Equine Science Update

COST EFFECTIVE HORSE MANAGEMENT Dr. A.N. Huff, Virginia Tech Horses are kept for business, sport, hobby and recreation. The values and expenditures will vary according to investment, use and return. Thus, horse owners must continue to evaluate their objective and the resuits or returns economicallyor perhaps even as simply pleasure, physical activity or as an enjoyable sport. Horse businesses should be planned, operated and evaluated on a similar basis as any other business. Probably, most of the high dollar investments are in the business end of the industry. However, most of the horses (and people involved) are in the recreational phase, around eighty percent of all horses fall into this category. We need to promote all aspects of the industry and to expand the user base which will primarily be in the areas of family recreation, youth and public riding and use. One drawback to possibly expanding the user base, which includes millions of non-horse owners, is the cost of buying, maintaining and using the horse. We need to keep more families and youth involved in the industry. Quite simply, in many cases, we have made horse ownership too complicated. Horses are large, athletic animals that do not have to be treated as expensive forms of fragile art. We add to this a tremendous knowledge explosion, research and educational work of which we all are proud, within the past few years. This is important, and should continue but it is the selection and application of technology on a per use and related cost effective basis that we should perhaps now address. We need to develop and publish systems for horse use and ownership. The equine media does a great job but if a new owner tried to apply all of the technology available, the owner would need to lock the horse up in a fine sanitized hospital and monitor the horse on a twenty-four hour basis. This would include support staff, instrumentation, computers and the finest in nutrition and health care. This, of course, is Volume 7, Number 3, 1987

million dollar'high performance horse, the hundred thousand dollar yearling and the average recreational horse do not require the same level of management or technology. Thus, we need to develop systems and to assist all horse owners in making wise decisions about purchase, maintenance, medical care, and use of the horse. This is not to mean that any horse will not receive adequate care, feed, etc. A cost effective system would permit all owners to make proper decisions about horse care and ultimately to enjoy and to stay in the business, for profit and/or fun. We may start at the average recreational owner level. A new owner may purchase a suitable horse at a fair market value. Buying the horse and finding a place to keep it is complicated enough plus equipment, riding lesson, etc., etc. Now he reads or we tell him - watch out for blister beetles, selenium poisoning, grass founder, calcium deficiency, bots, shots for several diseases, poor hay, moldy corn, ticks, insurance, face flies, manure in the pasture etc., etc., etc., etc. No wonder that the industry has some problems in attracting new owners. We can get more people in the industry and keep more of the recreational riders by a sound but simple approach to horse keeping. This would include a pre-purchase examination and a simple management and riding program from a knowledgeable person. A few things the horse does need (not limited): 1. Safe pasture or stall 2. Exercise 3. Grass or hay daily 4. Free choice water (except when hot) 5. Free choice salt 6. Grain as needed only to maintain weight or to do added work 7. Hoof trimming every six weeks 8. Deworming at least four times a year 9. Tetanus shot (yearly) 10. Shelter from sun and bad weather 11. Advice to the owner on an as needed basis from a veterinarian and knowledgeable rider. Most of these owners need older, sound, gentle, bomb proof horses and should not be encouraged to go into the breeding business. From this basic approach, technology may be selected and applied at a higher level per need and value of the horses involved on a cost effective basis.

PROBLEM FOAL The second annual Texas A&M University equine Symposium will be held at Texas A&M University, October 17 and 18. In announcingthe Symposium, Dr. J. Warren Evans, coordinator of the Symposium; stated that "this years Symposium will concentrate on the problem broodmare and the problem foal by presenting the latest concepts and methods of management to increase the reproductive efficiency of the problem broodmare and managing the problem foal." Ginger Hyland, one of the most successful breeders of running Quarter Horses and member of the AQHA Research Committee, will give the keynote address. She will give her views of what will be happening in the breeding business and the common problems encountered while managing broodmares and foals. A review of uterine defense mechanisms and current concepts for treating the infected uterus will be discussed by Dr. A. C. "Woody" Asbury, a leader in research efforts to find more effective ways to treat the problem broodrnare. The events that occur during early pregnancy and their relationship to early embryonic loss will be explained by Dr. Dan Sharp from the University of Florida. Management procedures to detect early embryonic loss and subsequent management of the mare will be presented. He will also discuss the controversial subject of treating mares with progesterone during pregnancy and present methods of treatment that are currently being utilized. Methods of monitoring the plasma progesterone concentration will also be explained. Recent research has revealed that often the difference between success and failure in obtaining a live foal and getting the mare to breed back is related to her nutrition program. This topic will be presented by Dr. Gary Potter of Texas A&M who serves as a member of the National Research Council's committee on equine nutrition. Dr. Dickson Vamer will discuss procedures for a reproductive soundness evaluation of the broodmare and management of a mare having foaling problems. Evans indicated that "one of the highlights of the Symposium will be a live demonstratioof the use of ultrasound to examine the condition of the mare's reproductive tract. During the demonstration by Dr. Gary Webb, manager of the Texas A&M Department of Animal Science Horse Center, mares 247

with various reproductive problems will be examined and the images projected on a large screen for easy viewing by the participants." The problems encountered in transferring embryos from mares with uterine problems will be discussed by Dr. Mike Wilson. During the program devoted to the foal, orthopedic problems such as osteochondrosis, angular limb deformities and flexor problems will be emphasized. Dr. Jeff Watkins will start the session by defining the commonly misunderstood orthopedic problems of the foal. Dr. Jorge Auer who developed the technique of periosteal stripping to treat crooked legged foals will review various methods to treat the crooked legged foal. Dr. Nat Kieffer, geneticist and successful breeder of race horses, will discuss the hazards involved with selection for a single trait over several generations. Feeding programs to avoid developmental orthopedic diseases will be presented by Dr. Gary Potter. The facts (and fiction) concerning the copperzinc controversy will be addressed. Methods for successfully raising the orphan foal and early weaning to avoid transportation problems when broodmares are shipped to breeding farms will be discussed by Dr. Evans. More information concerning the symposium can be obtained from Dr. J. Warren Evans, Equine Sciences Program, Department of Animal Science, Texas A&M University, College Station, TX 77843 or calling 409-845-7731.

HORSE MARKETING: EXPANDING THE USER BASE Dr. A.N. Huff, Virginia Tech Marketing is one key to success in any business, including the horse industry. This takes many forms at the domestic and international levels. Horses are kept and sold for many uses and for a variation of prices (values) from a few hundred dollars to millionsof dollars accordingly. We need to promote and profit in all areas of opportunity. This article is not designed to downplay the importance of high value horses and the need to bring new dollars and larger investment into the industry. However, there may be one area being overlooked and this may be the ultimate or base lifeline of the horse industry. This area is the need simply to expand the user base, to get more people riding, using and enjoying horses. The market is people, millions of them and, thus, to a degree unlimited. Horses are kept for many reasons including business, sport and recreation. Around eighty percent of all horses are kept for recreation. Around forty percent of all horses are owned or ridden by youth. This should lead one to some obvious conclusions about marketing and the potential for ex-

248

panding the user base. Obviously, a new owner or even a new user attracted to and retained in the industry expands the market. This was essentially what brought about the boom in the light horse industry in the 1960's and 1970's. There are some indications and surveys that indicate that perhaps seventy percent or even more of current marketing is from one owner to another owner (a form of trading that did not really sell or expand the industry). Naturally, this is an important marketbut it should notdelude the industry to a degree so that a major effort is not renewed to really expand the owner, user and even the spectator base. The industry should organize and promote, advertise and develop the horse as a recreational, physical fitness, and mental improver program for humans. The industry, to a degree, has lost this cutting edge to golf, tennis, fitness training centers, etc. Some research has indicated that animals have a positive effect on our mental condition. The horse is a natural and it can be enjoyed by people of all ages and, yes, it could even be a glamour object with horse stars as "role models" such as our famous human athletes. The needs and opportunities and challenges are there. A few specific points may be offered as general recommendations in conclusion. Obviously, the list may be varied and reordered but the principles are there. • Organize, fund, advertise and promote the horse - in media that non-horse owners read, see and use. • Promote all breeds and uses of horses. • Develop andpromote morepublic riding - stables, rentals, etc. including basic instruction. •Develop more riding areas, trails, public horse use facilities and especially in the urban and suburban areas (where the people live). •Promote the horse as recreation, fun and sport and for physical and mental fitness for people of all ages. •Assist prospective new owners to receive instruction and help them locate sound, affordable, suitable and safe horses. We should stress the importance of pre-purchase examinations. •Promote all youth programs. Enroll more youth and volunteer leaders or instructors. •Promote and support all horse schools at all levels. •Place horse magazines in all school libraries and on as many public reading racks as possible. Each area or riding club or farm could do this on a local basis. •Develop programs that will permit average families to afford and use horses. -Produce sensible, safe, sound and useable horses for a novice public. •Promote and support all amateur programs.

•Produce horse events that will attract and retain public audiences (non-horse

owners). • Develop and promote more horse super stars (all breeds).

•Help to recycle useable horses from one owner to a new owner. •Promote the horse as an opportunity for challenge, accomplishment and enjoyment. This includes expanding the user base in more events and programs than in just the strictly competitive arena. •Educate the public to the fact that you do not have to be wealthy to use and enjoy horses. We need to develop simple and cost effective horse management programs for the average new owner. •Develop and implement urban horse keeping programs. •Finally, sell a horse to a new horse owner and to retain that owner as a satisfied horse person.

EQUINE LEUKOENCEPHALOMALACIA

IN MARYLAND HORSES Martin G. Robl, DVM, PhD According to veterinarians in the Maryland Animal Health Department, twenty horse deaths have been reported through February 15, 1987. These deaths have been associated with the disease called Equine Leuckencephalomalacia (ELEM). The deaths have occurred in 11 counties of central Maryland. This disease is attributed to feeding moldy corn to horses. The specific mold or mycotoxin has not been identified. However, a widespread soil mold called Fusarium moniliforme that affects kernels of corn grown during specific climatic conditions (drought) has been closely associated with ELEM in horses. The disease often occurs after corn is grown during dry or drought periods that are followed by a wet season that occurs after harvesL The initial symptoms of ELEM are drowsiness, loss of sight, muscular twitching, and staggering that is usually followed by paralysis and death. Some horses may die acutely with few if any symptoms observed. Even though Fusarium moniliforme and or a mycotoxin from this mold has been associated with ELEM, most attempts to reproduce the disease have been unsuccessful. Not enough information is known about how the toxin is produced and the biochemical nature of the toxin. Consequently,there is no test for the toxin and no antitoxin available for treatment. The diagnosis of ELEM in horses is associated with symptoms previously described and lesions present in the brain that consist of softening and liquifactionnecrosis of the white matter of the cerebrum. Some-

EQUINE VETERINARYSCIENCE

times typical lesions are not presenL In these cases, diagnosis is suspected if moldy corn has been fed and typical symptoms are observed.

LLAMAS BARRED FROM THE U.S. Sen. John Melcher (D-MT) loudly opposed USDA's announcement last January when Chile was declared free of foot-andmouth disease (FMD), thus clearing the way for importation of llamas from that country. Now he is thanking God (and a recent outbreak of EMD in Chile) for obviating the need for a congressional hearing on the issue. Sen. Melcher was quoted in the Washington Post as stating that "God, not having complete faith in our committee system, fortuitously intervened and revealed one of the infected critters." APHIS has since promulgated an interim rule to remove Chile from the list of countries considered free of rinderpest and foot-and-mouth disease. The action effectively prohibits the importation of cattle and other ruminants from Chile into the US as well as swine and the fresh, chilled or frozen meat of these animals. APHIS has also cancelled two other proposed regulations that would have allowed the importation of more llamas and alpacas into the United States. (From Veterinary Medical News)

NATIONAL HORSE YOUTH L E A D E R SYMPOSIUM Over four hundred horse owners, adult and youth, from eighteen states participated in the National Horse Youth Leader Symposium held at The Omni, Charlottesville, Virginia, on March 13-t5, 1987. The event was conducted by the American Youth Horse Council (AYHC) in concert with the Virginia Horse Council and ten additional institutions and organizations. Thirty-five speakers and twenty-five exhibits were featured. The theme focused on education and careers. AYHC is the youth educational arm of the American Horse Council and membership is open to all people interested in youth and horses. Details about AYHC may be obtained by contacting any of the following officers: President, Kay Davis Clements, American Morgan Horse Assoc., PO Box 1, Westmoreland, NY 13490: Vice President, Dr. A.N. Huff, Extension Horse Specialist, 380 Animal Sciences Bldg., Virginia Tech, Blacksburg, VA 24061; Secretary-Newsletter Editor, Sharon A. Davis, 6909 Brisbane St., Springfield, VA 22152; Ellen Melcher, Treasurer, American Saddlebred Horse Assoc., Kentucky Horse Park, 4093 Iron Works Pike, Lexington, KY 40511. The 1988 national symposium has been scheduled to be held in Denver, Colorado,

Volume 7, Number 3, 1987

January 22 and 23. This is an invitation for speakers, exhibitors, youth groups, colleges and schools and AYHC members to participate. These programs are also of value to high school and collegiate guidance counselors. For details: Dr. Ginger Rich, 1988 Symposium Chairman, Animal Science Dept., Colorado State University, Fort Collins, Colorado 80523 (303/491-6271). AYHC will also sanction regional symposiums with approval requests at least six months in advance in writing to any of the AYHC officers. The first regional event will be held on December 4-6, 1987, at Raleigh, North Carolina. For information: Dr. Bob Mowrey, Animal Science Department, North Carolina State University, Box 7621, Raleigh, NC 27695-7621.

OVERO CROSSES AND AGANGLIONOSIS By Keen Loeven Variation in overo spotting Abstract White foals born from overo parents die from colic during the first few days of life. The problem also is known as the White Foal Syndrome but should not be confused with the gene for dominant lethal white color. The overo condition involves abnormal development of the nervous system associated with the large and small intestines.

Introduction to Color Patterns Overo is a color pattern recognized by both the American Paint Horse Association and the Pinto Association of America, Inc. The other major pattern recognized by these organizations is the tobiano. The overo is a white spotting pattern where the white patches tend to be located on the horse's sides. The top of the animal's back is usually colored and the white patches do not usually cross over the back from one side to the other. The outlines of the spotting pattern are often jagged. The tobiano pattern, in contrast, tends to have white over the top of the back with patches spreading down the sides. This pattern usually has the dark color located on the horse's sides and there is less white on the face as a rule. The outlines of this spotting pattern tend to be smooth. The legs are generally white. The genetic mode of inheritance of these patterns has not been well established in the literature. However, we are reasonably sure that the tobiano pattern is a dominant trait. Reports have suggested that the overo pattern is basically a recessive trait but hard facts are lacking to support this idea. As you can see from the illuslration there is an almost infinite gradation of white and colored areas for both of these spotting patterns.

The White Foal Problem When breeders cross an overo mare with an overo stallion, completely white foals are sometimes born. Regardless of the sex of the foal, all die with signs of colic within 1 to 6 days. Most of these foals appear healthy at birth and stand and suckle the mare. They show signs of colic within the first 24 hours and usually are dead by 46 hours after birth. An overo pattern with considerable white should not be of concern in the newborn foal. True white foals have pink skin, pale blue eyes and may have only a hint of some pigment on the muzzle, hoof, stomach or some black tail hairs (less than 10% of the foals reported.) No reports exist of such a foal surviving and there is no surgical or medical treatment that can save the foal. A common misconception is that if the overo parents have a lot of white in their pattern that there will be a high incidence of these white foals. One recent survey disputes this notion by reporting white foals born to parents with less than 25% white, mere than 75% white and everything in between. In fact, white foals with this problemhave been born to non-overo mares that had ovem sires. For example, one of these foals was born to a buckskin mare and overo stallion where the buckskin mare had been sired by an overo.

Signs and Autopsy Findings The white foals are born normally and appear healthy. They develop a suck reflex from 1 to 20 minutes after birth. On average they stand within 1 hour and suckle the mare within 2 hours. However, they never pass meconium. Meconium is normally passed by the foal during the first 24 hours after birth and

249

appears as mucous covered, hard or pastelike pellets that are black or dark brown in color. The foals begin to show signs of colic within 5-24 hours (avg.=13 hours). These signs include straining to defecate, looking at their sides, unwillingness to get up, rolling, mild to violent thrashing, elevated respiration and heart rates and sweating or elevated body temperatures. On closer examination these foals have reduced but usually completely absent gut sounds and no feces in their rectums. These animals do not respond to enemas, which are often given to foals in order to help pass meconium. If there is time to do blood studies, the veterinarian finds normal values with the possible exception of some increase in white blood cells in response to stress. Since all of these foals die within the first week after birth, usually within 2 days, the rest of the picture is presented during the autopsy. The rectum and entire small colon are found to be pale, very small/narrow and tightly contracted. The small intestine is often distended and dilated with ingested milk while the cecum and large colon are distended with large amounts of impacted meconium. Other reports have indicated that varying portions of the large colon may appear constricted like the small colon and contain no meconium. The Cause - Aganglionosis Colic in the overo white foal syndrome is due to the impaction of meconium and ingested milk which leads to distention and severe pain. The meconium and milk are impacted because peristalsis fails to occur in the portions of the gut behind the impaction site. Peristalsis is the normal muscular activity in the wall of the gut that is responsible for moving food and feces backward. This muscular activity is much like a wave of contractions that passes along the length of the gut tube. Peristalsis is a highly coordinated event and is analogous to grasping a flexible piece of water-filled tubing with your fingers and stripping the water out as you hold one end and run your fingers down the length of the tube. Peristalsis, like any other muscular activity, requires nerves to trigger the contractions. However, the gut is unusual in that we can think of it as having its own, almost independentnervous system. In fact, the wall oftheguthas about the same numberof nerve cells as the entire spinal cord. Although there are "external" nerve fibers that connect with the gut and regulate its activity, most of the nerve cells are located inside the muscular wall of the gut tube in little groupings called myenteric and submucosal plexuses or ganglia. Aganglionosis literally means "without ganglia." When pathologists use the micro250

scope to examine the gut wall of these white foals, they fail to find these critical nerve ganglia in the small colon and they are also missing in all or parts of the large colon and even portions of the small intestine. Peristalsis that normally moves things through the GI tract cannot occur when there are no plexuses. In February of 1987 the New York State College of Veterinary Medicine's Pathology Department analyzed one of these white foals. Their report indicated an absence of myenteric and submucosal ganglia in the rectum, small colon, large colon and most of the small intestine. Another interesting finding in these cases is that the motor nerves going to, or the sensory nerves coming from these areas of the gut are intact and functional. An additional finding was a small, contracted small colon. One might very well ask why and how the small colon can get so tightly contracted when the nerve ganglia are absent. There is a difference between wellcoordinated peristaltic contraction and contraction of a segment of the bowel that is independent of neighboring contractions. The musclein the gut wall is smooth muscle and is not under conscious or voluntary control like the muscles of arms or legs. Smooth muscle is an "excitable" type of muscle which contracts on its own or if stimulated by irritation or stretching. One function of the myenteric ganglia is to control this tendency to contract (i.e., to inhibit contraction when appropriate). In the absence of this control, the smooth muscles contract and stay contracted. Early reports seemed to indicate that the colic was associated with a congenital stenosis of the colon or a condition called rectal atresia. Rectalatresiais a condition where the rectum fails to connect with the anus or open to the outside of the animal.These conditions generally do not appear in association with this syndrome but have been mistaken for what is actually a very tightly constricted small colon. The Developmental Problem Why does this condition occur? When during development does this happen? Why is there a relationship between the color of the foal and this problem? These are some of the many questions which have been and are currently researched. Initially it was thought that the problem involved a defect in the precursor cells which eventually become the nerve cells of the myenteric and submucosal plexuses. Very early in development a group of cells called the neural crest cells multiply and move to different areas of the embryo. These neural crest cells are critical in the development systems including the nerve cells of the gut ganglia.

The neural crest cells also develop into cells that eventually produce the pigments which are responsible for coat color. These cells are called melanocytes. Since the overo white foals do not have skin or hair color (remember that white is really the absence of coloration) and also lack myenteric and submucosal ganglia, many researchers felt that the problem originates with a malfunction of the neural crest cells. The hypothesis was that perhaps they fail to divide properly or fail to move to their proper location or fail to become the cells that they are supposed to become. Very recent studies indicate that this does not seem to be the case. Within the last three years we have learned that the problem stems from an inherent flaw in the gut wall itself rather than from a neural crest or nerve cell development defect. In carefully controlled studies researchers have shown that when the precursor cells of the myenteric/ submucosal nerve ganglia migrate to and reach the gut wall, something in the gut wall itself prevents them from entering the gut wall and assuming their proper positions for further development. It makes sense that the aganglionosis of overo white foals is not a defect of the neural crest cells since other parts of the nervous system of the foal (which also originate from this group of cells) seem to develop properly. Conclusion and Recommendations There is much which we still do not know concerning this syndrome. One of the largest gaps in our knowledge concerns the genetic basis and mode of inheritance of this condition. The syndrome of aganglionosis is not limited to the horse. Similar conditions have been found in conjunction with certain color patterns in mice. In humans aganglionosis comes in varying degrees of severity and is called Hirschsprung Disease. The most severe condition of this disease is called the Zuelzer-Wilson Syndrome which is very similar to the overo white foal syndrome and involves aganglionosis throughout the entire large intestine. In both mice and humans aganglionosis is inherited as a recessive trait. This mode of inheritance has not yet been established for the overo white foal syndrome. The research that is needed to determine the mode of inheritance will require careful analysis of breeding records and controlled test matings. Cooperation between the veterinary community, breeders and the two registries, the American Paint Horse Association and the Pinto Association of America, Inc. will be needed. Breeding recommendations then can be established which would help eradicate this deadly syndrome. (From Equine Rounds, a publicationof the Student Chapter AAEP at Cornell University, NYSCVM) EQUINE VETERINARY SCIENCE

WSU RESEARCH RECIPIENTS Research grants totaling $178,500 were awarded June 1, 1987 for investigations to be carried out through the Washington State University College of Veterinary Medicine's Equine Research Program. The projects are being funded through the WSU Equine Research Program's general state appropriations and other private funding sources of equine research support. The studies include: "The Interrelationship Between Locomotor Forces and the Physical Properties of Track Surfaces;" principal investigator, Dr. Marc Ratzlaff. In an effort to further understand the causes of track-related lamenesses, this initial study will focus on the relationship between the physical characteristics of the race track surface - - moisture content, harrowed vs. compact surfaces-- and the differences in forces exerted by horses galloping on these altered surfaces. "Further Investigatios Into the Causes of Fatigue in Skeletal Muscle of Exercising Horses;" principal investigators, Drs. Philip Gollnick, David Hodgson and Warwick Bayly. The goal of the research is to better understand the physiological factors involved in the onset of fatigue during exercise with special emphasis on the causes of exercise-induced disorders. "The Development and Evaluation of a Procedure for Prosthetic Replacement of the Equine Suspensory Apparatus;" principal investigator -Dr. Michael Major. The study will focus on the prosthetic replacement of the suspensory apparatus which would offer immediate joint stability and earlier painfree recovery to horses which suffer from traumatic disruption of the suspensory apparatus. "Effects of Pharyngitis and ExerciseInduced Pulmonary Hemorrhage on Airway Function and Athletic Performance in Horses"; principal investigator, Dr. W. Bayly. The study seeks to determine the exact cause of these two common respiratory problems. "Use of Somatosensory Evoked Potentials in Evaluation of Spinal Cord Disease in the Horse; principal investigator, Dr. Jennifer Allen. The aim of this study is to use SEP (somatosensory evoked potential) recordings, a non-invasive technique currently used in human medicine as a prognostic aid to evaluate neurological motor deficits in the horse. "An Investigation of Methods of Protective Immunization of the Equine Genital Tract;" principal investigator, Dr. P.R. Widders. Noting the association bacterial infection and infertility in the mare, the objective of the study is to investigate methods for stimulating a protective immune response in the genital tract of the mare.

Volume 7, Number 3, 1987

"Reversible Castration of Stallions: An Aid to Training;" principal investigator, Professor Jerry J. Reeves, Department of Animal Sciences}. The study will evaluate the effectiveness of LHRH (luteinizing hormone releasing hormone) decrease androgen production in stallions and thus reduce intractable behavior. The reversibility of the treatment on testicular function should occur in ninety days after cessation of treatment.

NEW AHC PROJECTS, PROGRAMS EMERGE FROM 1987 CONVENTION The American Horse Council's 1987 Convention, held June 7-10 in Washington, D.C., produced a number of new initiatives developed by the Council's advisory committees to be pursued during the upcoming year. Liability insurance problems continue to be a focus of attention for the horse industry, and at the request of the State Horse Council Advisory Committee (SHCAC), the AHC will be expanding its investigation of the problem and means to alleviate aspects of it. Under the direction of chair Carol Aim, the SHCAC itself will be increasing efforts to promote the development of new state councils, furthering what has become a promising national trend, and service the local groups with such items as guidelines for use by horse people in dealing with zoning issues. The American Youth Horse Council, AHC's youth activities arm, reaffirmed the general concern over insurance, noting in particular the negative impact the lack of insurance coverage can have on the entry of young people into horse sports. The AYHC also used its June 8 session, led by president Kay Clements, to review and extend its long standing commitment to improving educational programs and related information sources on careers and other avenues of participation for young people in the horse industry. The committee reviewed and urged expansion of AHC's involvement in video projects, brochures and other forms of industry marketing. Chairman Ed Roberts directedthe A H C Showing Committee through discussions of how to utilize the showing-related information provided by the recently-released AHC Economic Impact Study and AHC's future role in providing a forum for meetings of horse show managers and other showing groups.

AHC since has tentatively scheduled a show managers roundtable for November 13 in Denver, Colorado, to be followed by meetings of the State Horse Council and Show Committees on November 14 and 15. Further details are available from Mary Midkiff at the AHC office in Washington, D.C. The AHC Racing Advisory Committee, chaired by John A. Bell III, met June 8 and among its deliberations identified drug testing research as an ongoing major priority for the American racing industry. Forwarded to and subsequently endorsed by the AHC Executive Committee was a resolution that a subcommittee be appointed by the chairman to review the current status and future needs of drug testing research.

Research Leaders Meet Leaders in the equine research community, representing the U.S. Department of Agriculture, private research foundations, veterinary schools, researchers and veterinarians assembled on June 7 to discuss c o m m o n concerns. The discussions focused on problem

areas in the field and generated several ideas on how the research community might better carry out its vital role in improving horse health. Among the recommendations were communicating in a more systematic and effective way to the general public and "average" horse person the gains resulting from equine research; assisting the media in its coverage of these gains; developing structures and programs to encourage interested individuals to enter into and remain involved in the research field; and continuous reevaluation of research priorities. This was the second consecutive year that representatives of research groups met in conjunction with the annual meeting.

NEW APPOINTMENTS TO ADVISORY COMMITTEES American Horse Council president R. Richards Rolapp has announced a series of new appointments made by the AHC Board of Trustees to the Council's advisory committees. To the AHC Executive Committee, which oversees all Council activities: Billy Vessels, executive director, Florida Board of Business Regulation. To the AHC Health & Regulatory Committee: Dr. James Coffman, University of Kansas Veterinary School; Mike Nolan, executive director, American Association of Equine Practitioners: Dr. James Rooney, chairman, University of Kentucky Dept. of Veterinary Science; Dr. James Smith, Hagyard-Davidson-McGee Associates and the Kentucky Harness Commi.~sion.

251

To the Racing Committee: R. Anthony Chamblin, executive vice president, National Association of State Racing Commi.~sioners; John Giovanni, national managing director, Jockeys' Guild; Mike Steele, president, Horsemen's Benevolent and Protective Association. To the Showing Committee: Doe Etienne, Professional Rodeo Cowboys Association; Joy Meierhans, Horsemen's Council of Illinois; Robert Peebles, president, National Show Horse Registry; Fred Sarver, United Professional Horsemen's Association; Ron Thomas, executive director, The Celebration. The advisory committees monitor and coordinate AHC activities in their respective argas.

CUSTOMS USER FEE DISRUPTS U.S.-CANADA HORSE TRAFFIC The application by the U.S. Customs Service of a merchandise processing user fee has created problems in the movement of horses between the United States and Canada and has prompted the American Horse Council to write to the director of the Customs Service User Fee Task Force seeking clarification of the fee. The problems stem from legislation passed late in the 99th Congress which authorized the Customs Service to assess a fee on formal entries of imported merchandise. Regulations established the current rate at 0.22% of the value of the merchandise. The fee applies to all products entering the United States except certain goods specifically excluded. While foreign-bred horses imported for permanent entry into the U.S. are subject to the fee, horses imported for temporary purposes appear to be exempt. People who move horses between Canada and the U.S. have complained about problems related to the application of the fee on temporary entries and related Customs Service requirements. These problems fall into three general categories: that horse owners have been required to pay the fee when the entry of their horse(s) should be exempt based on the fact that the entry is temporary; that owners have been required to pay the fee numerous times for different border crossings involving the same horse(s); and that owners have been required to contract with a broker to facilitate temporary entry when, previously, they had been able to bring their horse(s) into and out of the country without a broker. In a July 2 letter to the director of the User Fee Task Force, AHC president Rich Rolapp said, "We hope that the Customs Service will recognize the unique situation created by the movement of horses between the U.S. and Canada and pursue some relief from the current, evidently troublesome,

252

regulations." Rolapp noted the special characteristics of imports of Canadian horses and the benefits generated through the participation of such horses in races, shows, rodeos, exhibitions and other events. He concluded that "aspects related to the application of the merchandise processing user fee threaten the economic gain that accrues to each nation through this interchange."

U.S. DEPARTMENT OF AGRICULTURE CONSIDERS CLOSING LOS ANGELES IMPORT STATION The U.S. Department of Agriculture (USDA) is considering closing its Los Angeles import inspection and quarantine facility which opened in 1984. With the publication of an advance notice of proposed rule-making in the Federal Register of July 8, 1987, the USDA is soliciting comments from the horse industry to assist it in making a decision about the future of the facility. Prior to 1984, a privately operated quarantine facility at Los Angeles International Airport was available for importing horses. The USDA opened its Los Angeles station before the 1984 Olympic Games to assure that sufficient quarantine space for all horses being imported for the Olympics would be available. Since that time, the USDA's facility has been underutilized, and revenues do not cover expenses. The private station has remained in operation and handles more than twice as many horses as the USDA facility. In addition, the costs associated with importing a horse through the private station are lower. If the USDA closed its Los Angeles facility, the overall costs of the Department's import operations might decline, thereby resulting in lower costs at other USDA stations. Written comments on the proposal should refer to Docket Number 87-085 and be submitted to Steven B. Farbman, assistant Director, Regulatory Coordination, APHIS, dSDA, Room 728, Federal Building, 6505 Belcrest Road, Hyattsville, MD 20782. For consideration, comments must be received at the USDA on or before September 8, 1987. More information about the issue and copies of the notice of proposed rule-making may be obtained from Wade Turner of the AHC staff.

SOUTH AFRICAN SANCTIONS AFFECT HORSE IMPORTS Horses are among the products affected by the Congressionally mandated sanctions imposed against South Africa to protest that Nation's policy of apartheid.

An amendment to the Anti-Apartheid Act passed by Congress last year prohibited the import to the United States of South African agricultural products or food. Subsequent regulations developed by the Treasury Department def'me agricultural products as all items classifiable in Schedule 1 of the Tariff Schedules of the United States (TSUS) except pets, stuffed or mounted animals, and skins of animals. Since horses are included in Schedule 1, imports of all South African horses, except those which might be defined as pets, are prohibited. It may be possible for a horse to be classified as a pet for purposes of entry, provided the horse meets certain conditions. A horse could be considered a pet provided it is imported for personal purposes and the owner will not receive any commercial value from the horse. Horse owners who pursue imports of horses as pets are cautioned that each entry is examined by the Customs Service on a caseby-case basis, and it is wise to seek clarification regarding the entry through Treasure prior to import.

NATIONAL TRAILS IMPROVEMENTS ACT CALLS FOR CONVERSIONS AND ACQUISITIONS On June 10 Rep. Beverly Byron (RME)) introduced in the House of Representafives H.R. 2641, the National Trails System Improvements Act of 1987. The bill currently has 16 co-sponsors. H.R. 2541 calls for two new programs that would directly benefit trail users. One component of the legislation encourages the conversion to recreational trails of abandoned railroad right-ofway on federal land by keeping such rightsof-way in the public domain. The other feature is the establishment of a Trails Development Revolving Fund to provide state and local agencies and private organizations with resources to acquire and develop trails. This program would be financed through sales of rights-of-way unsuitable for trails use. The National Trails System Act of 1987 addressed in a positive, inexpensive manner some major concerns of trail user groups. The legislation is also entirely consistent with the goals stated in the report of the President's Commission on Americans Outdoors which recognizes the need to encourage development of trails from abandoned railroad rights-of-way as a part of the Greenways for America recommendation. Interior and Insular Affairs Committee, a companion bill, is expected to be introduced in the Senate by Howard Metzenbaum (D-OH).

EQUINE VETERINARYSCIENCE

HOUSE APPROVES FUNDING FOR TRAILS ASSISTANCE The House Appropriations Committee approved increases in the National Park Service (NPS) budget for fiscal year 1988 for rivers and U'alls technical assistance programs. Trails groups are seeking more funds to enable the NPS to carry out programs designed to assist state and local agencies with inventories, planning and management of trails. The House Committee approved an increase of approximately $900,000 over current funding for joint rivers and trails assistance programs, with nearly $400,000 earmarked specifically for trails. While these gains are encouraging, the Senate has yet to take action on these items. Trail users are encouraged to urge their Senators to support funding for NPS trails technical assistance programs.

POST-BREEDING MARE CARE Frederick Harper, PhD University of Tennessee Every broodmare manager wants a normal, healthy foal from each broodmare yearly. As soon as the pregnant broodmare arrives home from the breeding farm, this objective becomes the sole responsibility of the mare owner. Obtaining this goal depends greatly upon proper management.

Nutrition The nutritional need of the non-lactating broodmare during early pregnancy are those of maintenance (Table I). Early pregnancy covers the f'wst eight months of pregnancy. All horses have a maintenance requirement for all essential body functions. A maintenance level of nutrition is required during the first eight months of pregnancy because only 40 percent of the fetus, placental membranes and fluids (fetalplacental unit) development occurs during this time. The fetal-placental unit will weigh about 130 pounds in a 1,100-pound mare. This represents only about 0.2 pound of increase per day during early pregnancy. A maintenance diet will support this rate of gain. Lack ofpropernutrition may play arole in early embryonic death. Approximately 0.8 pound of total digestible nutrients (TDN, an energy equivalent) is required per I00 pounds of body weight for maintenance Gable I). Therefore, Volume 7, Number 3, 1987

a 1,100-pound broodmare needs 8.8 pounds of TDN daily for maintenance, whereas a ! ~200-pound broodmare requires 9.6 pounds. The National Research Council (NRC) recommends about 7.7 percent crude protein for mature maintenance horses. Other data indicate the level of protein should be approximately 6 perconL Since protein is usually the most expensive feed ingredient, overfeeding protein is not only unnecessary but highly expensive. The maintenance requirements of calcium and phosphorus are 0.27 percent and 0.18 percent, respectively. For a 1,100pound broodmare, this is 23 grams of calcium and 14 grams of phosphorus daily. Early pregnancy normally occurs during the spring or summer. Energy, protein, vitamin and most mineral requirements are met by pasture forages. Good quality pasture, the basis of all horse feeding programs, will meet the nutritional needs of these mares. Proper liming, fertilization and management of horse pastures are essential. Feeding of grain is not necessary on good pasture. A major concern during early pregnancy is getting non-lactating mares too fat. Obese broodmares are undesirable. They have trouble foaling due to a lack of muscle tone and because of fat deposits encroaching on the birth canal. They are also difficult to rebreed. If grass pasture constitutes the summer grazing, a2:l ratio of calcium to phosphorus mineral supplement is recommended. A 50/ 50 mixture of trace mineralized salt and dicalcium phosphate or steam bone meal is adequate. A low calcium, high phosphorus mineral should be used when clovers constitute a high percentage of summer pastures, since legumes are high in calcium content. Mix equal parts of trace mineralized salt and monosodium phosphate, or equal parts of U'ace mineralized salt, monosodium phosphate and dicalcium phosphate. The result is about 8 percent calcium and 16 percent phosphorus mineral mixture. Trace mineralized salt should always be available in addition to the mineral mix.

Lactating broodmares have a greater nutritional need than pregnant broodmares (Table I.) Milk production increases until the second or third month of lactation, then dec r e a s e s until the foal is weaned. A broodmare will produce 2 to 3 perc~mt of her body weight as milk. To produce this quantity of milk and to sustaina high level of production during the first two to three months requires a considerable increase in all nutrients. Based on recent data, the daily energy requirements of lactation during the first three months is from 1.25 to 1.40 pounds of TDN per 100 pounds of body weight. The crude protein needs are 12.5 percent of the dally ration. Many breeders feed more protein than the amount recommended by NRC. The requirement for calcium is 0.45 percent and 0.30 percent for phosphorus or 50 and 34 grams per day, respectively, for a 1,100pound broodmare. Mares in the first90 days of lactation will need a grain supplement in addition to good pasture. About 0.25 to 0.75 pound of grain per I00 pounds of body weight daily may be necessary. If no pasture (dry lot)or poor quality pasture is available, I to 1.5 pounds of good quality hay per I00 pounds of body weight should be fed with an equal amount of grain. Legume hays are preferred at this time. After eight to 12 weeks of lactation, it is more efficient to feed grain directly to the foal. The energy and protein needs decrease as milk production goes down. Decreasing grain intake to broodmares which are on good quality pasture will not be detrimental. Slight weight loss occurring in broodmares during the last 90 days of lactation is not harmful. There is a five month time period to recondition the mare before her next foal. If pastures are dry and are of poor quality,andl or foalsare not creep fed, feeding grain to the mare throughout lactationmay be necessary. Mineral mixes noted above should be provided.

Virus Abortion Abortion in horses is expensive and

TABLE 1. Nutrient Requirements of Early Pregnancy and Lactation

Energy (Ibs TDN per 100 Ibs. body weight) Protein (% CP)'

Eady pregnancy 0.8 7.7

Early lactation 1.25-1.40 12.5 (13-14) ~

Late lactation 1.10 11.00 (12-13)s

Calcium (%)

.27

.45

.40

Phosphorus (%)

.18

.30

.25

11.00

25.00

20.00

Vitamin A IU/Ib. b.w.'

'Percent crude protein qntemalJonalUniVpoundof bodyweight ~(Levelfed by many horse owners) 253

often an unnecessary loss. Many abortions are due to equine rhinopneumonitis, commonly called virus abortion. Pregnant mares can be vaccinated against the abortion phase of the disease by the use of a killed vaccine in the fifth, seventh and ninth months of pregnancy (Pneumabort K, Ft. Dodge). Mares mustbe immunized each year. This disease is first observed in the late fall or early winter as a respiratory disease in young horses. The larger the horse population and the more traffic of horses into and out of a farm, the more severe the problem. Pregnant mares exposed to the virus may abort several weeks to several months after the virus has spread through the young horses. Most abortions (86 percent) occur in the last three months of pregnancy, usually without warning or stress on the mare. Foal death occurs during the first day or so of life. The mare's reproductive ability is not impaired. Most mares which abort can be rebred in the second estrus. A high percentage of mares on a farm is usually affected. Abortion storms may result in 60 percent loss of the foal crop.

Parasite Control The broodmare should be on a scheduled year-round parasite treatment program being treated every 60 to 90 days. It is possible that the broodmare was not dewormed while at the breeding farm. If this was the case, start her on a routine program about two weeks after she returns home. There are some restrictions of dewormer products for use in pregnant mares. Most veterinarians do not recommend the use of organophosphate products during the first and last third of pregnancy. The product Camvet (a benzimidazale) is not recommended during the first third of pregnancy. It is advisable that every horse breederdevelop a complete deworming program with a veterinarian for all horses on the farm.

Hoof/Tooth The broodmare's feet should be inspected as soon as she returns from the breeding farm. Her feet may require immediate attention if they were not trimmed at the breeding farm. Since most broodmares are on pasture, hoof growth may equal its wear. There are situations when the feet require trimming of excess hoof growth. The feet should also be trimmed periodically to maintain proper shape and angle. If allowed to grow too long, the hoof wall often breaks off into sensitive areas resulting in lameness. On extremely rocky or hard ground, the hoof wall may wear down too much. In such situations, broodmares may have to be shod in front. If possible, mares should not be shod since there is always the possibility of them pawing and getting a foot caught in wire fences.

254

Regular inspection and trimming when necessary will resolve the majority of foot problems in broodmares. There are certain conditions, such as founder, which require broodmares to be shod with pads to provide them comfort, as well as protect the hoof. Chronic pain which can be caused by lameness may result in mares not cycling normally, and has been incriminated in abortions. Teeth problems should be suspected when considerable whole grains appear in the manure, when they eat slowly, hold head to one side when chewing or chew in an openmouth fashion with grain falling to the ground. Thin mares and older mares are also likely to have teeth problems. Broodmares with any of these symptoms should have their teeth checked.

Pregnancy Test Mares are usually diagnosed pregnant by a rectal examination by a veterinarian at about 35 to 42 days. It is good insurance to reexamine mares at 100 days post-breeding and again in the fall, usually about early October. It is essential to discover those mares which were bred but are not currently pregnant. The breeder and veterinarian have several months before the next breeding season to determine why the mare is open, treat her and make management decisions about getting her pregnant next year. Waiting until next spring to find out that a mare is open does not allow adequate time to correct a problem, such as an infection, and get the mare pregnant within the regular breeding season (spring and early summer). Pregnancy testing at 100 days is especially helpful in this respect. It is advantageous to culture and treat mares during a heat period. There are enough warm days for the open mares to cycle and provide an opportunity for culture and treatment in the summer and fall. A major management decision for the breeder is whether to keep or to cull open mares. Older mares which did not produce a current-year live foal and are open are likely candidates for culling. These mares may not have a high market value, but the breeder must consider the cost of keeping them for another 24 months versus the potential economic return two years away. Added to this cost is the probability that the mare will not become pregnant next spring. Once older mares (past 17 years of age) skip having a foal for a year, they are more difficult to get in-foal. Once a broodmare is pregnant, one problem is solved. Careful management of the pregnant mare is essential to protect one's financial and genetic investment.

Pasture for Broodmares

pasture for broodmaresT' August and September is the time to plant cool-season pasture forages. The following are considerations for broodmares:

Planting a new pasture 1. First consider a non-fescue forage such as Orchardgrass, Kentucky Bluegrass, Bermudagrass, etc, Soil type and management factors will aid you in deciding on the pasture forage. Consult with your county Extension agent for soil test, best variety for you soil type, specific pasture management recommendations, etc. If fescue is the forage grass of choice, you should plant one of the new low-endophyte varieties. These varieties are: Johnstone, Kenhy, Forager, Alta, Missouri 96 and AU Triumph. Seeds from these varieties may not be readily available. Management of these varieties may be more critical than with Kentucky 31. These varieties may not stand heavy grazing pressure. The addition of clover, up to 40 percent is recommended.

Renovation of existing fescue I. Test the fescue for level ofendophyte infestation. Broodmares may be all right on an extremely low level of endophyte infestation. There were no problems noted in a Kentucky study with broodmares on a 7 percent endophyte fescue pasture. 2. Consult with your county Extension agent on how to kill existing fescue pasture chemical spray or mechanical (plowing or disking) 3. Reseed pasture as noted above.

NO Sorghum-Sudangrass A dry spring can result in pasture shortage in some areas. Summer annuals are used as supplemental or replacement pastures. Sorghum-sudangrass hybrids, sudangrass or sorghums should not be grazed by horses. Pregnant mares may abort or give birth to deformed foals if grazed on sorghum-sudangrass hybrids or sudangrass. Horses grazed on sorghum-sudangrass hybrids or sudangrass may become toxic, with death occurring in some instances. Incoordination in the rear quarter may appear when the horse is stopped, turned or backed. A cystitis occurs because of a malfunctioning bladder resulting in urine dribbling which causes urine scald. The urine is very thick and a dark yellow to brown color. Death results from kidney failure. Hay from the sorghum-sudan hybrids or sudangrass can be fed to horses if properly cured and stored. These are generally a poor quality hay. There is no effective treatment for the poisoning causing ataxia or cystitis. Do not graze horses on sorghum-sudangrass pastures. (From University of Tennessee

Horse Express)

A common question is, "What is a good

EQUINE VETERINARYSCIENCE