Forage Substitutes For Horses

Agdex#:	460/60
Publication Date:	09/05
Order#:	05-055
Last Reviewed:	09/05
History:
Written by:	Dr. Sarah L. Ralston, VMD, PhD, dACVN - Associate Professor/ Department of Animal Science/Rutgers University College/New Brunswick/New Jersey; Dr. Bob Wright - Lead Veterinarian/Disease Prevention/Equine and Alternate Species/OMAFRA

Forages, such as long-stem hay and/or pasture grasses and legumes, are the traditional cornerstones of horse rations. A good source of forage should comprise at least 50% of a horse's daily intake - 5.4-6.8 kg (12-15 lb) of dry hay for the average adult horse. Although forages are an important source of energy, protein, minerals and vitamins, they also provide fibre - a "nutrient" that horses also require. Long-stem hay and pasture grasses contain over 20% crude fibre, whereas most grain mixes, even so-called "complete" feeds, contain less than 12% fibre. Horses can adapt to balanced rations that do not contain hay or pasture, but the absolute minimum of fibre necessary has not been established. However, low fibre/high concentrate rations have been documented to increase the risk of colic and gastric ulcers and will dramatically increase a horse's desire to chew wood.
Unfortunately, in times of drought or other adverse weather conditions, long-stem, dust-free hay is not only expensive but hard to find.

Alternatives To Long-Stem Dry Hay

Luckily we do have some options. Listed below are some forage "substitutes" that can safely be incorporated into horse rations to provide the necessary fibre.

Haylage, Grass Silage and Preservatives

Haylage is produced by the ensiling process, which consists of cutting, partially wilting and placing young respiring plants in a silo or container, such as a plastic bag, where the air is eliminated. The hay is baled at about 45%-50% moisture and immediately wrapped with plastic or placed in a bag, to reduce the presence of oxygen. The plants consume the remaining oxygen in the bag, lowering the pH, and the forage goes into a suspended state. The pH should be below five. Should the bag become punctured, secondary fermentation will start, and the haylage will become spoiled in areas where there is oxygen. Ensiling maintains the quality of the forage as it was cut. It is usually high in energy and protein because the cutting date is not dependent on the weather. The high moisture level and lack of dust are useful when feeding a horse with heaves.

However, there are some major disadvantages to haylage:

• Very little research has been done on the feeding of haylage to horses, although many horse owners have been feeding it successfully with few problems. There are outstanding unanswered questions about the effect of an acidic feed on horses and the possibility of causing colic by feeding them frozen silage.
• Ensiled bags or bales are almost twice as heavy as bales of dry hay, due to the 50% moisture level.
• Individually bagged haylage must be moved carefully to prevent damage to the integrity of the bags and the resultant secondary fermentation. Any time the bag or plastic is pierced, oxygen will enter and spoilage will occur.
• There is danger of botulism. Horses should be vaccinated for botulism prior to being fed silage. See the information sheet Hay, Haylage and Treated Hay for Horses on the OMAFRA web site.

Preservatives of various types, e.g., proprionic acid, are applied to hay during the baling process when it is difficult to dry the hay below 15% moisture content. The preservatives, when used properly, allow the storage of hay at a higher moisture content level than dry hay. Only proprionic acid preservatives have been studied for feeding to horses. Horses prefer non-preservative-treated hay when given a choice but will consume equal quantities of either when not given a choice. Proprionic acid is normally produced in the gastrointestinal system of horses.

"Complete" Concentrates

Available in textured, pelleted or extruded forms, complete concentrates are mixtures of grains, hay or beet pulp, vitamins and a mineral supplement. They are designed to be fed without hay, grain or other supplements and still meet the horse's basic needs. Since "complete" concentrates are available in a wide variety of nutritional profiles, be sure to read the labels to make sure they are suited to your horse's requirements (e.g., an adult horse for maintenance vs. a growing or performance horse). The label should contain the statement "designed to be fed without forage." (Do not confuse complete concentrates with concentrates that are mixtures of grains only designed for feeding with hay or other forages.) Unfortunately, none of the complete concentrate products that the authors are aware of contain sufficient fibre to satisfy the horse's need to chew. Fibre deficiency will cause dramatic increases in wood-chewing activity.

Usually 5.4-6.8 kg (12-15 lb) of a complete feed are needed to meet the average 450-kg (1,000-lb) horse's daily needs, which, if split into only two feedings, will overwhelm the horse's digestive capacity. Feeding smaller amounts (1-1.5 kg (2-3 lb) per feeding) more frequently will not only optimize digestion but will also keep the horse more occupied. Use complete concentrate feed instead of, not in addition to, a horse's regular grain ration. Switch horses to the complete concentrate rations slowly, taking over a week to completely eliminate hay from their diet and get them on the amounts of complete concentrate feed necessary to meet their needs.

CAUTION: Feeding horses complete concentrate feed without any other source of roughage may increase the risk of colic and/or laminitis.

Hay Cubes

Long-stem hay, either alfalfa or a mixture of alfalfa and timothy hay, is dried, chopped and compressed into cubes. The cubes are usually sold in 25-kg (55-lb) bags, which are easily transported and stored, making them more readily available from regions where the hay crop was good. Cubes made from a mixture of alfalfa and whole corn plants may also be available. We have used hay cubes as the sole source of fibre in several research studies at Rutgers with good results, feeding up to 5.4-6.8 kg (12-15 lb) of cubes per horse per day. However, there was a dramatic increase in the incidence of wood chewing in every study, and two horses had problems with choking on the cubes when they were fed dry. The wood-chewing can be reduced by feeding at least some long-stem hay or straw. (See the section Straw, right.) The danger of choking is eliminated by soaking the cubes in water for 10 min before feeding them to the horses.

The mixed-grass or corn-plant/alfalfa cubes are recommended if fed as the sole source of forage to adult maintenance horses. Straight alfalfa cubes will contain more protein and calcium than the normal adult horse requires but will not harm the horse as long as its kidneys are functioning properly. Alfalfa cubes are more appropriate for either lactating mares or growing horses and as a partial forage substitute. While up to 6.8 kg (15 lb) or more can be fed per horse per day, 1-2.5 kg (2-6 lb) of cubes per horse per day can be used as a "hay extender" if only poor-quality hay is available in limited quantities.

Straw

While straw - the stalks left over from harvesting wheat or other grain crops - contains very little nutritional value, it is a great source of fibre. If the horse's energy, protein, mineral and vitamin needs can be met by a complete pelleted, extruded or textured concentrate, bedding the horse on straw will satisfy the horse's desire to chew and reduce the amount of wood-chewing activity. If horses have not had access to forage and are suddenly placed on straw, however, there is a serious risk of impaction colic. Think of straw not as a source of nutrition for horses but rather as a "chew factor" and fibre source. Some horses, however, consume a good percentage of their straw bedding. Straw may be contaminated with mycotoxins produced by different fungi. During wet weather, Fusarium, a saprophytic fungus, will invade the heads of grain. Fusarium can produce a number of toxins that are toxic to animals. Very little research has been done on feeding these mycotoxins to horses or the amount that may be found in the straw. Therefore, be cautious about the intentional or unintentional feeding of potentially Fusarium-infected straw. Rye straw infected with the fungus, Claviceps ssp., has caused dystocia (difficulty foaling) in pregnant mares. Do not use rye straw with pregnant mares in the last two months of gestation.

Beet Pulp

In the past 10 years, beet pulp, a by-product of the sugar beet industry, has gained popularity as a supplement for horses. It is a good source of fermentable fibre and is fairly high in calcium, with only moderate protein (8%) and no vitamin content. Beet pulp is available in its "raw" form, which looks somewhat like ground-up old shoe leather, or in pellets. Traditionally, the raw form is soaked in water for 1-12 hr before feeding; this can be a problem in hot, humid weather when the pulp can become rancid. It is a very common additive in "complete" concentrate feeds.

Up to 4.5 kg (10 lb) (dry weight) can be fed to the average adult horse but it should be supplemented with a balanced vitamin/mineral supplement and perhaps protein. Do not feed beet pulp as the sole source of nutrition.

Wheat Bran

Though wheat bran is a good source of fibre, do not feed it to horses in large quantities for prolonged periods of time. It is extremely high in phosphorus and will cause potentially debilitating calcium/phosphorous imbalances. Feeding horses excessive amounts of bran can cause nutritional secondary hyperparathyroidism or Big Head syndrome. Bran is also fairly high in protein (16%). If feeding it as a supplement, limit it to no more than .45 kg (1 lb) per adult horse per day and carefully balance the calcium/phosphorus ratio with calcium supplements. Wheat bran is not recommended as a major forage substitute. Wheat bran can also contain Fusarium-related mycotoxins during wet growing years.

Rice Bran

Recently promoted as a source of fat (energy) for horses, rice bran is also a fair source of fibre. However, it has a higher concentrate of phosphorus per pound than wheat bran. Some commercial rice-bran products have added calcium to correct the imbalance, but, as with wheat bran, rice bran is not recommended as a major forage substitute.

Lawn Clippings/Garden Refuse

Because many ornamental and garden plants (tomatoes, potatoes, rhubarb, etc.) are potentially lethal to horses, these are not recommended as forage substitutes or even supplements. Even pure grass clippings are unacceptable. The small particle size and high moisture content of grass cut with a lawn mower result in rapid fermentation in warm weather. Feeding lawn clippings and garden refuse to horses can lead to colic, botulism, laminitis and/or death and is not recommended.

Summary

Long-stem, dry hay should be the main nutrient source for horses. All the substitutes described in this Factsheet have their drawbacks. Complete feeds and hay cubes are relatively expensive ($200 to $300/ton). It is most economical to use them as "hay extenders," especially if moderate-quality hay is available at a lower price. Neither straw nor beet pulp should be used as the sole source of nutrition. Though they are both good sources of fibre and relatively economical, neither contains the proper balance of nutrients for any class of horse. However, if adequate-quality hay is totally unavailable or costs over $250 per ton, beet-pulp-based complete-concentrate feeds and cubes can be used with straw to provide both the proper nutrient balance and fibre content to maintain gastrointestinal health and well-being. Although bran, from either wheat or rice, is a good source of fibre, NEVER use it as a main component of your horse's diet. Avoid lawn and garden clippings at all costs.

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