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Feeding Tips from Dr. Juliet Getty

Horses that graze all day on Pasture eat more slowly

If you let your horse out to graze on pasture for only a few hours each day, and provide hay the rest of the time, you’ve likely noticed how he approaches the grass like a vacuum cleaner, barely lifting his head the entire time he is outside. On the other hand, horses who graze on pasture 24/7 are more relaxed, eating less grass at a slower pace, taking time to rest and interact with buddies.

Researchers at North Carolina State University were interested in just how much pasture horses consume at varying combinations of pasture and hay availability. What they found confirms what we have all witnessed. At varying levels of pasture turnout, an 1100 lb (500 kg) horse will consume the following amounts of grass dry matter (all horses were given free choice hay when removed from pasture):

  • 24 hours/day: 0.77 lb per hour (0.35 kg/hr)
  • 9 hours/day: 1.32 lb/hr (0.6 kg/hr)
  • 6 hours/day: 1.65 lb/hr (0.75 kg/hr)
  • 3 hours/day: 2.2 lb/hr (1.0 kg/hr)

The less time you allow for pasture grazing, the more excited your horse will be at the opportunity to have fresh grass and will eat nearly three times faster than if he had access to pasture 24/7.

Note: To convert lb/hr to kg/hr, divide by 2.2


Which should be fed first – hay or grain?  If you’re feeding correctly, this issue is truly a moot point because the horse should have access to forage (hay and/or pasture) 24/7 with no gaps. Therefore, when fed concentrates, the horse’s digestive tract should already have hay flowing through it.

If fed starchy cereal grains (oats, corn, barley, etc.) on an empty stomach, the horse will produce even more acid (potentially leading to ulcers) and it will be leave the stomach quickly. When this happens, there is a risk that it will not be fully digested in the small intestine (especially if large amounts are fed), and end up in the hindgut where starch can be fermented by the bacterial population. This can lead to endotoxin-related laminitis.

If hay is present in the stomach first, it creates a physical barrier for the grain to move out of the stomach as quickly. Starch does not get digested in the stomach so the grain is simply mixed and churned into a semi-liquid mass, which enters the small intestine where it can be digested down to glucose. If there is hay present, fiber mixes with the starch and the whole mass enters the small intestine. Fiber is not digested until it reaches the hind gut, but its presence slows down the digestion of starch, and obstructs the absorption of glucose into the bloodstream, leading to a less dramatic rise in insulin.

One thing to note – there is more water involved when hay is present (from increased drinking and saliva production). This is a good thing since digestion within the small intestine cannot take place without water.


“For an adult horse with moderate activity, feed .75 to 1.0 lbs per 100 lbs of body weight.” These are the feeding instructions for a popular commercially fortified feed. If your horse weighs 1100 lbs (500 kg), you’ll need to feed 8.25 to 11 lbs of feed per day. For enough calories? Enough protein? Enough vitamins and minerals?  Yes, to all of the above and more. That’s a lot of feed!  That could amount to three to five two-quart scoops (depending on the weight of the feed) per day. And you’ll need to divide it into multiple feedings since meal size should never exceed 4 lbs (your horse’s stomach is small compared to the rest of his digestive tract).

Chances are excellent that you don’t feed anything close to the suggested amount.  Does it matter? Yes. Most of what you pay for when you buy a fortified feed, are the fortifications. You pay for the vitamins, the minerals, and any special ingredients such as flaxseed and soybean meals to provide omega 3s and protein. The only way your horse will benefit from these nutrients is to feed according to directions. Modify them and you’ll need to “supplement the supplement.”  For example, this feed provides 100 IUs of vitamin E per lb. If you fed half of the recommended amount, say 5 lbs, your horse would only receive 500 IUs per day. That’s the bare minimum, according to the National Research Council, for a 500 kg horse. Most equine nutritionists agree, however, that this horse at maintenance would do better at amounts closer to 1,000 IUs per day. Furthermore, as activity increases, so does the vitamin E requirement. Therefore, supplementation would be appropriate.

Other nutrients such as omega 3 fatty acids, vitamins A and D, minerals such as copper and zinc, and a host of feedstuffs provided to offer enough fat and protein, may need to be supplemented when less than recommended amounts are fed. As you can imagine, it becomes very tricky to figure out just how much to supplement. You could simply give half the supplement dosage if you are feeding half the fortified feed dosage. But to do this accurately, you should figure out how much your horse would have gotten if fed the recommended amounts, and then calculate how much supplement to feed to make up the difference. If you’re not comfortable with crunching numbers, your best source of information would be a qualified equine nutritionist.

Bottom line… pay attention to labels, weigh your feed using a scale, not a scoop, and keep your calculator handy when making adjustments that supplement the supplement.


Regardless of the weather, horses require a daily supply of salt. In cold seasons, salt helps promote enough water consumption to prevent dehydration. In warm seasons, salt replaces what is lost from perspiration. A full-sized horse requires at least one ounce (two level tablespoons or 30 ml) of salt each day for maintenance, this much provides 12 grams of sodium. Heat, humidity, and exercise increase the horse’s need.

There are several ways to accomplish this. The best ways include offering free-choice granulated salt, or adding salt to your horse’s meal (for palatability, limit the amount to no more than 1 tablespoon per meal). A salt block should be available should your horse want more. A plain, white salt block is preferable, but many horses do not lick it adequately since it can be irritating to the tongue. Mineralized blocks often go untouched due to their bitter taste; however a natural sea salt block is often preferred.

Calculate the amount of sodium your horse is getting from any commercial feeds or supplements and add salt accordingly. Always have fresh water nearby.