Winter is in full force, and horse owners need to make sure they feed their animals appropriately for the conditions, according to North Dakota State University Extension Service equine specialist Carrie Hammer.

Feeding good-quality hay in sufficient amounts is one of the best ways to help horses keep warm. Feed digestion produces heat, with the digestion of high-fiber feeds such as hay releasing the greatest amount of heat.

High-fiber feeds produce more heat during digestion than low-fiber feeds. Thus, more heat will be produced through the digestion of hay than low-fiber grains such as corn and barley. Although oats are a low-fiber grain, they will produce more heat during digestion than other grains due to their fibrous outer hull.

Providing a sufficient amount of feed is extremely important during the winter because grazing usually is not an option. In general, a mature horse should be fed approximately 2 percent of its body weight per day in total feed. The requirement is higher (up to 3 percent) for lactating mares.

“Owners should plan on feeding 2 pounds of good-quality grass hay per 100 pounds of body weight for the average horse,” Hammer says.

However, the general recommendations of feeding 2 percent of body weight do not account for hay waste or extremely cold weather conditions. Feeding hay in a feeder will result in less waste than not using a feeder. Although many different types of bale feeders are available, using a feeder can reduce waste to less than 20 percent.

If owners assume 20 percent of the hay will be wasted, an average 1,000-pound horse would require 24 pounds of hay per day (20 pounds to meet the recommendations plus an additional 4 pounds to account for waste).

Cold temperatures also change the daily feeding requirement. The lower critical temperature for horses with a heavy winter coat during dry, calm weather is 30 F. For each 10-degree change below 30 degrees, horses require an additional intake of approximately 2 pounds of feed per day (assuming the feed has an energy density of 1 megacalorie per pound, which is typical for most hay).

A 10- to 15-mph wind will require horses to consume an additional 4 to 8 pounds of hay to meet their increased energy requirements. When a horse without shelter becomes wet and encounters wind, it must consume an additional 10 to 14 pounds of hay.

“Considering that a 1,000-pound horse consumes 20 pounds of hay daily to maintain body weight in ideal weather conditions, consuming an additional 10 to 20 pounds or more becomes impossible for many horses,” Hammer says. “Therefore, in extreme conditions, hay alone is usually insufficient to supply the energy demands for a horse to maintain its body weight, and some type of additional grain source is justified.”

Meeting the daily dietary needs is even more difficult if the quality of hay is poor. Most mature horses are idle or see occasional use during the winter and can be fed good- or average-quality hay (think moderately green with a moderate amount of leaves, slightly stemmy). Above-average hay (mostly green, good amount of leaves, few large stems) should be fed to young, growing horses; pregnant mares in the last two months of gestation; and lactating mares.

Poor-quality (brown, few leaves, large amount of coarse stems) and moldy hay should not be fed, regardless of the physiologic state of the horse. Investing in the best quality hay possible usually will save money in the long run because less feed is required to meet the horse’s nutrient requirements and the palatability is higher, resulting in less waste.

“Owners can supply all the poor-quality hay they want and a horse still will lose weight in rough winter conditions,” Hammer says. “Poor-quality hay just doesn’t provide the energy and nutrients a horse needs to survive during a harsh, cold winter.”

Finally, don’t forget to provide water in the winter. An average adult horse will drink 5 to 10 gallons of water per day. Access to clean water is essential to the horse’s health and well-being. During the winter months, horses consume large amounts of dry forage, and reduced water intake will increase the chances of horses suffering from impaction and colic.

Feed intake also is closely related to water intake. If water supplies are limited, feed intake can be reduced, which further puts the horse at a disadvantage in maintaining health and weight during the winter.

NDSU Agriculture Communication - Jan. 29, 2013