Horse Feeding and Nutrition

By Tony J. Cunha

This is the second edition of Horse Feeding and Nutrition which was originally published in 1980. It provides the latest information available for those interested in the feeding and nutrition of horses. This new edition has been entirely revised to include the large amount of new research information that has become available since publication of the first edition. Three new chapters have been added, entitled Feeding and Health-Related Problems, The Complexity of Proper Bone Formation, and Exercise Physiology. New feed and food crops, improved methods of production and processing, increased productivity of animals and crops, changes in animal products including more lean and less fat in meat and less fat in milk, longer shelf-life requirements of animal food products, and a myriad of new technological developments have resulted in a need to continually re-evaluate nutrient requirements and supplementation.

Sample diets are given, useful as guides in developing diets for horses. Suggested levels of protein, minerals, and vitamins for use in horse diets are presented. These can be used as guides which can be modified to suit the various feeding situations encountered in horse farms.

The volume of scientific literature is increasing rapidly each year. Moreover, its interpretation is becoming more complex. This increases the need for summarizing and interpreting these new developments in up-to-date books such as in this one.

• Sample diets-useful as guides in developing diets for horses
• Suggested levels of protein, minerals, and vitamins for use in horse diets
• These can be used as guides which can be modified to suit the various feeding situations encountered in horse farms

• Language: English
• Publisher: Academic Press
• Release date: Dec 2, 2012
• ISBN: 9780080917528

Book preview

Cunha

Preface

This is the second edition of Horse Feeding and Nutrition which was originally published in 1980. The book is entirely revised since a great deal of new research information has become available since the book was first written. Three new chapters have been added. They are Chapter 20 on Feeding and Health-Related Problems; Chapter 21 on The Complexity of Proper Bone Formation; and Chapter 22 on Exercise Physiology.

In the first chapter the future of the horse industry is discussed. Chapter 2 reviews the art, science, and myths of feeding horses. Chapter 3 discusses the problems involved in supplying an adequate level of nutrients in horse diets. The digestion of feeds is discussed in Chapter 4. Chapters 5–10 contain concise, up-to-date summaries on vitamins, minerals, protein, amino acids, carbohydrates, fiber, fatty acids, fat, volatile fatty acids, energy, and water. The nutrient requirements of the horse are discussed and compared with National Research Council (NRC) recommendations. Deficiency symptoms of nutrients are discussed. The needs of the horse for various nutrients are presented and give the reader a basis for determining what good, well-balanced diets should contain. The practical application of this basic information is discussed in these chapters and in Chapters 15–18 on feeding horses during various stages of the life cycle.

The important interrelationships between nutrition, disease, and performance are discussed in Chapter 11. The relative value of various feeds for use in horse diets is discussed in Chapter 12. The value of pasture and hay for horses is presented in Chapter 13. Hints on feeding horses for optimal result are discussed in Chapter 14. Chapters 15–18 present information on feeding the foal, growing horse, performance and race horse, and mare and stallion. Chapter 19 discusses purified diets for horses, and Chapter 23 presents information on antibiotics, learning ability, feeding behavior, nutrient toxicity, weight equivalents, weight-unit conversion factors, and the effect of cold weather on horses. Sample diets are given, useful as guides in developing diets for horses. Suggested levels of protein, minerals, and vitamins for use in horse diets are presented. These can be used as guides which can be modified to suit the various feeding situations encountered on horse farms.

This book provides information helpful to those interested in the feeding and nutrition of horses. It is written in a manner designed to be especially valuable to beginners in horse production, established horse owners, and those who are concerned, directly or indirectly, with horse feeding and nutrition. This book will be very helpful to feed manufacturers and dealers and others concerned with producing the many different nutrients, supplements, feeds, and other ingredients used in horse diets. It will also be of value to county agents, farm advisors, consultants, veterinarians, and college and university students and teachers of courses on feeds and feeding, horse production, horse nutrition, and animal nutrition. The text contains basic information for students on these and other courses. It contains many key references for those interested in obtaining further information on a particular subject.

In preparing this book I have had the benefit of suggestions from many eminent scientists in the United States and abroad. Moreover, they supplied me with various publications and photographs for use in this text. I especially want to thank the following who provided the most assistance: Norman K. Dunn, Gerald E. Hackett, and Steven Wickler, California State Polytechnic University, Pomona; Larry M. Slade and James L. Shupe, Utah State University; E. A. Ott, S. Lieb, L. R. McDowell, J. H. Conrad, R. L. Asquith, and D. C. Sharp, University of Florida; G. D. Potter, D. D. Householder, J. L. Kreider, C. H. Bridges, and J. W. Evans, Texas A & M University; H. F. Hintz and H. F. Schryver, Cornell University; Tom N. Meacham and J. P. Fontenot, VP1; R. M. Jordon, University of Minnesota; R. R. Johnson, California State Polytechnic University, San Luis Obispo; J. P. Baker and S. G. Jackson, University of Kentucky; C. G. Depew, Louisiana State University; J. J. Kiser, Iowa State University; M. A. Russell and T. W. Perry, Purdue University; D. R. Topliff and D. W. Freeman, Oklahoma State University; L. M. Lawrence and K. H. Kline, University of Illinois; R. Albaugh, University of California; G. M. Weber, USDA; R. A. Mowrey, Jr., North Carolina State University; M. J. Glade, Northwestern University, N. Comben, England; M. Bradley, University of Missouri; K. Malenowski, Rutgers University; S. Donoghue and S. L. Ralston, University of Pennsylvania.

Tony J. Cunha

1

Horse Industry Future

I. INTRODUCTION

During the last 30 years the horse industry has gone from a minor declining industry to a major and active multibillion dollar industry. During what might be called the horse-power era, from about 1860 until 1915, horses reached a peak of about 27 million head in the U.S. A gradual decline in numbers then occurred as the horse was replaced by the tractor, truck, automobile, and other automation. By 1960, horse numbers had declined to about 3 million head. But, soon thereafter, horse numbers started to increase rapidly as their use for riding, recreation, and sports activities increased (Fig. 1.1).

Fig. 1.1 Youngsters enjoying a ride with horses in Gainesville, Florida area. Horses are an excellent recreational activity for young girls and boys. (Courtesy of T. J. Cunha, University of Florida and Cal Poly University, Pomona.)

Unfortunately, there are no exact figures on the number of horses in the U.S. at the present time. Estimates and surveys vary from 5 to 9 million depending on whose figures one uses. Regardless of the approximate number, the horse industry has developed into a big business and all indications are that it will continue as such (1,2).

II. HORSE INDUSTRY FACTS

The American Horse Council (3) 1987 report presented the following equine industry data in their horse industry directory:

1. Horses contribute approximately $15 billion annually to the economy of the U.S.

2. Horse owners account for about $13 billion in yearly investment and maintenance expenditures.

3. Horse sports draw more than 110 million spectators yearly.

4. U.S. race track attendance exceeds 70 million each year. Wagering on horse races surpasses $13 billion yearly. In Canada, an additional 12 million people attend horse races and wager about $1.6 billion yearly.

5. The U.S. Department of Interior estimates that about 27 million people over age 12 ride horses yearly, with about 54% riding on a regular basis and the remainder for occasional recreation.

6. Horse exports amount to approximately $200 million yearly.

7. Texas and California are the leading horse population states.

8. Breeds with the highest individual population counts are (1) Quarter Horses, (2) Arabian, Anglo-Arab, and Half-Arab, and (3) Thoroughbreds.

9. From 1960 to 1986 yearly registration figures for the major American light horse breeds increased from 70,050 to 306,584 head. These figures indicate the great increase in the number of quality horses that are registered yearly.

The monetary value of all breeds of horses has increased a great deal. As one example, Thoroughbred yearlings in select sales in 1960 averaged about $25,000 compared to $356,000 in 1982 (5).

III. 4-H CLUB HORSE PROJECTS

During 1987, 4-H Club Youth Enrollment in horse and pony organized projects and activities numbered 224,903 (2). This compared to enrollments of 107,417 in swine, 107,376 in beef, 97,939 in sheep, 85,579 in poultry, 70,711 in dairy, and 19,274 in goat 4-H Club projects. These numbers indicate the high degree of interest in the nation’s 4-H Club Youth in horses. It’s interesting that female enrollment in the horse and pony projects was 152,743 as compared to 72,160 males enrolled. These youth enrollment figures are further evidence that the horse industry will continue to be an important industry. In 1966, 4-H Club horse projects took the lead over 4-H Club beef projects.

The top 10 states with 4-H Club youth enrollment in horse and pony projects in 1987 were as follows (2):

It is estimated that about 50% of the new market for horses each year is due to youth programs. Enjoying horses during their leisure time is one of the most wholesome activities young people can engage in. In 1977 it was estimated that 40% of all horse owners were under the age of 20 and approximately 60% of the horse owners were from families with an annual income under $10,000. These figures indicate the importance of youth in the horse industry. Moreover, it indicates that horses are no longer used primarily by wealthy individuals.

IV. HORSE ACTIVITIES AND USE

As the United States has become more affluent, many who previously could not afford a horse, can now have one. Horses are no longer used primarily by wealthy families. Saddle clubs and 4-H Club projects have grown rapidly. This has resulted in a great increase in people of all ages riding for pleasure and recreation. There has been an increase in riding trails along roads and highways, as well as bridle paths in city parks and other areas. Horse academies and other horse establishments have increased in number and are available to teach people to ride and to train horses. Many of them will board horses for those who do not have facilities for their own animals.

Horses are also used for the game of polo, which is expanding. Riding to the hounds is another area where horses are used. About one-half a million horses are used as cow ponies on the range (Fig. 1.2). Horses are also used in rodeos (Fig. 1.3), racing (Fig. 1.4), as pack animals, for trail rides, mounted patrols, parades, movies, T.V., and other activities. The Forest Service uses horses in some areas. In the laboratory the horse is used to produce certain medicines for human use. So the horse industry has established a definite and important role throughout all segments of U.S. society.

Fig. 1.2 Horses are used for working cattle in a Florida ranch. They can be used in areas where jeeps or trucks cannot go. (Courtesy of T. J. Cunha, University of Florida and Cal Poly University, Pomona.)

Fig. 1.3 Scene at Silver Spurs Rodeo in Kissimmee, Florida. Rodeos are a prominent activity and enjoyed by many. (Courtesy of T. J. Cunha, University of Florida and Cal Poly University, Pomona.)

Fig. 1.4 Horses are used for racing which is the leading spectator sport in attendance in the United States (Courtesy of T. J. Cunha, Cal Poly University, Pomona.)

V. HORSE CONTRIBUTIONS TO THE PUBLIC

1. Since the early 1930s, horse racing has been America’s number one spectator sport. In 1981, horse sports generated $1 billion in revenue from taxes on legalized betting, for federal, state, and local governments (4). In some states this revenue is an important part of their budget. In Florida, for example, where the revenue is divided equally among all its counties, the revenue is a very important part of the budget of the small counties. Without that revenue, many of them would have financial difficulties.

Horse racing, therefore, is an important recreational industry (5,6,7). Moreover, it provides an important revenue source. It is hoped that some of this revenue might be diverted to horse programs in the states where it is generated. For example, in New York, 2% of the revenue is used to support equine research at Cornell University (8). Proper action by the horse industry and state legislature can make this happen elsewhere.

2. People in all walks of life and at all ages like to ride horses for pleasure, recreation, and exercise. Riding is one of the best forms of exercise and is prescribed by many in the medical profession. All organs of the body are exercised by riding.

3. Riding horses for pleasure, work, and recreation saves on energy and helps keep the environment clean since autos, trucks, and other vehicles are not otherwise being used.

4. Horses are used by handicapped people as a source of exercise and for recreation and pleasure. A handicapped person who has the use of his arms can ride (after being helped onto a horse). Some seriously handicapped people ride horses even though they need to be strapped to the horse and the animal is led by a normal rider.

5. Horses provide employment for many industries. It is estimated that from $1000 to $1500 or more is spent on each horse yearly for tack, housing, equipment, feed, health care, and many other items.

6. It is estimated that about one-half million horses are used by U.S. livestock producers on their farms and ranches in working their animals, checking on fences, and doing other chores. They can get to areas the jeep or truck cannot reach. Moreover, they are better adapted to working animals.

VI. RESEARCH AND EDUCATION NEEDS

The science of modern horse production is in its infancy. The technology required for optimum training and performance of the high-level performance horse is likewise just emerging. There is no doubt that less is known about the science and technology of horse production and use than that of other farm animals.

Following are just a few major problems facing the horse industry which indicate the great need for new technology:

1. The average foal crop is 50–60% depending on whose estimate one uses. This means that the majority of mares foal one year and skip the next.

2. It is estimated that only 50% of the thoroughbred horses that start training ever reach the track for racing. Moreover, only 20% of those continue to race throughout the first year. Feet and leg problems are responsible for a large percentage of the drop out. Many of these problems occur because the young horse is pushed to a level of training and performance that is too great and too early, which can result in damage to immature, partially ossified bones, which leads to bone abnormalities.

3. Very little is known about the nutrient requirements of the horse. Even less is known about the nutrient needs of the high-level performance horse. This knowledge is needed to design optimum diets for the specific activity the horse is to be involved in.

4. The field of muscle exercise physiology is in its infancy. As this area is developed, it will provide the knowledge needed to obtain optimum conversion of chemically bound and stored energy into the energy required for optimum muscular contraction and action. The performance of the horse athlete has not improved much over the past 50 years as compared to the human athlete. Unlocking the secrets of muscle exercise physiology will enable the horse to start improving its performance level.

5. The horse developed as an animal that was used to life in the wild. But stall confinement, access to limited grazing and exercise areas, and intensified production methods used with high-level performance horses has brought on many problems which need solving.

6. Disease and parasite problems with horses are very serious and take a heavy toll yearly, which some people estimate decreases production efficiency 15 to 20%. The objective should be to develop adequate prevention programs rather than just treatment.

7. Studies on buildings, equipment, and automation are needed to reduce labor costs, which are exceedingly high in too many operations. Obtaining high-quality labor is a major problem and indicates the need for training programs designed to improve the labor situation.

VII. NEED FOR MORE UNIVERSITY INVOLVEMENT

During the past 20 years there has been a gradual increase in horse research, teaching, and extension programs in the U.S. (Fig. 1.5), but a greater increase still is needed in the future. Some universities that do not have an extensive research and/or teaching program have a horse extension program. Some universities have a good teaching and extension program, but little or no research effort. In the last few years the horse program has been curtailed at a few universities. But, overall there has been an increase in horse programs at U.S. universities which is encouraging.

Fig. 1.5 Universities and colleges are expanding their educational emphasis in the area of horse production. The W. K. Kellogg Arabian Horse Center at Cal Poly University, Pomona, California is one of the finest. (Courtesy of Professor Norman K. Dunn, Cal Poly University, Pomona.)

It is important to note that a number of universities have excellent research, teaching, and extension programs with horses. In a few universities the horse programs are outstanding and on a par with their other livestock programs.

An indication of the increased research effort with horses can be obtained by perusing the 1987 Proceedings of the Tenth Equine Nutrition and Physiology Symposium. There were 100 research reports presented in all areas of horse production. Nine reports were given on teaching and extension work. Moreover, the knowledge presented has been of considerable assistance to the horse and other related industries (Fig. 1.6).

Fig. 1.6 Attractiveness of a farm is an important part of the total merchandising program. This beautiful scene is of the Westerly Stud Farm, Santa Ynez, California. (Courtesy of Professor Norman K. Dunn, Cal Poly University, Pomona.)

The symposium began in 1968 when the Equine Nutrition and Physiology Society was started by a small group of scientists interested in horse production. Each meeting, which occurs biannually, is held at a different university site. The number and quality of papers has increased with each subsequent symposium.

There is no doubt that the symposium has been a major factor in increased horse research, teaching, and extension programs at the university and industry level. In addition to the papers presented at the symposium, other papers are presented in other journals and publications.

These and many other research studies can provide a productive and useful life for the horse. They are also needed to increase the profitability of horse enterprises. Competition is increasing for the recreation and sports dollar. To meet this competition, horse people need to use more scientific information to improve their programs further and thus make them more competitive.

In addition to research, it is important to have a viable teaching program. Students need training in all aspects of the horse industry as well as in related enterprises which supply goods and services for horse people. Without this training, the industry is less able to keep up with enterprises using more sophisticated and up-to-date innovative methods. In addition to undergraduate study, there is a need for graduate training and research in various aspects of the horse industry.

Extension activities are a necessary part of a university program. This includes programs in cooperation with the County Agent or Farm Advisor. It also involves short courses, seminars, field days, clinics, and other activities designed to help the horse and related industries augment their programs.

Teaching, research, and extension programs at universities need to be properly supported and take their rightful place along with other livestock programs. The horse industry is a very important one and needs science and technology to help it survive the future in an increasingly competitive society.

It is important for the horse industries and others involved with them to make their needs known to those in authority to help allocate the needed resources to help them with their problems.

VIII. DRAFT HORSES, MINIATURE HORSES, AND PONIES

A. Draft Horses

Draft horses are still being used in various activities in the U.S. such as logging, heaving-pulling contests, parades, horse shows, circuses, movies, TV, pleasure driving, etc. Many are still being used on small farms. A few religious groups have never abandoned the draft horse on their farms. Most draft horses are found in the north central states and Canada although they are widely distributed in both countries. During recent years there has been an increased interest in the use of draft horses, as evidenced by the number of states that have draft horse organizations.

The first National Research Council (NRC) report in 1949 on the nutrient requirements of the horse gave much more attention to draft horses than light horses but it stated that information on nutrient requirements was very limited (5). Subsequent NRC publications have increasingly involved research information with the light horse breeds since that was the information available. The 1989 NRC report on nutrient requirements of the horse does not have a section on draft or miniature horses, but, with some modification, some of the information presented also has some application to both. Texas A & M studies (9) with purebred Belgian and Percheron horses showed that it takes less feed per unit of body weight to maintain heavy, draft-type horses than lighter horses, an observation that is frequently voiced by draft horse breeders. It is suggested that owners of draft horses, miniature horses, and ponies wanting assistance on diet formulation should visit or call their State Agricultural University and confer with those in charge of the horse program.

B. Miniature Horses

A number of breeders have used small ponies to breed miniature horses. Many are used as pets, in parades, shows, circuses, and other activities. They are in limited supply and the demand is good. They are expensive and sell well. The offspring of some become too large which lessens their demand and sale value.

The American Miniature Horse Association (AMHA) is headquartered in Fort Worth, Texas. It has 2800 registered members with Texas, California, Florida, and Indiana having the most members in the order listed. AMHA members can be found in most states as well as in some foreign countries including England, Japan, and Australia (9,10). To be registered with AMHA, a miniature horse cannot stand taller than 34 inches when measured from the base of the last hairs of the mane to the floor, while the horse is standing squarely. They usually weigh under 300 pounds.

C. Ponies

Ponies are very popular, especially with children. Children given the responsibility to care for a pony develop character and the ability to enjoy an animal and the pleasure it can provide them.

Ponies are used in many research studies on feeding and nutrition. It is easier and less costly to use them in certain studies and the results obtained have application to both the pony and the horse. Much of the information presented in the 1989 NRC publication on nutrient requirements of the horse has application to the pony.

The pony is defined as being under 14 hands, 2 inches by the American Horse Show Association. The small pony is 13 hands and below whereas the large pony ranges from 13 hands to 14 hands, 2 inches. Many pony breed registries define a pony as being under 14 hands.

Ponies are used for pleasure riding by children. Some are used and shown in many events by children and adults. They are used in pony-pulling contests and pony harness racing, with parimutuel betting. They are also used in parades, circuses, movies, TV, and many other events.

IX. CONCLUSIONS

In the last 30 years the horse industry has gone from a minor declining industry to a major one and has an excellent future. Horses contribute approximately $15 billion annually to the U.S. economy. Horse racing is by far the leading spectator sport in the U.S. Horse sports draw more than 110 million spectators yearly. In 1981, horse sports generated $1 billion in revenue for federal, state, and local governments.

In 1987 there were 224,903 4-H Club youth enrolled in horse and pony organized projects and activities which is by far the most popular youth livestock program. It is estimated that 50% of the new market for horses is due to youth programs. The great interest of youth in horse programs speaks well for the future of this industry.

Horses are used for riding, pleasure, recreation, exercise, racing, polo, rodeos, pack animals, parades, movies, TV, mounted patrols, working livestock, and a myriad of other activities. They touch the lives of millions of people.

The horse industry faces many serious production problems which require more university involvement in research, teaching, and extension programs. These programs have been neglected until recent years and as a result less is known about the science and technology of horse production than other farm animals. It is encouraging to note that this situation is being changed and increasing university programs are underway. But, more effort is needed in the future. Horses, ponies, and miniature horses have an excellent future.

REFERENCES

1. Weber, G. M. USDA, Washington, D.C. (personal communication), (1988).

2. USDA. Annual 4-H Youth Development Enrollment Report. USDA, Washington, D.C., (1987).

3. American Horse Council. Horse Industry Directory. AHC, Washington, D. C., (1987).

4. American Horse Council. Horse Industry Directory. AHC, Washington, D. C., (1982).

5. Hintz, H.F., Squires, E.L. J. Anim. Sci.. 1983;57(Suppl. 2):58.

6. Hubbard, D.D. Extension Service. Washington, D. C.: USDA, 1977. (personal communication)

7. Lochhead, C. Insight. 1988;4(51):44.

8. Potter, G. D., J. W. Evans, G. W. Webb, and S. P. Webb. Proc. Equine Nutr. Physiol Symp., 10th 1987 p. 133 (1987).

9. Pryor, A. Calif. Farmer. 1989;270(3):48.

10. Anonymous. The History of the American Miniature Horse. American Miniature Horse Assoc. p. 1, Fort Worth, Texas (1989).

2

Art, Science, and Myths in Feeding Horses

In spite of new developments in horse nutrition, the art and science of feeding are still important in properly feeding a top quality race or high-level performance horse. The science involves knowing the nutritional value of feeds, their limitations, the nutrient requirements of the horse, and the technology of combining this information into well-balanced diets to supply the needed nutrients for the various periods of the horse’s life cycle. The art involves knowing how to put all the new technology together and getting the horses to make use of it.

I. ART OF FEEDING

The art consists of knowing how to feed a horse and properly take care of its needs. Each horse is an individual and has peculiar needs and desires. To a certain extent, horses are like humans and vary considerably in likes and dislikes for certain feeds and levels of feed intake. Some prefer more hay, others dislike one hay or concentrate feed as compared to another, while some will want to eat more frequently. Many horses are prima donnas and require a certain degree of pampering to persuade them to consume their feed. Close observation is necessary to determine peculiarities and individual needs. A good horse feeding program thus depends almost as much on the feeder as it does on the diet being used. A well-balanced diet is a necessity. However, a competent feeder is needed to ensure that the diet does the job it is capable of. There is no substitute for a feeder who has integrity, is dependable, alert, a hard worker, a good observer, a student of horses, and who feeds the horses on a regular schedule. A good diet, therefore, is only the beginning of a good feeding program. The art, as practiced by the good feeder, is uniquely important, especially for top quality horses being developed for racing and performance purposes. A good feeder with a good diet means the difference between developing a champion or just another horse (Fig. 2.1).

Fig. 2.1 To obtain contented horses such as these requires a knowledge of the art and feeding of horses. These are Thoroughbred horses in the Ocala, Florida area. (Courtesy of T. J. Cunha, University of Florida and Cal Poly University, Pomona.)

II. SCIENCE OF FEEDING

The science phase of horse feeding is also very important. It requires a knowledge of feeds, their analyses, their limitations, and how to combine them in a well-balanced diet. Feeds vary considerably in their nutrient content and feeding value, which is often affected by methods of processing and storing. Even though a diet contains the same feed formula, its nutritional value will not always be exactly the same, nor will it give the same results in a feeding program. The grains used, such as corn, oats, barley, and others, and the protein supplements available will vary in protein level as well as other nutrients. Not all the grain and protein supplements (such as soybean meal, cottonseed meal, linseed meal, and others) used during the year will come from the same locality. They will vary depending on where they were produced, stored, processed, and how they were transported. Rolled oats, for example, will vary depending on the feed mill which rolled them and the temperature, moisture, and other conditions involved in the processing. Protein supplements will vary depending on the method of extracting the oil, temperature used, and other factors. In other words, animal feeding is not an exact science. The only thing one is absolutely sure of is that variation in results will occur. However, this variation can be minimized by someone with training and experience in feeds, nutrition, and feeding.

Familiarity with vitamins, minerals, protein, amino acids, fatty acids, carbohydrates, and other nutrients, which are part of a good feed program, is of great importance. Understanding these nutrients, their interrelationships, their level and availability in different feeds, which nutrients need to be added to the diet, and how to accomplish this are areas requiring expertise. One also needs to know the nutrient requirements of the horse during the various stages of its life cycle, including the suckling stage, weanling, yearling, 2 year old, training, gestation, and lactation periods. Diets should be formulated which adequately take care of each stage of the life cycle since the level of nutrients needed in the various diets will vary in order to meet those particular nutritional needs. Development of diets for top quality racing or performance horses requires considerable expertise, especially since only a few of the actual nutritional requirements of the horse have been determined in experimental studies. Extrapolation from experimental work with the pig, cattle, and other animals needs to be done to arrive at tentative nutrient levels for use in horse diets. These tentative levels should be determined by competent nutrition scientists, until such time as more exact information becomes available.

So, in feeding top quality horses, the art and the science have an equally important role. Both are needed and proper attention to the small details involved in each area can mean the difference between developing a champion or just another horse.

III. MYTHS IN FEEDING

More myths surround the feeding of horses than with any other animal. It is partially due to a lack of research information on the feeding and nutrition of horses. Consequently, less is known about their requirements for vitamins, minerals, amino acids, protein, fatty acids, and other nutrients. Horse nutrition is perhaps 15–20 years behind that of other livestock species. As a result, too many horse owners and others are still following folklore, old wives tales, and myths in their feeding programs. The author has worked with many owners or managers in programs to improve the feeding and nutrition of horses. After mutual agreement of the diet to use and the complete feeding program to follow, it was never surprising to occasionally find the person who was actually doing the feeding sprinkling some preparation or special mixture on the diet at feeding time. Their explanation was that the horses would not do well unless they also received these supposed magic potions. They were actually convinced about the absolute necessity for these additions to the diet. Some horse owners who want to develop a champion are not concerned about the extra cost involved. The overriding factor is their search for some trade secret or potion that will change the horse into a winner instead of just another horse. Unfortunately, these magic potions for developing champions are not available. The best route to follow is that of feeding a well-balanced diet along with a good breeding and management program. Horse people not knowledgeable in the feeding and nutrition of horses should seek the advice of those who are. Magic potions or other supposed short cuts to producing a champion may do more harm than good.

3

Problems in Supplying Proper Nutrient Supplementation

I. INTRODUCTION

Diet formulation to ensure a proper level of nutrients is more complex than many realize. This becomes more apparent as one acquires experience and knowledge in feeding and nutrition. It becomes even more apparent as one tries to coordinate university and other research findings with those occurring on horse farms under varying conditions of management, environment, stress, disease level, and feeding programs. Nutritional requirements obtained under carefully controlled research laboratory conditions may need modification to provide adequately for the myriad of factors encountered on farms which can alter nutrient needs. Even a proper evaluation of research findings by various research laboratories in the U.S. and abroad will indicate that variation occurs in specific nutrient recommendations made by various scientists whose conditions of study differed. Thus, it requires experience and good judgment to put all the research information together and come up with nutrient levels to use for specific horse programs in different locations and situations (1).

The National Research Council (NRC) nutrient requirements committee on horses is very helpful in developing nutrient requirement levels. The committee consists of six distinguished scientists who have stature and considerable expertise in horse feeding and nutrition. But, even they have differences of opinion and some of their final suggested nutrient levels may be a committee compromise which takes into account the many factors which may affect nutrient needs as well as the varying results available in the scientific literature throughout the world.

II. NUTRIENT REQUIREMENTS OF THE HORSE

As one acquires experience and expertise in horse nutrition, it becomes apparent that there are no exact nutritional requirements (1). At best, one can only recommend an approximation of nutrient needs. It is also apparent that a nutrient requirement obtained under one set of conditions cannot be used to generalize for all conditions and all localities. The NRC-recommended nutrient requirement levels are still the best guideline available and should be used as a starting point by those formulating diets. In some cases the NRC-recommended nutrient levels may be satisfactory and in others a modification may be needed to properly take care of the many factors which may alter nutrient needs. The following discussion in Sections A to V will involve the many factors which can alter nutrient requirements.

A. Variation in Requirements by Animals

Most nutritional requirements are based on the average performance of a group of horses. But, if one produces a deficiency of a specific nutrient in a group of horses, some will show signs of a deficiency quickly, others will take a longer period of time, and some animals will show very little, if any, symptoms. This indicates a difference in their nutrient needs which may be due to many factors including genetic differences. This also shows that only a certain percentage of the horses will first show deficiency signs. They are the indicator animals and are telling the producer something is wrong and needs attention (1).

One such example, even though it is with the pig, is a study at Michigan State University (2). It showed that a level of 4.15 mg of pantothenic acid per pound of feed was adequate for only 5 of the 10 pigs in the experimental lot. These five pigs gained normally and at no time showed any signs of a deficiency. The other five pigs, however, showed typical pantothenic acid deficiency symptoms. This example is with the pig but the same may also occur with the horse.

Thus, individual animals vary in their requirements of nutrients. This means that some margin of safety is desirable in formulating diets and especially with nutrients that are not very stable and may be slowly and gradually destroyed by long storage.

B. Feed Nutrient Levels Vary

Some of the many factors which affect the level of nutrients in feeds are as follows: soil type and level of fertilization; stage of maturity at harvesting; harvesting methods; processing methods; handling and storage methods; exposure to varying temperature, humidity, and other environmental factors; moisture level; rancidity level; variety of feed; time interval between harvesting, processing, storage, and its use; and many other factors.

These and other factors are responsible for feeds varying considerably in feed composition. The 1982 NRC publication on United States–Canadian Tables of Feed Composition states that Organic constituents (e.g., crude protein, cell wall constituents, ether extract, amino acids) can vary as much as plus or minus 15%, the inorganic constituents as much as plus or minus 30%, and the energy values as much as plus or minus 10% (3). So, feed composition tables are average values which can be used as a guide. But, they need verification with actual analyses of the feeds used by the research scientist and the feed-formulating industry.

C. Variation in Availability of Nutrients in Feeds

There are differences in the availability of nutrients, depending on their form. There is also a difference between the availability of these nutrients as determined by a chemical analysis or a microbiological assay and as determined by the use the horse will make of them. Their use by the horse may be different from the figures published on the nutrient analyses by various assay methods. This does not mean that analytical values are not valuable—they definitely are. It does mean, however, that some degree of reservation should be exercised and that provision should be made for taking care of this possible difference in availability. Just one example of this difference in availability is the Purdue University finding by Dr. W. M. Beeson that zinc in soybean meal protein is less available than that in casein. This is due to the phytic acid in soybean protein forming a complex which makes the zinc less available. A horse-feeding trial is the final criterion for determining whether a certain combination of feeds mixed by a feeder or feed manufacturer is adequate in certain nutrients. As diets vary in their makeup with different feeds, there undoubtedly is some difference in the availability of the nutrients contained therein. This problem requires careful consideration by those concerned with formulating