Avoiding a Hay Belly

I’ve often heard, ‘my horse has a hay belly, what should I do differently?’ Or,” he’s really big in the belly but he doesn’t have good muscles.”   Apart from a broodmare belly, post-colic surgery effects or a parasite situation, the answer sounds like a nutritional imbalance.  The good news is, once you know what a nutritional imbalanced hay belly is and what causes it, you can make adjustments in your program and avoid it in the future.

What does it look like?

Willow has had 4 foals, and as a result, tends to show characteristics of a hay belly.
Willow has had 4 foals, and as a result, tends to show characteristics of a hay belly.

Have you ever seen a young or growing horse with a big belly while the rest of their body looks small? Or a mature horse that has a midsection that hangs low, while ribs are visible and muscles along the back and hindquarter are hard to find?  How about the ‘pregnant gelding’ situation?  All of these are describing a hay belly.  On a regular basis, you should conduct a body condition score on your horse to check for muscle mass as well as appropriate fat deposition in key areas.  It’s important to check all areas indicated, since a rib or belly check alone doesn’t provide all the information.

What causes it?

When too many low-value calories are consumed without adequate protein (including essential amino acids), the body stores the calories as energy in cells yet the needed protein isn’t available to maintain muscle mass. In the absence of adequate protein, muscles atrophy while stored energy increases. Over time, a hay belly emerges as muscle mass over the top is lost and gut size may expand.

The biggest factor is overfeeding fiber high in Neutral Detergent Fiber (NDF) while under feeding adequate levels of quality protein. NDF is a measurement of cell wall content in plants such as grasses.  As the plant matures, it builds up stronger cell walls so that it may hold itself upright.  The stronger these walls, the less digestible these cells are for a horse.  So when fed very mature hay, your horse is less able to digest that hay, as compared to hay with a lower NDF value (less mature).  In addition to being higher in NDF, the grasses also tend to be lower in the quality proteins; important nutrients for developing and maintaining muscles.

How to prevent a hay belly

First, feed the best quality hay that you can find in the correct amount for your horse’s body weight, age and activity level. The hay that is smooth and ‘leafy’ tends to have levels of NDF that are better for the horse to digest. Hay that is pointy to the touch or looks like it’s a green version of straw should be avoided as it simply offers little nutritional value for the horse.

How do I get rid of a hay belly if my horse has one?

First, check the quality and quantity of hay your horse is eating. If the quality is adequate, then it’s time to reevaluate the quantity fed.  A horse should be fed 1.0-1.75 pounds/100 pounds of body weight of hay per day.  Not a fan of math? Yea, me neither.  Here’s a quick answer: for a horse weighing 1,000 pounds, that would be between 10-17.5 pounds of hay each day, ideally divided into 2 or even 3 feedings. Check to be sure you’re not inadvertently overfeeding, or underfeeding if your horse is actually bigger than 1,000 lbs. Learn to estimate your horse’s weight accurately here.

The last piece of the puzzle is feed. Make sure that the concentrate you provide is offering adequate quality protein.  Total protein alone can’t support or develop ideal muscles.  The right balance of amino acids is needed to build and maintain muscle quantity and quality.  Look for feeds that guarantee levels of Lysine, Methionine and Threonine.  These three key amino acids are the most important for your horse. And lastly, check to be sure you’re feeding the appropriate amount of concentrate.  Feeding a balanced diet and adding some exercise to help develop muscle mass and tighten up that tummy is a great way to reclaim that belly!

3 Replies to “Avoiding a Hay Belly”

  1. I feed the appropriate amount of timothy/orchard/alfalfa, and fuel. Most horses look great. Two have saggy big bellies, yet no top line…so they show ribs slightly. These horses are never ridden, and no matter how much their feed/hay is increased, they remain the same. Shouldn’t it also be emphasized how important proper exercise is to maintain muscle & fitness? People read articles like this, then ask barn owners to up the feed/hay more and more. Many do not comprehend the feed/hay ratio for weight of horse. Feed is very important, but so isn’t proper, consistent exercise.

  2. Yes I’m from AZ , and I have two young horse about one year old now , but it seem like they had hay belly for two months now our more ,and I dont have much money to go to the vet, but I had feed them some grains and deworming them, and different supplements, I need help or is there other ways I can help with haybelly? Please than you ..

    1. Hello Carolyn, Thanks for the question. We highly recommend that you visit with your regular equine veterinarian to rule out any medical issues anytime you have concern.

      From a nutrition standpoint, your young, growing horse’s digestive system isn’t as adept to digesting fiber as it will be when they are older. It could simply be that your young horse’s diet is too high in indigestible fiber from the cutting of hay you are feeding. We recommend implementing the following diet changes:

      First, trying to locate a cutting of hay that has more digestible fiber. If your hay supplier has had the hay tested, this can be seen by looking at the ADF value, ideally we’d like to see the ADF lower than 35% for young growing horses. Remember, anytime we change forages we want to do so gradually by mixing old and new hay over a week to 10 days.

      Second, you’ll need to find a feed suited for young growing horses that complements the hay you are feeding. A feed specially designed for young growing horses will contain calorie sources that are easier for the young horse to digest. Many times a diet consisting of 60% forage/hay and 40% feed/concentrate is appropriate for the young growing horse. Most importantly as you gradually increase the young growing horse feed, make sure you are feeding enough of it daily to each young horse per the manufacturers instructions located on the tag. For example, an 800# yearling would need to consume at least 6-8# per day of most quality feeds designed for young growing horses.

      We hope this information is helpful. If you have further questions, please let us know!

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