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• Hypothyroidism in foalsd
• Pleasure horses have ulcers, too
  • Description of each case
• Degenerative ligament disease reaches beyond the limbs
• University of Maryland to host 2007 Equine Science Society Symposium
• 2006 Hambletonian festival of racing includes cutting-edge veterinary education, sponsored by Pfizer Animal Health
• EVA outbreak and vaccine shortage affecting Western United States

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Hypothyroidism in foalsd 

If a foal is born late, but is immature in other ways, hypothyroidism may be the cause. Hypothyroidism is a condition in which there is an unusually low level of certain thyroid hormones in the blood.

Signs most often associated with this problem in foals include prolonged gestation, an underbite (“monkey mouth” or prognathism), contracted tendons, and, in some cases, rupture of the extensor tendons. In severe cases, the foal may be unable to stand and suckle on its own.

Affected foals are usually normal sized or large, but they may have immature physical characteristics, such as soft, pliant ears and a silky hair coat. Importantly, some bones, especially in the hock and carpal joints, may be incompletely formed, which is known as hypo-ossification.

Although hypothyroidism can be difficult to accurately diagnose in adult horses, the signs can be quite clear in newborn foals. “Its official name is Congenital Hypothyroidism and Dysmaturity Syndrome (CHD), and it is one of the few documented syndromes of hypothyroidism in horses,” said Dr. Melissa Hines, an associate professor in equine medicine at WSU, who has diagnosed and treated many cases.

“We don't really know what causes CHD, but it does not appear to be related to genetic predisposition,” she said. “It is theorized that the syndrome may be related to mustard weed consumption by pregnant mares based on epidemiological studies, as well as a lack of mineral supplementation—selenium in particular. Some also suspect nitrates in forage may be a culprit, too.”

Cases of the syndrome can be found throughout the United States and parts of Canada. It is most frequently seen in the Pacific Northwest and western Canada. Interestingly, not all foals in the same herd or location will be born with the syndrome.

“Even in the same location, weather conditions and the amounts of plants growing when mares have access to pasture may be different from year to year,” Dr. Hines said. “In addition, individual mares may have different grazing habits. We see cases of CHD in which eight to ten foals may be affected in one area in one year, but later on, there won't be any cases.”

In addition, mares that have foals with hypothyroidism are themselves unaffected. They may also give birth to normal foals in the future. One exception may be mares that seek mustard plants out as forage.

The mustard plants of concern are of the Brassica species, including shepherd's purse (Capsella bursa-pastoris), blue mustard (Chorispora tenella), flixweed (Descurainia sophia), clasping pepperweed (Lepidium perfoliatum), field pennycress (Thlaspi arvense), and tumble mustard, also known as Jim Hill mustard (Sisymbrium altissimum). These plants may contain a chemical toxic to horses called glucosinate, which is carried in the seeds and vegetative parts of developed plants, whether the plant is fresh or dry.

“We don't know at what point in the pregnancy foals are affected,” Dr. Hines said. “It may be that some foals are affected early on and are aborted. It is thought that most foals born with the syndrome are affected in the latter part of gestation.”

“We recommend keeping foaling mares away from mustard weed stands during pregnancy, and avoid feeding hay that is heavily contaminated with mustard weeds,” she said. “Owners can also supplement their mares with trace minerals, especially selenium.”

CHD is confirmed through thyroid testing and biopsy of the thyroid gland. Because CHD signs in affected foals are so unique, many veterinarians will make a presumptive diagnosis based on observations rather than laboratory testing.

In most cases, the thyroid gland is not noticeably enlarged, but when microscopically examined, it is very hyperplastic or abnormally enlarged. Hyperplasia causes the cells to be crowded and have decreased levels of colloid, a substance that helps cells produce thyroid hormones.

The thyroid gland produces hormones that are important for the proper growth and development of all animals. The lack of thyroid hormones seen in CHD cases causes foals to be underdeveloped and have a number of musculoskeletal deformities. The severity of the syndrome varies from foal to foal, ranging from mild to severe.

“There is no specific treatment for CHD, and the affected foal's thyroid will actually become normal over time, usually within a few months,” Dr. Hines said. “The long lower jaw will also correct over time, but the lack of bone in the legs may cause deformities in the foal before the bone can form normally.”

Because of these problems, even in mild cases, foals will need supportive care, and their musculoskeletal problems will need to be managed. Whether thyroid hormone supplementation benefits foals is unknown.

Foals with contracted tendons may not be able to stand to nurse and will need help from their owners. This is very important because many complications can result if the foal does not get enough colostrum from its mother. Colostrum, or the mare's first milk, contains protective antibodies that foals need to fight infections. Without it, a foal may develop a fever, decreased appetite, diarrhea, pneumonia, and other complications that can be deadly.

For bone deformities, radiographs can be taken of a foal's knees and hocks to determine how underdeveloped the bones are. Splints and restrictive exercise can be used to help foals with very weak bones. As they grow, their bones will eventually become stronger and the splints will help their bones form correctly. Later in life, foals that have been significantly affected may have problems with arthritis and joint disease.

For more information about CHD, contact the WSU Veterinary Teaching Hospital at 509-335-0711 or Dr. Melissa Hines at 509-335-0765 or mth@vetmed.wsu.edu.

Reprinted from: Washington State University Veterinary Teaching Hospital Equine News website: http://www.vetmed.wsu.edu/depts-vth/EquineNews/

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Pleasure horses have ulcers, too 

Research has shown that 90% or more of high-level performance horses have gastric ulcers, and that lower-level show horses also can get ulcers, but at a lower rate. The Horse and Merial (manufacturers of GastroGard and UlcerGard, ulcer treatment and preventive) joined forces with Rood and Riddle Equine Hospital in Lexington, Kentucky, to have some pleasure and low-level show horses examined for ulcers to see whether the average horse suffers from stomach ulcers.

Fifteen low-level show horses (shown a few times a year) that “weren't doing quite right” in central Kentucky were recommended by their veterinarians to take part in an endoscopic survey on April 16. Some horses were recommended because they ate a lot of feed and never gained weight, whereas others displayed nervousness, teeth grinding, and a poor hair coat. These 15 horses were turned out every day, with fairly stress-free lives.

Each horse was trailered to Rood and Riddle Equine Hospital and examined with an endoscope by internal medicine specialist Bill Bernard, DVM, Dipl. ACVIM. Also on hand was Stephanie Thompson, DVM, manager of veterinary technical services at Merial.

The actual scoping procedure for each horse lasted less than 10 minutes and was done under sedation using Boehringer-Ingelheim's new tranquilizer Sedi-Vet. The sedative causes less ataxia (incoordination) than other sedatives currently available and helps the horse wake up faster; the horses stand quietly, but can walk away after the procedure without stumbling.

Eight horses were diagnosed with ulcers (53.3%). These ranged in severity from “healing ulcer ridge that looks like a volcano” to a “slight reddening in one portion of the stomach,” according to Bernard.

Thompson discussed with each of the horse owners the best use of UlcerGard for their particular situations.

For horses that do not travel to shows on a regular basis, she recommended that owners use UlcerGard during times of stress, such as with varied feeding practices, changes in routine, and before any traveling.

Description of each case 

For each horse that was diagnosed with an ulcer, the owner was given instructions to begin a preventive program with their veterinarian. Those horses that did not have ulcers, but had underlying causes of poor health, were told to have further testing performed by the veterinarian to find the cause. Thompson recommended that each horse, regardless of the outcome of the endoscope procedure, use UlcerGard during times of stress to prevent ulcer formation.

The first horse examined was Panache, a 7-year-old sport horse who has been worked under saddle for 2 years and was already schooling 4th level dressage and showing in 3′9″ jumper classes. She had been showing in Florida during the winter, but had been at home for the past 3 weeks. Her owner said she was kept on a regimen of UlcerGard while he was traveling because she did not eat well. Panache's stomach was normal and ulcer-free.

Crafty is a 12-year-old English Thoroughbred who competes at the preliminary level in events. He has had the past year off, and he was acquired 3 weeks ago by his owner. Crafty eats beet pulp and 6 pounds of sweet feed each day, along with hay and grass during turnout. Although he was not displaying any overt clinical signs of having an ulcer, his owner wanted to see whether he was healthy because she just purchased him and didn't know his history. Crafty's stomach appeared normal.

Reality H, a 10-year-old Oldenburg stallion, competes in eventing, dressage, and jumper classes. He has the same feed schedule as Crafty because they live on the same farm. Reality was on GastroGard a few months ago because he went off his feed, but his owner did not know whether he had an ulcer at that time because he was not scoped. “He improved with the medication,” his owner said. Bernard found no abnormalities in his stomach.

Nipos, a 10-year-old Dutch Warmblood, competes in training and 4^th-level dressage. He eats sweet feed with corn oil, alfalfa, grass hay, and gets 8 hours of turnout per day. His owner did not seem to think he had an ulcer, but said he appeared thinner than he should be. Bernard said, “He has a healing ulcer ridge that looks like a volcano.” Thompson recommended that Nipos be treated with GastroGard, then placed on a program with UlcerGard because something in Nipos' environment is causing him to be susceptible to ulcers.

Cajun is a 7-year-old Thoroughbred who competes in the local jumper ranks. He is said to eat a huge amount of feed, but you could count the ribs on his body. Bernard found a slight irritation in Cajun's stomach lining, but he did not have an actual ulcer present. Cajun's owner was sent home with instructions to use UlcerGard because he appears susceptible to getting an ulcer.

Little John is a 12-year-old New Zealand Thoroughbred that just underwent a series of joint surgeries. “We wanted to make sure he wasn't sick from the stress of the surgeries before we started competing,” said his owner. Little John is also prone to quickly dropping weight even though he eats more feed than any other horse in the barn. Bernard found a grade 1 ulcer.

Rocky, an 8-year-old Thoroughbred hunter, is described as “kind of a fretful horse that worries a lot. He's nervous at shows, but manages to keep weight on,” said his caretaker. Rocky has the same meal plan as Cajun. Bernard said his stomach was normal.

Buzz, a 5-year-old Thoroughbred that is unsound except for walking, is very thin and in overall poor condition despite his voracious appetite, ample turnout, and good attitude. Bernard found Buzz's stomach to be normal, and said Buzz would need a full veterinary examination to find the underlying cause for his weight loss.

Majestic, an 8-year-old event mare, lives outside and showed just a few weeks ago. She eats quality feed pellets and corn oil, but is still thin. Shows do not create any behavioral changes in Majestic, says her owner. Bernard found her to have “good constitution of her stomach”; no ulcers were present.

Coffee, a 17-year-old appendix Quarter Horse, shows twice a year in local hunter and jumper classes. He eats a cup of sweet feed twice a day, and he spends half of his time outside. He receives a lot of medication for his low ringbone and arthritis, but he was found to have a normal stomach.

Chess, an 8-year-old Thoroughbred, events at the novice level. He eats pellets, corn oil, and hay, and he is outside at night. Chess just returned from a horse show in Florida. His owner was concerned he might have an ulcer because Chess grinds his teeth when ridden. Bernard found “a slight reddening in one portion of the stomach,” which signals a potential site for an ulcer to form. Bernard called Chess' ulcer a grade 1, and Thompson recommended treatment with GastroGard followed by UlcerGard to prevent another ulcer in the future.

Keswick is a 14-year-old preliminary event horse competing at summer shows. She lives on the same farm as Chess. “She doesn't carry weight very well, has a dingy coat, and doesn't eat in the barn very well,” said Keswick's caretaker. “She also choked twice this past month, so now her feed is soaked.” Bernard found a grade 1 ulcer in Keswick's stomach.

Scotty is a 12-year-old event horse who is starting training level. He shows throughout the year, and his owner recently noticed he dropped a lot of weight last month. “He hasn't picked up any weight since,” she said, despite his diet of pasture, soybean meal, and grain. Scotty also cribs. Bernard found a grade 1 glandular ulcer. “Horses that have ulcers in the glandular portion (fundic, or bottom section) of their stomach are susceptible to ulcers in the duodenum as well, but it is hard to see down there (during a scoping procedure) because of the fluid that is still present in the horse's stomach,” commented Thompson. Glandular ulcers are less common—approximately 15% to 20% of all ulcers—but she said, “Every horse is an individual.”

Bonus is a 9-year-old Thoroughbred who foxhunts two times a week during the hunt season. He eats hay, grain, and pasture. His owner said, “He'll go through bouts where he won't eat grain, but tears into his hay and eats it up quickly.” She mentioned that Bonus has had several bouts of colic recently, and Bernard discovered a grade 1 ulcer.

Farmer is a 10-year-old Throughbred who also foxhunts. He lives on the same farm as Bonus and has the same feed schedule. Farmer's owner commented on the roughness of his coat and likened it to sunburned hair. “He's dropped a lot of weight lately, even though he's as fit as he's ever been,” she said. Bernard also found a grade 1 ulcer in Farmer's stomach.

Reprinted with permission of The Horse; visit www.TheHorse.com for more horse health news.

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Degenerative ligament disease reaches beyond the limbs 

Researchers at the University of Georgia (UGA) College of Veterinary Medicine have discovered that degenerative suspensory ligament desmitis (DSLD), a common disorder in horses once thought to involve only ligaments in the legs, actually affects connective tissue throughout the body.

As a result of the finding, lead author Jaroslava Halper, MD, PhD, and her colleagues recommend that DSLD be renamed to reflect more accurately the disorder's true nature.

“It's a systemic disorder involving accumulation of proteoglycans (a class of molecules that help organize connective tissue so that it is elastic yet strong),” said Halper, an associate professor of pathology. “So we propose equine systemic proteoglycan accumulation, or ESPA, as a more appropriate name for the condition.”

The disorder affects an estimated 1% to 7% of horses, and it is most commonly detected in Peruvian Pasos. It also affects Arabians, American Saddlebreds, American Quarter Horses, Thoroughbreds, and some European breeds. Affected horses become lame as the lower portion of the leg swells. There is no cure, so horses with advanced cases of the disorder are often euthanized.

“The impact of this disease is huge,” said coauthor P.O. Eric Mueller, DVM, PhD, Dipl. ACVS, professor of surgery and chief of staff at the UGA Large Animal Veterinary Teaching Hospital. “These are young horses that should be at the pinnacle of their performance that start to drop at the fetlock and show lameness.”

Halper said the first clue that DSLD/ESPA was a systemic disorder was the anecdotal evidence that horses with the disorder—which tends to run in families—are known to suddenly develop fatal aortic ruptures. Similarly, people with Marfan syndrome, an inherited disorder of the connective tissue, are prone to sudden death of aortic ruptures.

She also had trouble believing that only the suspensory ligament of the lower leg would be affected by the disorder. She reasoned that a horse is likely to have trouble walking if its weight-bearing suspensory ligament is damaged, but connective tissue elsewhere in the body could also be diseased without a horse altering its behavior.

“It just didn't make any sense to me that the disorder would be localized to the suspensory ligament,” Halper said. “So I started to look at other tendons and ligaments.”

Halper and her colleagues examined tissues and organs from 28 horses with the disorder and from a control group of eight horses that did not have the disorder. When viewed under a microscope, tissues from other ligaments in the body as well as vessels and organs with significant amounts of connective tissue, such as the aorta, appeared diseased. Specifically, the tissue had an accumulation of proteoglycans.

The finding has made the researchers' results, published in the journal BMC Veterinary Research, the third most widely read article in the journal's 2-year history. The article was published in April and was the most frequently read article for 3 months.

The finding has also led the researchers to study a new diagnostic test for the disorder. By examining a thin sliver of tissue—approximately the size of a human fingernail—from the large ligament on the back of a horse's neck under a microscope, veterinarians can detect the excess proteoglycan accumulation before a horse starts displaying clinical signs.

Because the disorder tends to run in families, horse owners can choose not to breed predisposed horses. Owners can also manage predisposed horses so that they place less stress on the weight-bearing ligaments of the legs to potentially reduce the likelihood of lameness.

“Now we have a relatively simple, safe technique that can identify predisposed horses,” Mueller said. “As we do this work and link it to genetic studies, we can ultimately minimize the incidence of the disease through selective breeding.”

Reprinted with permission of The Horse; visit www.TheHorse.com for more horse health news.

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University of Maryland to host 2007 Equine Science Society Symposium 

The University of Maryland will serve as the proud host of the Equine Science Society Symposium to be held June 5 through 9, 2007 in Hunt Valley, MD. The Equine Science Society (formerly Equine Nutrition and Physiology Society) promotes quality research on equine nutrition and physiology and strives to establish effective communication among researchers, teachers, extension, and production personnel. The symposium will feature scientific presentations of original research, guest lectures from horse industry experts, and social activities including a tour of a selected number of farms from Maryland's rich horse industry. The event will be held at the Baltimore Marriott Hunt Valley Inn (410-785-7000), which is conveniently located 20 minutes from Baltimore's Inner Harbor and 35 minutes from the Baltimore Washington International Airport.

For more information on the 2007 ESS Symposium, contact Kristen Wilson at 301-405-1392 or kswilson@umd.edu. Additional details can be found on the ESS website at http://www.equinescience.org/.

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2006 Hambletonian festival of racing includes cutting-edge veterinary education, sponsored by Pfizer Animal Health 

Equine veterinarians from around the country gathered during this first week of August at the Meadowlands Racetrack to participate in a wide range of educational seminars during the 2006 Hambletonian Festival of Racing, sponsored, in part, by Pfizer Animal Health. This was the Seventh Annual Continuing Education Seminar for Equine Veterinarians, and it was also the first time the Meadowlands Racetrack had offered veterinarians an opportunity for hands-on learning through a special “wet lab” program, held August 3.

Wet labs allow veterinarians to do more than just hear about the latest advances in veterinary medicine; they offer the chance to practice these techniques with other professionals in a collaborative environment. One of the featured laboratories in this year's program was designed to help equine veterinarians more effectively administer intra-articular injections to horses—an important pain management and joint-healing tool for the performance horse.

This wet lab was conducted by G. Kent Carter, DVM, MS, DACVIM, Professor of Large Animal Internal Medicine at the College of Veterinary Medicine at Texas A&M University in College Station, TX. Dr. Carter also serves as Large Animal Medicine Department Chief and has published and lectured both in the United States and abroad.

“As long-time sponsors of the Hambletonian Festival of Racing and the Continuing Education Seminar, we are extremely proud to have been part of the inaugural year of the Veterinary Wet Labs program,” said Kathy Miranowic, Equine Product Manager at Pfizer Animal Health. “Joint injections are an important therapeutic tool for veterinarians who work with high performance horses in a variety of sports. Dr. Carter's wet lab on the subject—as well as the four other wet labs taking place during the day—will help further veterinary education on this key topic.”

When it comes to joint injections, Pfizer Animal Health offers a leading product to help heal horses' joints. Hylartin(R) V (sodium hyaluronate) injection lubricates joint tissues, reduces friction, and improves joint action. The product goes straight to the problem area and replenishes natural hyaluronate for long-term recovery. As with all intra-articular injections, occasional mild side effects may include heat, transient edema, and pain around the injection site. For more safety information, please go to www.equineresources.com/pdf/HylartinVinformation.pdf for full prescribing information.

For more information on Pfizer Animal Health's complete line of equine health care products, visit www.pfizer.com/equine. Pfizer Inc discovers, develops, manufactures, and markets leading prescription medicines, for humans and animals, and many of the world's best known consumer products.

Media Contact:Equine Resources International, LLC610-444-7554

teresa@equineresources.com

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EVA outbreak and vaccine shortage affecting Western United States 

An outbreak of equine viral arteritis (EVA) has resulted in quarantine restrictions in 18 states, with nine states reporting positive cases. A vaccine shortage is hampering efforts to control the outbreak.

Although the virus has thus far been limited to Quarter Horse breeding farms, Peter Timoney, FRCVS, PhD, of the University of Kentucky's Maxwell H. Gluck Equine Research Center, sees an opportunity for transmission into the Thoroughbred industry because the breeds often share the same areas at tracks and are often crossbred.

Strains of the virus active at this time are clearly abortigenic,” said Timoney. “People need to be very careful before they haul horses to racetracks, sales, shows, and breeding farms. New arrivals on breeding farms must be isolated at least 3 weeks before coming into contact with any other horses, but especially mares in foal.”

Although a vaccine exists to protect against EVA, the outbreak has caused a severe shortage. No doses will be available until October, according to Rocky Bigbie, DVM, MS, director of field veterinary services for Fort Dodge Animal Health, the vaccine manufacturer.

New Mexico Deputy State Veterinarian Dave Fly, DVM, said veterinarians within that state are not writing health certificates more than 7 days before they will be needed for general hauling, and no more than 48 hours before the horse goes to a track. No other states have imposed restrictions at this time.

Kentucky has not imposed any restrictions, but Rusty Ford of the Kentucky State Veterinarian's office says they are taking special interest in horses coming from affected states.

EVA is a contagious viral equine disease that closed the breeding industry in Kentucky in 1984. Some of the clinical signs associated with EVA are fever, respiratory illness, ocular inflammation, dependent edema (swelling), pneumonia or pneumonia enteritis in foals, and abortion. The virus can be spread through semen in the case of an acutely infected stallion, infected respiratory secretions, or indirectly through shared breeding shed equipment or tack.

Stallion owners are urged to test their stallions and vaccinate as soon as the vaccine becomes available. Seropositive shedding, or carrier, stallions should be managed separately from nonshedding seropositive and seronegative stallions, and semen from all seropositive stallions should be tested to ensure they are not carriers.

Reprinted with permission of The Horse; visit www.TheHorse.com for more horse health news.