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Forage FalsehoodsBy Kentucky Equine Research Staff · November 5, 2001

You've spent the afternoon pushing the Lawn-Boy around the yard. As you guided the purring mower to and fro, you quietly thanked yourself for buying the model with the canvas collection bag, saving yourself hours of raking and blistered hands. Suddenly you have a bright idea. Wouldn't your old gelding love those grass clippings? But wait, didn't old Uncle Fred warn against feeding clippings to horses? Something about colic, right? Or was it founder?

Modern day feeding practices are as much about tradition as they are about science. Nothing may rattle the ego of an old-time horseman more than when one of his tried-and-true feeding practices is refuted by a mere whippersnapper, a newbie, or worse, a scientist. In an instant, his ire escalates and a full fledged frenzy–a feeding frenzy of sorts–may commence. While some old-fashioned feeding practices remain pertinent in this day and age, others have fallen by the wayside. Over the last several decades, research has debunked some commonly held beliefs concerning the nutritional management of horses.

First Course

A few pervasive myths regarding feeding forages still abound, despite the domestication of horses thousands of years ago and volumes of research. One that circulates in some show barns and racing stables is that hay is mere filler and not nearly as crucial to the horse's nutritional well-being as the concentrate or grain portion of the diet. In the same vein, some horsemen view hay as a pacifier of sorts, something to keep horses occupied, particularly if boredom may raise its ugly head in the form of cribbing, stall walking, or some other vice. Both reasons are misguided.

Whether it is in the form of hay or pasture, forage should be the mainstay of any equine diet, and all other feedstuffs should complement the forage. In general, horsemen should focus much of their attention on providing the highest quality forage for their charges, be it lush, well-maintained pasture or appropriately preserved, nutrient-dense hay.

Opinions abound as to what hay is best for horses. The most appropriate hay for horses is one that combines optimal, but not excessive, nutrition and economy. In short, the cheapest, highest quality hay that gets the job done is the most suitable. In some situations, a mixed grass hay does the trick, while in other instances only an alfalfa or an alfalfa blend will work. One popular misconception, especially among older horsemen, is the belief that timothy hay is superior to other hays. Timothy hay is perfectly suited for many horses in a variety of situations, but the same level of nutrition or perhaps even a higher one may be found more economically in other hays. On a cost per nutrient basis, timothy hay is often the most expensive hay on the market.

Alfalfa Demystified

While many people feed alfalfa exclusively, especially on the West Coast, some horsemen hold steadfastly to the belief that only grass hays are appropriate for horses. This is unfortunate because legume hays such as alfalfa and the more obscure and less widely available clovers (including crimson, red, sweet, and others), lespedeza, and birdsfoot trefoil can fill a void in the diets of some horses, particularly those with increased energy needs.

Alfalfa hay is snubbed for a variety of reasons, including the misbeliefs that it induces respiratory problems, that all alfalfa is laced with toxic blister beetles, that overconsumption of prime alfalfa is responsible for colic, that alfalfa leaches calcium from bones and promises the onset of arthritis, that youngsters fed alfalfa hay are destined for rapid growth and developmental orthopedic disease, and that alfalfa will evoke irreparable renal disease. High quality alfalfa hay that is fed appropriately does not cause any of these problems.

Alfalfa typically has a rich nutrient profile. Chock full of energy, protein, and calcium, especially when compared to its non-leguminous counterparts, alfalfa has found a niche in the diets of horses that demand high energy rations, including growing horses, mares in early lactation, and intensely worked performance horses. Alfalfa does contain high levels of calcium and low levels of phosphorus. Thus, the entire diet, including concentrate, must be balanced carefully to ensure proper calcium to phosphorus balance. Feeding alfalfa hay with no phosphorus supplementation could precipitate metabolic bone disorders.

Alfalfa hay provides large quantities of protein to the mature horse, in some instances as much as twice the amount necessary for maintenance of protein-mediated body functions. A common fallacy centers around how the horse processes this protein profusion. Some horsemen believe that this overabundance may unnecessarily tax the kidneys because horses that consume alfalfa as a primary forage source do urinate more frequently than other horses.

A by-product of protein metabolism is nitrogen. Excess nitrogen is excreted in the urine, but no ill effects to the kidneys have been documented due to increased frequency of urination. In terms of husbandry, however, the stall of a horse fed heaps of alfalfa may have a more pungent smell of ammonia due to the high concentration of nitrogen in the urine. This does lead to stable-keeping inconveniences as more bedding will be used and closer attention to water availability must be given.

According to a recent study in Texas, alfalfa hay may be responsible for the formation of enteroliths. If large enough, these stone-like masses may impede passage of ingesta in the gut and may lead to colic. Arabians and Miniature Horses are seemingly more prone to enteroliths than members of other breeds. Horses that spend little time grazing and consume diets high in alfalfa also appear to be more susceptible. Chemical analyses cite calcium as a component of enteroliths, which makes alfalfa, a forage well document-ed to have significant calcium content, a logical but unsubstantiated claim. On the other hand, a study of enteroliths collected from 13 horses in California revealed that magnesium phosphates rather than calcium phosphates were the minerals most abundant in enteroliths. A definitive explanation for enterolith formation has not been documented. The practice of feeding vinegar is not effective in eradicating enteroliths based on the Texasstudy.

Other Feared Forages

A bias against coastal Bermudahay remains in the minds of some hay buyers because it has been implicated in several cases of impaction colic. However, the actual hay is not to blame. Rather, the problem may be linked to an error in production. If coastal Bermuda grass is allowed to mature before it is harvested for hay, it becomes too coarse for horses to digest efficiently. Fibrous remnants may accumulate in the gut, creating a bolus that inhibits the passage of other ingesta. This blockage is the basis for impaction colic.

There is much to like about fescue, including tolerance to temperature variations, moisture extremes, and heavy grazing, but a well-founded stigma is associated with this forage. In some climates, fescue can harbor an endophyte (a mold that grows inside the plant) that causes toxicosis in pregnant and lactating mares, as well as young horses.

Prolonged pregnancies, thickened placentas, weak or dead foals, and decreased milk production are signs of toxicosis in mares. In young horses, consumption of endophyte-infected fescue may slow growth. Careful management of broodmares and young stock on fescue is critical. Mares should be removed from all fescue sources approximately 60 days prior to the anticipated foaling date. Weanlings and yearlings should not be allowed to graze fescue or eat mature hay that contains endophyte-infected fescue. The fact remains, however, that fescue is a suitable forage for other classes of horses, and stands of fescue may remain vigorous after other pasture plants have dwindled. Therefore, the notion that fescue is troublesome for all horses is inaccurate.

Extensive genetic research has led to the development of endophyte-free fescue varieties. Complete renovation of pastures is necessary to create a mold-free fescue field, and allowing a field to rest a year or two prior to planting an endophyte-free variety is best. Interestingly, noninfected fescue is not as hardy as infected fescue. Compromises in the qualities that make fescue well-suited for horses (flood and drought resistant, high productivity, traffic endurance) have downgraded the usefulness of mold-free fescue in the minds of some farm managers.

Forage Forms

Much of the dried forage fed to horses is processed into small, easily moved square bales. However, hay can also be stored as large round bales that weigh appreciably more, 500-2000 pounds. Some horsemen dismiss round bales as unsuitable for horses without regard to hay quality. This is unfortunate because round bales have a valuable place in some horse husbandry situations. Free access to the hay eliminates daily feeding (although horses should be given a daily once-over for injuries) and this fact may outweigh the one obvious drawback, wastage. As much as 30% more hay is wasted when fed as round bales when compared to hay fed in alternate ways, but in the cold of winter the trampled hay around the bale makes a warm, comfortable nest for horses.

Forage can also be fed as hay cubes or pellets. Some people erroneously believe that horses choke more frequently on cubes or pellets than other physical forms of feed. This is untrue. Horses are more likely to choke because of their rate of consumption, not on what they are consuming. Those that bolt their feed, regardless of the form in which it is offered, are more susceptible to choke than horses that eat more slowly. Dealing with a bolter may involve creative management, but frequently all that is needed is a shallow trough that allows the feed to be spread over a wider expanse, thereby rendering the horse unable to devour large mouthfuls at one time. Alternatively, large smooth stones can be placed loosely in the feed tub, which will cause the horse to extract feed from the trough more deliberately, slowing intake.

To this day, some horsemen refuse to feed first-cutting hay. Much of this obstinance is due to the higher weed content that sometimes occurs in this cutting. Weeds allowed to propagate between the final cutting of the previous season and the first cutting of a new season may make for a less nutritious feedstuff. Others avoid first-cutting hay because unpredictable weather patterns make cutting, curing, and baling more of a gamble as spring rainfall may thwart haymaking attempts. If, however, a hay producer is mindful of weed control and baling timetables with respect to weather conditions and if no question of quality exists, then there is no justification for refusing to feed first-cutting hay. In one respect, first-cutting hay may be preferable. In some regions, first-cutting alfalfa hay is less likely to contain blister beetles than cuttings taken after midsummer.

Oh, and by the way, feed the fresh grass clippings if the lawn wasn't sprayed or treated with chemicals. It's best to feed them to less-than-ravenous horses as the fine texture of the clippings may cause greedy eaters to gobble them too quickly. Avoid feeding dry clippings to horses with respiratory ailments as they may evoke an allergic reaction due to their dusty nature. Conversely, moist clippings mold quickly, so they should be fed soon after mowing.

The meshing of time-honored practices, common sense, science, and reliable consultation from knowledgeable equine nutritionists can help horse owners separate feeding facts from fallacies.