a one- to two-week period, subtracting approximately 1/4 pound of feed every other day.


You might be wondering about changes with grass and hay as well.  Is it wise to make changes slowly with forage too?  In short, yes!  The same rules will apply here.  

Here are some guidelines for making changes with forage:




  • If transitioning from hay to pasture, increase turnout time in one to two-hour increments over a period of several weeks.
  • Feed hay before turning horses out on pasture so they don’t overeat.
  • Take special care when allowing a horse to go from hay to fresh spring pasture as carbohydrate overload can easily occur and lead to laminitis.
  • If possible, transition between different batches of hay slowly as well, gradually adding more of the new hay in with the old hay.


When bringing a new horse home, diet changes are inevitable.   I would suggest trying to purchase a few bales of hay from the previous owner and also finding out what type of concentrate they fed the horse.  Then, you can gradually switch your new horse over to what you feed.   I know this isn’t always possible though–especially with rescue or sale barn horses.   With these horses, just make sure to start concentrates out in small amounts and follow the guidelines above.

Another good idea during times of diet transition is to feed a probiotic or prebiotic.  These will help the microbes cope with the changes in feed.  You can read about the differences between pro- and pre-biotics here.




Sources and Further Reading

Switching Horse Feeds Safely

The Hindgut’s Role in Digestion

Feeding Advice: How to Change your Horse’s Diet Successfully

The Equine  Digestive System 5: Cecum

Havoc in the Hindgut


Hi! My name is Casie Bazay. I'm a mom, a freelance writer, and a certified equine acupressure practitioner.

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2 Responses

  1. Monique Warren says:

    Thank you for all your insightful easy to understand articles. The Naturally Healthy Horse introduces innovative thoughts and principles to improve the lives of beloved equines around the world! Best horse blog ever!

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