E-533 12-02

eeding Race Prospects F Racehorses & inTraining

P. G. Gibbs, G. D. Potter and B. D. Scott eeding F Race Prospects & Racehorses in Training

P. G. Gibbs, G. D. Potter and B. D. Scott*

n recent years, significant research attention be closely related to that ’s fitness and diet. has been directed toward the equine athlete, If the horse has the available energy and the Iparticularly racehorses and young des- to use that energy, it can voluntarily run tined for the track. New information is becoming faster and perform at a higher level than horses available and new concepts are being formed with insufficient fuel and other nutrients to per- about the physiology and of racehorses. form these tasks. One reason for this attention is that over the To ensure that racehorses can perform at opti- past 50 years, the physical performance of race- mum levels, trainers need to pay close attention horses has improved very little. Although racing to nutrition, providing the appropriate amounts times over common distances have improved and forms of energy, , and miner- some, the magnitude of improvement has been als for young prospects as well as for racehorses relatively small compared to that of human ath- in training. If the nutritional requirements are met letes. This is in spite of efforts to breed horses accurately and feeding management is conducted with greater racing ability. Further, too many properly, racehorses’ performances will be horses continue to succumb to crippling injuries improved over those horses fed imbalanced diets brought on by acute fatigue and a compromised in irregular amounts at inappropriate times. skeletal integrity. Conversely, the performance of humans improves yearly, monthly and in some cases even Race-bred prospects daily during certain athletic competitions. This To produce and maintain a successful race- phenomenon is explained by the dramatic horse, you must begin with proper feeding and improvements in the diet and training regimens early development of a young prospect. This being developed continually for human athletes. process begins soon after a is delivered. Two Horses also can be expected to perform better vital goals are to promote early growth and sound if they are properly conditioned and fed a bal- skeletal formation. If these goals are to be anced diet containing the fuel (energy) and other achieved, weanlings cannot be fed the same nutrients needed to do the work. A horse that is rations as yearlings, and long yearlings in training “dead fit” and fed a good ration will run as fast must be given mixes that are different as genetically possible if that horse has any from those fed to yearlings not being exercised.16 “heart.” The term “heart” in a horse may in fact A field study was conducted on the manage-

*Professor and Extension Horse Specialist; Professor and Equine Science Section Leader, Department of Animal Science, Texas A&M University; Assistant Professor and Extension Horse Specialist; The Texas A&M University System 1 ment practices of 58 Texas farms raising almost more lysine, and to ensure Once training or forced exercise begins, the training must have adequate energy, protein, vita- 2,000 and quarter horse race-bred that they have the proper nutrient-to-calorie ratio. feeding program should be evaluated even more mins and , and overall feeding must be prospects.5 Most of the owners/managers of those The -to-calorie ratio is more critical than carefully. managed well. farms identified nutrition, exercise and as the calcium-to-phosphorus ratio, which also mer- three major factors contributing to problems such its some consideration. Energy as contracted tendons, epiphysitis or osteochon- A well-formulated balanced feed will most Horses in race training Racehorses often require twice as much ener- drosis. Contracted tendons were reported more likely provide the minimum acceptable amounts Researchers have recently found that the fuel gy (measured in calories) as do nonworking hors- often in ; most epiphysitis problems were of amino acids and minerals as well as trace min- supply available in the muscles of a horse and the es. You must ensure that the racehorses’ diet pro- observed in weanlings; and osteochondrosis erals and vitamins. Such a feed almost always horse’s ability to use that fuel may be altered by vides enough energy to complete the assigned appeared to be most prevalent in yearlings. eliminates the need for any supplements because including different ingredients in the diet and by work (Table 2). the nutrient mix is balanced. using appropriate feeding management and train- A significant challenge in feeding a racehorse Recommendations for weanlings Conversely, a diet of straight and either ing regimens. is to achieve and maintain ideal body condition or grass is unsuitable because it: To achieve high performance, racehorses in The study uncovered one common feeding ◗ Fails to provide the requirement for absorbable for training and racing while providing enough practice that is detrimental to weanlings: Farms lysine.6 TABLE 2. are failing to provide the high ratio of concentrate ◗ Provides less than desirable amounts or ratios to hay needed to meet the weanlings’ require- Approximate daily nutrient requirements of race-bred prospects and racehorses in training (1,100 pounds mature weight). of minerals.5, 16 ments in a reasonable amount of daily feed. In ◗ Often jeopardizes skeletal development. fact, 90 percent of the farms are trying to grow Digestible Crude Lysine Calcium Phosphorus Furthermore, overfeeding hay and feeding weanlings by feeding more hay than concentrate. Energy Protein A unbalanced concentrates will combine to give Furthermore, 22 to 44 percent of these young (Mcals) (pounds) (grams) (grams) (grams) (grams) (IU) foals a “pot-bellied” appearance. Oats can be used horses are receiving a total daily diet that is either as the primary source if they are fortified deficient in amino acids or unbalanced in its min- with a good source as well as the RACE-BRED eral concentration or mineral ratios. In short, mineral concentrations needed to provide the PROSPECTS weanlings and yearlings are being fed almost proper calcium:phosphorus ratio and to meet the identical rations. The feeding programs for year- needs for trace minerals. Although most commer- lings are much more in line with National cial feeds contain some oats, other are also Weaning 15.0 1.7 32 29 16 4.0 10,000 Research Council (NRC)16 recommendations than used routinely. (moderate growth) those for weanlings (Table 1).

Weaning 17.2 1.9 36 36 20 4.3 10,000 TABLE 1. Recommendations for yearlings (rapid growth) Diet proportions for race-bred prospects of varying ages. If not being conditioned for sale, yearlings can Age/Class % Concentrate % Hay achieve a moderate rate of growth on good-quali- 18.9 1.9 36 29 16 5.5 15,000 ty, improved . The digestive tract of a (moderate growth) Weanling 70 30 yearling can process more roughage than that of a weanling. Good-quality appears to sup- Yearling 60 40 port acceptable growth and development at this Yearling 21.3 2.1 40 34 20 5.7 15,000 stage.7 (rapid growth) Long-yearling 60 40 However, yearlings being prepared for sale or (in training) being retained for placement into pre-race training have significantly different nutrient requirements RACEHORSES Two-year-old 55 45 when rapid growth and/or forced exercise IN TRAINING (in training) becomes part of the management scheme. For 16 these horses, you must provide a balanced con- Source: National Research Council (1989) Long 26.5 2.6 50 49* 27* 15.5* 18,000 centrate. To develop properly, race-bred weanlings must These horses typically need to be fed a con- yearling be given a concentrate feed that provides at least centrate with at least 14 percent crude protein, 0.7 percent lysine, which is the primary growth- 0.6 percent lysine, 0.6 percent calcium and 0.4 Two-year-old 26.5 2.5 45 46* 26* 17.6* 20,000 limiting amino acid.16 They also need at least 0.7 percent phosphorus in a feed that contains 7 per- percent calcium and 0.5 percent phosphorus in cent or more fiber and not more than 1.4 Mature-intense 32.8 2.9 45 40 29 15.1 22,000 feeds containing no more than 1.4 megacalories megacalories of digestible energy per pound. work of digestible energy per pound. Many companies manufacture horse feeds that Feeds with higher levels of energy need even meet or exceed these minimums. Source: National Research Council (1989) *Based on recent work of Nielsen et al,13 Stephens et al22 and Nolan et al.15 2 3 fuel to support performance at an intense level of very high energy requirements; they often have Note: To achieve maximum performance in TABLE 3. work. Therefore, a primary concern is energy, trouble getting enough energy from conventional racehorses, feed them a -supplemented, high- Relationship of crude fiber to expected digestible which allows the horse to maintain optimum diets of hay and other fibrous feedstuffs. They diet…not a high-fat, high-fiber diet. energy in conventional and fat supplemented body condition while performing at a heavy work- must be fed grain-based concentrates. They also When feeding a fat-supplemented diet, consid- grain mixes. load. need a comparatively large amount of highly er several factors: To determine the types of diets to feed and the digestible in the diet to meet both aerobic ◗ Horses need time to become adapted to fat in DIGESTIBLE ENERGY (MEGACALORIES PER POUND) energy substrates ( and fatty acids) and, particularly, anaerobic energy demands. the diet, sometimes as much as 4 weeks. Concentrate diet Fat-supplemented diet to make available, you need to understand the Most stables are very accustomed to using ◗ Because a fat-supplemented diet provides more Fiber % (3-4% fat) (7-8% fat) extent to which a horse depends on its system of concentrates to supply soluble carbohydrates for energy, you should decrease the total daily feed anaerobic energy metabolism. During regular energy. Cereal grains such as oats, and intake if the work level and body condition are 2 1.62 1.72 training and racing, a racehorse must perform corn can be mixed together in a variety of ways to to remain the same. both aerobic and anaerobic work. produce concentrates of differing energy concen- ◗ If you plan to top-dress fat or vegetable oil on 4 1.55 1.65 Aerobic work occurs trations. Cereal grains the feed, begin with a small amount and during exercise in which should be processed to increase it gradually, keeping an eye on eating 6 1.45 1.55 the heart rate does not promote digestion of behavior and general well-being. You must exceed about 150 beats starch in the small reassess the total dietary nutrient balance (see 8 1.35 1.45 per minute. While per- intestine and to ensure section on protein), especially for race-bred 10 1.25 1.35 forming aerobic work, a that high amounts of yearlings and 2-year-olds receiving exercise. horse is able to get are absorbed. Remember: The energy requirements for work 12 1.15 1.25 enough oxygen to the Grain feeds provide car- take precedence over the storage of energy as fat tissues to burn fat as a bohydrates that can be in the body. Animals that are not fed enough At any given level of crude fiber, a grain mix fuel source. used directly or stored energy to maintain body weight will use the ener- with 5 percent supplemental fat will have up to 8 During anaerobic in the muscles and gy stored in body tissues — including muscle percent more energy than a similar feed with no work (heart rate is typi- in the form of glycogen glycogen stores — to meet the energy require- supplemental fat. This supplemental fat affects cally above 200 beats for later use. ments for work. A thin horse may not be physio- the relationship between crude fiber and expected per minute), the horse is By manipulating the logically able to exercise strenuously because it digestible energy content by about 0.10 megacalo- unable to rely totally diet and exercise regi- does not have enough available energy. ries or 100 kilocalories per pound of feed. Of iden- on fat for use as fuel. men of exercising hors- To maintain reasonable amounts of body fat tical amounts of two concentrates — one with For this work, it must es, you can dramatically in horses in race training and being worked hard, supplemental fat and one without — the you with rely primarily on Race prospects must be fed balanced increase the concentra- you must increase the energy density in the diet the supplemental fat will contain significantly glucose, and concentrate in two or more feedings daily. tion of glycogen stored in and adjust the amounts of feed proportionally. For more energy, meaning that you can feed less on a liver and muscle the muscles.23 Horses thin horses that are exercising, adding fat to the daily basis. glycogen, which are produced from dietary carbo- deplete their muscle glycogen stores and become diet results in higher muscle glycogen concentra- To be able to meet the nutritional needs of hydrates. In a race, a horse performs mostly unable to work at a high level when they are fed tions than in horses fed conventional diets.9, 20 racehorses, you need not only to know the anaerobic work using carbohydrates, but a combi- too few carbohydrates and put into high levels of Feeding some fat to racehorses helps protect them amount of energy in a feed, but also to recognize nation of carbohydrates and fatty acids in the diet training. But their work performance can be from fatigue even when their body condition is the caloric needs for training and racing. Horses can help a horse work harder and delay fatigue. improved by feeding them high-energy diets with reduced. that are calorie-deficient cannot run at the same To meet the short-duration, high-speed energy an adequate supply of carbohydrates. When selecting a commercial feed, check the intensity as those with enough energy in the diet demands of anaerobic work, it is critical that race- Many studies have shown that adding fat to amounts of fat and fiber listed on the feed tags. and stored in the muscles. horses receive enough readily available energy the diets of horses in race training can improve The information will help estimate the energy When a horse’s body weight is reduced signif- from dietary carbohydrates to maintain blood glu- their muscle glycogen storage and work perform- density of the grain mix. There is an inverse rela- icantly, it often depletes its body energy reserves cose and store energy in the form of muscle ance.12, 17, 20, 26 Fat provides a concentrated supply of tionship between fiber and the expected digestible so that it has too few calories to perform at a high glycogen.12, 17, 18, 20, 25 During anaerobic exercise and energy in an amount of feed that can be con- energy content (Table 3); knowing this can help level for an entire race, regardless of the length of competition, these are primary fuel sources for sumed safely by the horses. You can incorporate you choose concentrates that are a better buy per that race. The goal should be to achieve sufficient horses. fat or oil into a grain mix and increase it to 10 unit of energy. body condition in the horses to maintain muscle Energy must be provided to racehorses in a percent of the concentrate without negatively Lower fiber feeds usually contain more energy glycogen reserves, but not so much as to cause reasonable amount of daily feed that they can affecting dry matter or fiber digestibility. than higher fiber feeds. If you feed good-quality thermal stress.20 consume safely. Depending on the level of activity Although the amount of energy supplied daily hay, there is no need to spend more money on Although racehorses must have adequate body and the energy concentration of the diet, a horse is important, it is equally important that signifi- additional fiber in a bagged horse feed. condition to do their job, excess body fat causes will take in and concentrate in amounts cant amounts of that energy be supplied in a form Some commercial feed manufacturers produce thermal (heat) stress on the horse. Regardless of ranging from 2.0 to 3.0 percent of its body weight that promotes synthesis and storage of muscle fat-supplemented diets. If a feed tag lists a fat body condition, feeding a fat-supplemented diet daily. glycogen in horses that are expected to do short- concentration of 8 percent, in most cases about 4 reduces the thermal stress on horses.18, 21 Thus, it Racehorses performing at intense levels have term, high-velocity, anaerobic work. to 5 percent additional fat has been included. is important that you maintain the horses in lean

4 5 condition but not “ribby.”21 Feed them a fat-sup- what more nitrogen, but not much more. This vitamin is usually supplemented in com- tion known as “track sour.” This condition is plemented diet with adequate carbohydrates and For mature racehorses receiving average-quali- mercial horse feeds at no more than 10 percent of characterized by a dullness in attitude, general other nutrients. With proper training, the horse’s ty grass hay (7 to 8 percent crude protein), the concentration of vitamin A. Excessive vitamin unthriftiness and slowed performance. Loss of performances are likely to improve, with fewer enough additional protein is provided if they are D can cause calcification of soft tissues. appetite is one symptom of a thiamin deficiency. injuries and less fatigue. fed a 12 percent crude protein grain or concentrate Vitamin E: Vitamin E has received increased Although enough thiamin can be synthesized mix. However, a higher percentage of crude pro- attention for its possible role in reducing tissue in the gut to meet the needs of most mature hors- Protein tein may be warranted in two situations: when damage and as an antioxidant. Most feed manu- es, it may not be adequate for racehorses in train- hay quality is suspect, and when supplemental fat facturers already provide supplemental vitamin E ing. Thiamin is part of an system invol- While some attention to protein is important, is being top-dressed onto the concentrate. Al- (Tables 4, 5 and 6). If it is not added to the com- ved in energy metabolism in horses. Therefore, it generally should not be the most critical consid- though adding fat or oils increases the energy den- mercial diet of racehorses, vitamin E will need to racehorses requiring high levels of energy could eration for racehorses. Stables sometimes overfeed sity concentration in the feed, it dilutes the pro- be supplemented to provide at least 45 IU per become thiamin deficient if they take in too little protein because of the misconception that the per- tein. If fat is added at 5 to 10 percent of the grain pound of feed. thiamin in the diet. Diets of only oats and grass centage of crude protein in the grain or concen- mix, the concentrate should contain about 14 per- : Because Vitamin K is synthesized hay may lack the amount of thiamin needed to trate mix must be raised as a horse’s level of cent crude protein. This is especially important for and ab-sorbed in a horse’s , there is meet a horse’s requirements. activity increases. 2-year-old racehorses that are still growing. no dietary requirement In many reported Horses do require a small increase in protein It is useless to feed high-protein feeds to for it. Adequate cases of “track sour” in the diet for optimum production and work per- mature racehorses. Giving a horse more protein amounts of this vita- horses, adding brewer’s 4 formance. But having a high concentration of than it requires creates metabolic stress on the min are produced by yeast to the diet appears protein in a mature racehorse’s diet can do more horse and is an unnecessary expense for the rac- anaerobic bacteria of to stimulate the appetite harm than good. For racehorses in training, it is ing facility. the hindgut. and return the horse to a important to have a balance of amino acids in the Although vitamin K spirited, energetic attitude diet. To receive the proper supply of these amino Vitamins has been added to the with improved work per- acids, they need a source of high-quality protein diets of performance formance. One of the in the regular diet. Vitamin needs are not as well defined in hors- horses to treat or pre- largest components of Although the effects of exercise on the amino es as in other species. Nevertheless, vitamin sup- vent exercise-induced brewer’s yeast is thiamin, acid needs of an equine athlete are not complete- plementation is of great interest to many racehorse pulmonary hemorrhage among other B-vitamins. ly understood, stables should consider protein owners, to the extent that vitamins are often (bleeders), its influ- Heavily worked horses 5 intake in relation to energy intake. A properly bal- grossly overfed in the . ence on “bleeding” receiving traditional anced diet will provide enough protein at increas- Excess vitamin supplementation does not has yet to be docu- diets benefit from hav- ing levels of work, provided that the horse’s ener- improve performance and, in fact, may be toxic mented by equine ing thiamin added to gy requirement is being met through additional and dangerous. If a horse’s diet is well balanced research. Racehorses can utilize calories from a combination the diet.25 If the com- feed intake (Table 2). and contains enough vitamins to meet its needs, B-vitamins: Of of carbohydrate and fat sources to better perform mercial feed has not In studying the nutritional effects of increased over-supplementation of vitamins will not all nutrients used anaerobic work with delayed onset of fatigue. been supplemented with exercise on horses, researchers have found that enhance its physiological performance in training in the horse indus- thiamin, stables should when fed a diet that has a constant calorie:protein or in a race. try, B-vitamins are the least understood yet most include a good supplement containing the B-vita- ratio, horses retain more nitrogen during the con- Vitamin A: Horses obtain significant amounts widely used, if not abused. Like vitamin K, the B- mins, particularly thiamin, in the diet of racing ditioning period than at rest. After conditioning is of the fat-soluble vitamins A, D, E and K from top- vitamins are synthesized in and absorbed from horses. However, there is no benefit in over-sup- achieved and the work level reduced, the horses quality fresh hays. In an athlete, vitamin A helps the large intestine. Stables often incorporate B- plementing B-vitamins. still retain more nitrogen than when not working. maintain normal eating behavior and respiratory vitamins into feeding programs to promote “blood Another B-vitamin, biotin, is often added to Exercising horses in a high state of condition health. However, excessive vitamin A may eventu- building.” However, excesses of -soluble enhance hoof growth or strength. Limited clinical retain more nitrogen than sedentary horses, but ally contribute to bone weakness. vitamins such as B12 are quickly voided in the reports have claimed some improvement in about the additional nitrogen usage is comparatively Reputable feed manufacturers balance concen- urine and do not increase packed cell volume or one-third of horses receiving biotin supplements.2 8 small. Although it is unclear whether they use trate rations by supplementing vitamin A, often in hemoglobin concentration. Instead of over-supple- More recent research has demonstrated that d- the retained nitrogen for muscle synthesis or it is a vitamin premix. Race stables mixing their own menting these B-vitamins, you should rely more biotin supplementation reduces the incidence and lost in sweat, exercising horses do require some feed should usually add vitamin A at about 1,500 heavily on conditioning and exercise to improve severity of hoof wall defects, increases hoof wall small increase in protein, particularly during con- to 2,000 international units (IUs) per pound of blood volume and oxygen-carrying capacity. integrity and reduces the incidence of white line 4 ditioning. feed (see tables 4, 5 and 6 as examples). Some B-vitamins affect equine performance syndrome.10 Changes in muscle composition have been Vitamin D: Dietary requirements for dietary and may need to be added to a horse’s diet if con- Note: In most cases, it takes from 9 months to measured in conditioned horses fed varying vitamin D in horses have not been identified. ditions warrant. Research indicates that exercising more than a year for the benefits of biotin supple- amounts of protein.3 The study found that condi- Horses that receive normal exposure to sunlight horses may need supplemental vitamin B1 (thi- mentation to become observable. Although more tioning changes the diameter of certain muscle and that are fed sun-cured hay will have enough amin) beyond what they would normally synthe- research is needed before exact recommendations fibers and helps the muscles synthesize protein. vitamin D for calcium homeostasis and mineral size in the intestine.25 Horses at the race track can be made about supplementing the diets of Also, horses fed higher protein diets retain some- absorption. sometimes develop a lethargic, depressed condi- horses with poor hooves, providing horses about

6 7 TABLE 4. trate mix and supplemental . However, com- exercising horses, which may be twice the main- Example of a traditional ration for a mature racehorse (designed to be fed with a mix of mercially prepared horse feeds do not normally tenance requirement, particularly if are good quality grass hay and alfalfa hay). Note: This feed contains no supplemental fat. contain enough for horses that sweat not of top quality. The requirement for a lot, particularly in the summer. To compensate heavily exercised horses is about 1.2 percent of for the loss of these electrolytes in the sweat, the total diet.28 Ingredients Percent Pounds/Ton Calculated analysis Important: See Table 7 on expected diets must be supplemented with , chlo- 28 feed consumption, and ride and sometimes potassium. Even if a com- Feeding management Cracked corn 45.00 900 always introduce new mercial feed contains , horses that work hard To achieve the highest level of performance Crude protein = 12.0% grain feeds gradually. and sweat profusely will still need about 3 ounces Whole oats 42.50 850 with a minimum of digestive disturbances, it is Digestible energy = 1.39 Mcal/lb Because this ration (90 grams) of supplemental salt per day in addi- important that feeding is managed well and that contains about 6 percent tion to the salt already in the feed. meal 7.50 150 Crude fiber = 6.0% rations are balanced. Horses must receive the more energy than Few studies have been conducted on the use proper amounts and ratios of nutrients and be fed Crude fat = 3.7% straight oats, smaller of orally drenched electrolytes. The value of this 3.25 65 at regular intervals. Calcium = 0.36% amounts of this ration practice is questionable. Also, there is a chance It makes no difference whether a race stable Calcium carbonate 0.75 15 will usually maintain that adding electrolytes to the drinking water Phosphorus = 0.32% chooses to balance rations by buying formulated, similar body condition. could cause a horse to drink less water, which TM salt 0.75 20 Thiamin = 2.18 mg/lb. could result in dehydration. The most effective finished feed or by buying the ingredients and Vitamin A added at 2,000 IU/lb + Percentages and way to meet the needs of horses is to mixing them. The critical point is to provide Vitamin A + + enough nutrients to racehorses to meet their daily Vitamin E added at 60 IU/lb weights of vitamins A select roughage and concentrates that have a good and E will vary, depend- balance of all the minerals required and to feed requirements and to maintain the ideal body con- Vitamin E + + ing on the vitamin them in adequate amounts to meet the animals’ dition for racing. Either approach will work if premix used. energy requirements. Horses that sweat excessive- careful attention is given in the formulation ly will need additional salt, a total of about 1 per- process. Excessive amounts of nutrients must not cent of the horse’s daily ration. Also, give specific be fed because it results in nutritional imbalance 15 milligrams of biotin a day or about 1.5 parts the combination of growth and exercise. attention to meeting the potassium requirement of and metabolic stress on the horse. per million in the diet appears to help. Young horses in race training are building bone as a part of growth, and they are modeling TABLE 5. Minerals and remodeling bone in response to exercise. Example of a fat-supplemented ration for long yearlings and 2-year-olds in training During the initial stages of training, the calcium (to be fed with a mix of grass and alfalfa hay). As high-performance athletes, racehorses and phosphorus needs of juvenile horses in train- require a balanced supply of minerals for mainte- ing appear to be increased by 30 to 35 percent, nance of skeletal tissue, muscle contraction and and magnesium requirements increased by 80 to Calculated analysis Ingredients Percent Pounds/Ton energy transfer. It is much more critical for stables 100 percent, over current NRC (1989)16 recommen- to ensure that the horses have enough minerals Important: dations. These increases in mineral requirements Cracked corn 37.50 750 such as calcium and phosphorus, relative to the See Table 7 on expected in early training are caused by the demands of feed consumption and amount of energy they take in, than to be con- 14 bone modeling and remodeling. Whole oats 35.00 700 always introduce new cerned with exact calcium:phosphorus ratios. Thus, during the early stages of training, a 2- However, the total diet of horses being trained Digestible energy = 1.6 Mcal/lb Fat or oil 5.00 100 grain feeds gradually. year-old horse requires about 130 mg/kg/day of This ration contains 15 or raced should always contain at least as much calcium, 70 mg/kg/day of phosphorus and 40 Crude protein = 14.8% Soybean meal 15.00 300 percent more energy calcium as phosphorus. Diets with inverted ratios mg/kg/day of magnesium. Juvenile horses in Lysine = 0.7% (more phosphorus than calcium) can contribute than the ration shown in training require total dietary concentrations of cal- Crude fiber = 6% Molasses 4.00 80 Table 4 and about 25 to weakened bones and subsequent lameness in a cium of 0.60 percent; phosphorus, about 0.35 per- Crude fat = 7.3% percent more energy stressed horse. Because cereal grains contain more cent; and magnesium, 0.2 percent. See tables 4, 5 Calcium carbonate 1.25 25 than straight oats, so phosphorus than calcium, inverted or improper Calcium = 0.62% and 6 for examples of rations with suitable miner- smaller amounts of this ratios often occur in the horse industry. Phosphorus = 0.43% al levels. Dicalcium phosphate 0.25 5 ration will need to be fed Cafeteria-style and free-choice mineral feeding Thiamin = 2.57 mg/lb Electrolytes: During workouts and racing, to maintain similar programs do not meet a horse’s requirements for horses lose significant amounts of electrolytes — Vitamin A added at 2,000 IU/lb Brewer’s yeast 1.25 25 19 body condition. minerals. The only reliable way to achieve min- sodium, chloride and potassium — in the sweat. Vitamin E added at 60 IU/lb eral balance is through accurate ration formula- TM salt 0.75 15 Usually it is not difficult to meet the increased + Percentages and tion. requirements for these minerals in horses receiv- Vitamin A + + weights of vitamins A and Recently, Texas A&M researchers studied the ing intense exercise. The majority of these E will vary, depending on mineral requirements of young horses in race increased requirements can be satisfied by good- Vitamin E + + the vitamin premix used. 13, 15, 22 training. They found that calcium, phospho- quality forage, minerals provided in the concen- rus and magnesium requirements are affected by 8 9 TABLE 6. ❷ Similar feed with the same nutrient com- On more than 55 percent of Texas farms, the Example of a high-fat supplemented ration (to be fed position and physical characteristics, espe- single biggest cost of keeping race-bred prospects with a mix of grass hay and alfalfa hay). cially crude fiber. and racehorses is nutrition.5 Although feeding ❸ If none of those is available, buy good racehorses successfully is a challenge, it can be Important: clean oats as a last resort. done. The primary focus should be on meeting Calculated analysis Ingredients Percent Pounds/Ton See Table 7 on expected For horses that have been in strenuous train- the energy and other nutrient needs in an amount feed consumption and ing during the week with Sundays off, reduce the of feed the horses can eat comfortably. always introduce new Cracked corn 36.25 725 concentrate feed accordingly on the off day. When If a horse’s nutritional requirements are met, grain feeds gradually. combined with some free exercise, this reduction but not exceeded, its performance will be This ration contains 16 Whole oats 32.50 650 can help prevent metabolic disorders caused by improved over those horses that are fed imbal- percent more energy feeding high-concentrate feeds in the absence of anced diets in irregular amounts. Cracked corn = 14.5% Fat or oil 10.00 200 than the ration shown in New research information currently available Table 4 and over 25 per- exercise. Digestible energy = 1.61 Mcal/lb offers new approaches to ration formulation, feed- Soybean meal 15.00 300 cent more energy than Reduce the concentrates to about half the nor- Crude fiber = 5.25% ing management and training regimens for race- straight oats, so smaller mal amount and increase the hay allowances. Molasses 3.25 65 horses. Adjustments in these areas offer the best Crude fat = 12.9% amounts of this ration This practice will help prevent feeding-related opportunity to improve athletic performance, Calcium = 0.47% will need to be fed to muscular problems, azoturia (Monday morning Calcium carbonate 0.75 15 delay fatigue and reduce injuries to the high per- Phosphorus = 0.38% maintain similar body disease) and the feeding-related “tying-up” syn- drome. formance horse. Thiamin = 2.45 mg/lb Dicalcium phosphate 0.25 5 condition. Riders should take adequate time to warm up In the future, stables that use research infor- Vitamin A added at 2,000 IU/lb mation and follow sound management practices Brewers’ yeast 1.25 25 + Percentages and the horses before strenuous work and cool them Vitamin E added at 60 IU/lb weights of vitamins A down after strenuous work. will consistently achieve the highest level of per- TM salt 0.75 15 and E will vary, depend- formance in racehorses. Remember: Indiscrim- ing on the vitamin pre- Summary inate feeding of supplements will not result in top Vitamin A + + mix used. athletic performance. Rather, the focus should be on feeding racehorses correctly. It is complicated, Vitamin E + + Nutrition is one of the most important aspects of overall development and management of hors- but it can be done. es. Feeding horses of economic significance is an everyday responsibility. Tables 4, 5 and 6 show examples of rations around the clock, taking workout sessions into that contain differing sources of energy and are account. ◗ balanced for protein, minerals and vitamins. Daily Do not feed concentrates or hay to racehorses TABLE 7. feed intake typically ranges from 2 to 3 percent of within 3 hours before a workout or race. Expected daily feed consumption by racehorses and prospects in training a horse’s body weight. In some cases, extremely Although you can offer hay after the workout (percent body weight)a. hard-working horses may require feed at 3 per- or race, do not feed concentrates for at least 2 cent of horse body weight; such high levels of a hours after exercise. Offer water free choice Feed consumption daily feed must always be provided in two or after exercise, but make sure that the horses by individual horses more feedings per day. AGE OF HORSE OR LEVEL OF WORK drink slowly, initially, after a workout. may vary further In general, concentrate intake should not ◗ If the normal feeding time is delayed, reduce Type of diet according to the exceed 0.75 percent of body weight per feeding, the concentrate portion of the next ration at the Long yearling Two-year-old level of activity and and time intervals between feedings must be the late feeding, then resume the normal amounts In training In training Racing energy density same. If horses can be maintained with concen- of feed at the next feeding. If feeding is delayed of the feeds being trate intakes of 1.5 percent of body weight daily for several hours after a very strenuous work- Typical nonfat diet fed. or less, they can be fed twice daily at 12-hour out or because of transport, feed the horse only intervals. If they require more feed, they should hay at the next feeding and then offer the nor- Concentrate 1.00 – 1.5 1.0 – 1.5 1.50 – 1.75 be fed three times daily, at 8-hour intervals. mal concentrate allotments at the next regular It is sometimes difficult to maintain appetite scheduled feeding. Do not feed any extra con- Hay 1.00 – 1.5 1.0 – 1.5 0.75 – 1.00 and normal feeding regularity in horses that are in centrate to compensate for feed missed because race training or at the track. For these horses, it of travel or other interruption in normal man- 10% fat supplemented diet helps to follow these recommendations: agement. ◗ Use only the highest quality feeds with very ◗ If a racehorse stable runs out of feed, buy feed Concentrate 0.5 – 1.00 0.75 – 1.0 1.25 – 1.5 high energy density, and try to feed the horses in the following priority order: Hay 1.0 – 1.5 1.00 – 1.5 0.75 – 1.00 three times a day at regularly spaced intervals ❶ The same feed if possible.

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1. Anderson, C., G. D. Potter, J. L. Kreider and C. C. 15. Nolan, M. M., G. D. Potter, K. J. Mathiason, P. G. Gibbs, Courtney. 1983. Digestible energy requirements for exercising E. L. Morris, L. W. Greene and D. Topliff. 2001. Bone density in horses. Journal of Animal Science. 56:91. the juvenile racehorse fed differing levels of minerals. Pro- ceedings, 17th Equine Nutrition Physiology Symposium. p. 33. 2. Comben, N., R. J. Clark and D. J. B Sutherland. 1984. Clinical observations on the response of equine hoof defects to 16. NRC, 1989. “Nutrient Requirements of Horses.” dietary supplementation with biotin. Veterinary Record. 115:642. National Academy of Sciences. Washington, D. C.

3. Freeman, D. W., G. D. Potter, G. T. Schelling and J. L. 17. Oldham, S. L., G. D. Potter, J. W. Evans, S. B. Smith, Kreider. 1985. Nitrogen metabolism in the mature physically con- T. S. Taylor and W. S. Barnes. 1990. Storage and mobilization of ditioned horse. II. Response to varying nitrogen intake. muscle glycogen in exercising horses fed a fat-supplemented diet. Proceedings, 5th Equine Nutrition Physiology Symposium. p. 236. Journal of Equine Veterinary Science. 10(5):1-5.

4. Freeman, D. W., G. D. Potter, G. T. Schelling and J. L. 18. Potter, G. D., S. P. Webb, J. W. Evans and G. W. Webb. Kreider. 1988. Nitrogen metabolism in mature horses at varying 1990. Digestible energy requirements for work and maintenance levels of work. Journal of Animal Science. 66:407. of horses fed conventional and fat-supplemented diets. Journal of Equine Veterinary Science. 10(3):214-218. 5. Gibbs, P. G. and N. D. Cohen. 2001. Early management of race bred weanlings and yearlings on farms. Journal of Equine 19. Schryver, H. G. et al. 1978. Voluntary intake of calcium Veterinary Science. Vol. 21, No. 6. p. 279-283. by horses and fed a calcium deficient diet. Journal of Equine Medical Surgery. 2:337-340. 6. Gibbs, P. G. and G. D. Potter. 2002. Concepts in protein digestion and amino acid requirements of young horses. 20. Scott, B. D., G. D. Potter, L. W. Greene, P. S. Hargis and Professional Animal Scientist. J. G. Anderson. 1992. Efficacy of a fat-supplemented diet on mus- cle glycogen concentrations in exercising. Thoroughbred horses 7. Hansen, K. D., F. M. Rouquette, G. W. Webb, G. D. Potter maintained in varying body conditions. Journal of Equine and M. J. Florence. 1987. Performance of yearling horses on pas- Veterinary Science. 12(2):105-109. ture and supplemental feed. Proceedings, 10th Equine Nutrition Physiology Society. Ft. Collins, CO. p. 25-30. 21. Scott, B. D., G. D. Potter, L. W. Greene, M. M. Vogelsang and J. G. Anderson. 1993. Efficacy of a fat-supplemented diet to 8. Hinkle, D. K., G. D. Potter, J. L. Kreider and G. T. reduce thermal stress in exercising thoroughbred horses. Proceed- Schelling. 1981. Nitrogen balance in exercising mature horse fed ings, 13th Equine Nutrition Physiology Symposium. p. 66. varying levels of protein. Proceedings, 7th Equine Nutrition Physiology Symposium. p. 91. 22. Stephens, T. L., G. D. Potter, K. J. Mathiason, P. G. Gibbs, E. L. Morris, L. W. Greene and D. Topliff. 2001. Mineral 9. Jones, D. L, G. D. Potter, L. W. Greene and T. W. Odom. balance in juvenile horses in race training. Proceedings, 17th 1991. Muscle glycogen concentrations in exercised miniature Equine Nutrition Physiology Symposium. p. 26. horses at various body conditions and fed a control or fat-supple- mented diet. Journal of Equine Veterinary Science. 12(5):287. 23. Topliff, D. R., G. D. Potter, T. R. Dutson, J. L. Kreider and G. T. Jessup. 1983. Diet manipulation and muscle glycogen 10. Linden, J., H. Josseck, W. Zenker, H. Geyer and in the equine. Proceedings, 8th Equine Nutrition Physiology J. Schulze. 1993. The effect of d-biotin supplementation on hoof Symposium. p. 119. condition in Lipizzaner horses. Proceedings, 13th Equine Nutrition Physiology Symposium. p. 58-61. 24. Topliff, D. R., G. D. Potter and J. L. Kreider. 1983. Exercise physiology in horses – fitness vs. fatness. Proceedings, 11. Meyer, H. 1987. Nutrition of the equine athlete. In Texas A&M University Horse Short Course. p. 1. Equine Exercise Physiology 2. ICEEP Publications, Davis, CA. p. 644. 25. Topliff, D. R., G. D. Potter, J. L. Kreider, G. T. Jessup and J. G. Anderson. 1981. Thiamin supplementation for exercis- 12. Meyers, H. C., G. D. Potter, J. W. Evans, S. B. Smith, ing horses. Proceedings, 7th Equine Nutrition Physiology T. S. Taylor and W. S. Barnes. 1990. Physiologic and metabolic Symposium. p. 167. response of exercising horses to added dietary fat. Proceedings, 19th Equine Nutrition Physiology Symposium. p. 107. 26. Webb, S. P., G. D. Potter and J. W. Evans. 1987. Physiologic and metabolic response of race and cutting horses to 13. Neilsen, B. D., G. D. Potter, L. W. Greene, E. L. Morris, added dietary fat. Proceedings, 10th Equine Nutrition Physiology M. Murray-Gerzik, W. B. Smith and M. T. Martin. 1998. Symposium. p. 115. Response of young horses in training to varying concentrations of dietary calcium and phosphorous. Journal of Equine Veterinary 27. Webb, S. P., G. D. Potter, J. W. Evans and G. W. Webb. Science. 18(6):397-404. 1990. Influence of body fat content on digestible energy require- ments of exercising horses in temperate and hot environments. 14. Nielsen, B. D., G. D. Potter, E. L. Morris, T. W. Odom, Journal of Equine Veterinary Science. 10(2):116-120. D. M. Senor, J. A. Reynolds, W. B. Smith and M. T. Martin. 1997. Changes in the third metacarpal bone and frequency of bone 28. Hoyt, J. K, G. D. Potter, L. W. Greene and J. W. Evans. injuries in young Quarter Horses during race training observa- 1989. Mineral balance in resting and exercised miniature horses. tions and theoretical considerations. Journal of Equine Veterinary Journal of Equine Veterinary Science. 15(7):310. Science. 17(10):541-549.

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