Colic, cocaine positives in post-race testing, reinforcement breeding to enhance fertility among topics discussed

by Denise Steffanus

THE LARGEST crowd in the 52-year history of the annual convention of the American Association of Equine Practitioners turned out for this year's event in San Antonio on December 2-6, when 4,477 veterinarians, students, technicians, and guests, plus 2,313 exhibitors met to share knowledge in the Alamo City, which hosted the event for the second time in seven years. In 2000, San Antonio also drew a record crowd.

In his opening remarks, AAEP President-elect Douglas Corey, D.V.M., said, "Equine veterinary medicine was very much in the spotlight in 2006, and it was all very positive for our profession. Not only were the advances in equine medicine highlighted this year, but also the dedication of men and women who are known as 'the horse doctors.' "

Corey told listeners the goal of this year's convention would be to present practical information and instruction that could be taken to their home practices. Another key goal, he said, was to help veterinary students succeed. To accomplish this, Corey asked seasoned practitioners to mentor young veterinarians, who by his estimate were about a quarter of the members attending the convention.

Racing Hall of Fame trainer D. Wayne Lukas kicked off this year's convention with a keynote speech in which he spoke about how he had come from a one-room-schoolhouse education in Wisconsin to his current success through simplicity, discipline, and dedication.

"We have found that in training horses and winning races--whether it's performance horses, Quarter Horses, or Thoroughbreds, it

doesn't make any difference--if you will do the common things uncommonly well, you will be successful," Lukas said, adding that those common things include good feed, correct angle on the feet, hair coat that reflects good care, and deep bedding.

Lukas said the right approach also is important.

"Find out what you want to do [with a particular horse] and then start focusing and get clearly on the target," he said.

The trainer offered other practical advice, including not crossing the fine line between training for peak athletic fitness and overtraining to the point when the horse becomes stale; eliminating tension in the horse's environment by not asking it to do what it has not been prepared for or is incapable of doing; not being afraid to lose, because losing causes one to self-evaluate; not just having a dream but making a commitment to accomplish that dream; and not underestimating the power of kindness.

Milne Lecture on colic

Nathaniel White II, D.V.M., M.S., director of the Marion duPont Scott Equine Medical Center at the Virginia-Maryland Regional College of Veterinary Medicine, presented this year's Frank J. Milne State-of-the-Art Lecture. White, a board-certified veterinary surgeon who helped to establish the annual Equine Colic Research Symposium, outlined advances in diagnosing and treating colic and emphasized the need for owner education as a key preventive measure.

White cited certain risk factors for colic as common among horses, including:

•a diet that contains coarse roughage with low digestibility;

•lack of access to water;

•poor dentition;

•changes in environment, such as sudden curtailment of activity when a horse is confined to cope with an injury or recover from surgery;

•certain management practices, such as feeding horses grain after bringing them in from pasture and then confining them in stalls for part of the day;

•parasites; and

•cribbing, which recently has been shown to create an increased risk for entrapment of the small intestine due to the negative pressure created in the abdomen by aerophagia or wind sucking.

"While colic may affect horses of any breed, several studies suggest an increased incidence of disease in Arabian or Thoroughbred horses," he said.

White said researchers have been experimenting with different types and techniques of superhydration to resolve impaction colics, and more clinicians are employing solutions administered by nasogastric tube rather than administering volumes of intravenous fluids.

He advocated the use of a balanced electrolyte solution containing three teaspoons of salt, one teaspoon of Lite Salt (a salt and potassium chloride mixture), and four teaspoons of baking soda per each five liters of tap water. The solution is delivered in a controlled flow via nasogastric feeding tube at a rate of five to ten liters per hour.

"What we have done is sometimes administer it chronically," White said. "We put a feeding tube down through the nose and we just pour it in at a rate to try to get it in without overloading the stomach all at once."

Owner education is paramount to prevention of colic, White said.

"Based on these known factors, colic prevention should start by making sure horses have a constant source of fresh water, ensuring that forage makes up at least 60% or more of the diet, and that concentrates [soluble carbohydrates] are fed at the minimal level required to maintain weight and performance," he said. "The turn-out and exercise routines should be regular and consistent. Changes in feed should be completed over a seven- to ten-day period. Parasite control must be optimal."

With resistant strains of parasites emerging, White suggests that horsemen adopt a program that is based on assays of fecal egg counts several times during the year and more often in horses that are moved in and out of farms and stables.

In another topic on gut health, Sarah le Jeune, D.V.M., and her colleagues at the University of California at Davis studied 62 Thoroughbred broodmares at pasture to determine if pregnant mares were more prone to gastric ulcers than those that were not in foal.

Study results indicated that pregnancy was not a factor in development of ulcers, but the researchers found that broodmares at pasture have a higher incidence of gastric ulcers than previously suspected. Of the 33 pregnant mares and 29 barren mares studied, 22 in each group (44 individuals or 71% total) were found to have gastric ulcers.

Environmental contaminant

Roberta Dwyer, D.V.M., M.S., of the University of Kentucky's Maxwell H. Gluck Equine Research Center, began her presentation by asking listeners to take out a dollar bill and rub it between their hands.

"Cocaine is an environmental contaminant; it's also an illegal drug ... which is on 80% of your hands right now," said Dwyer, who was making the presentation on the presence of a metabolite of cocaine in post-race tests on behalf of absent Gluck researcher Fernanda Camargo, D.V.M.

Dwyer explained that in drug testing in the human workplace, the metabolite, benzoylecgonine (BZE), is recognized as an environmental contaminant and typically is considered a negative finding when it appears at levels below 300 nanograms per milliliter of urine.

"In horses, a cocaine dosage of one milligram per horse yields less than a 100 nanograms per milliliter urinary concentration," she said. "One milligram produces no pharmacological effects, such as performance or anesthetic effects.

"Cocaine introduced directly into horse urine hydrolyzes into BZE," she said. "That would be in an example of where a negative horse had a urine sample collected and there was some accidental contamination after the urine was collected."

During the study, Camargo and her associates tested 136 dollar bills; 79% of them tested positive for BZE and 50% of them contained 1,000 nanograms or more per bill.

"One of those bills [from Portsmouth, Ohio] had 1.3 milligrams of cocaine on it," Dwyer said.

Screening tests for cocaine can detect concentrations of BZE as low as one-half nanogram per milliliter, she said.

"When ELISA [enzyme-linked immunosorbent assay] tests for cocaine first became available and were introduced in California in 1989, a considerable number of horses were called positive with very low levels of BZE urinary concentrations," Dwyer said. "Many of these horses had reputable and very respected trainers, and it caused quite a bit of stir for obvious reasons."

A horse can be exposed to BZE when a human with contaminated hands touches the horse's muzzle, handles its bit or tongue tie, or hand-feeds the animal.

"Exposure of a horse to amounts of cocaine found on dollar bills usually triggers a BZE identification," she said.

The study reported that from 2000 to '05, racing jurisdictions found 52 positive cases of BZE in post-race tests.

Several racing jurisdictions in the United States have adopted cutoff levels comparable to those used in human-workplace urine testing. This protocol suggests that racing officials have begun to recognize BZE as an environmental contaminant, Dwyer said.

To cope with this problem, the National Horsemen's Benevolent and Protective Association's "Proposed Policy for Drug Testing and Therapeutic Medication" advocates a cutoff of 150 nanograms per milliliter of BZE in urine.

Reinforcement breeding

Reinforcement breeding is the practice of collecting semen from the exterior of the penis when the stallion dismounts the mare and then mixing it with prewarmed semen extender and infusing it into the uterus of the mare just covered.

Terry Blanchard, D.V.M., M.S., theriogenologist of the year and resident veterinarian at John G. Sikura's Hill 'n' Dale Farms in Lexington, reported: "Mares receiving reinforcement breeding had a greater chance of getting pregnant than mares that were not reinforced; this resulted in an average increase of a 12%-per-cycle pregnancy rate in eight of 13 stallions in the study."

Blanchard said stallions whose impregnation rates increased with the use of reinforcement breeding during the first season it was used also experienced a similar increase when it was used in subsequent years. Some stallions, however, did not benefit from reinforcement breeding.

For mares with endometritis or other conditions that may be hostile to sperm, Blanchard said use of semen extender containing antibiotics might suppress the bacteria and allow the sperm to live long enough to impregnate the mare, thus increasing fertility.

Tough act to follow

Since its inception in 1998, the Kester News Hour, which annually offers a fast-paced and often hilarious look at thought-provoking topics over the preceding year, has been hosted by John Madigan, D.V.M., M.S., of the University of California at Davis and Larry Bramlage, D.V.M., M.S., chief of surgery at Rood & Riddle Equine Hospital in Lexington.

This year's Kester News Hour was announced as the last appearance for Madigan and Bramlage. AAEP officials now have the task of finding successors for the popular duo, whose jab-and-parry style has made the Kester News Hour a perennial favorite among convention attendees.

For their efforts over the years in presenting news in an entertaining and impressionable fashion, Madigan and Bramlage were presented with the AAEP Distinguished Service Award, which recognizes exemplary service to the AAEP or a similar organization to benefit the horse, the horse industry, or equine veterinary medicine.

Also recognized with a Distinguished Service Award was Claude Ragle, D.V.M., associate professor of clinical sciences at Washington State University. Ragle founded and moderates the "Equine Clinicians Network," an online forum to discuss and share information related to equine medicine and surgery.

Thomas Divers, D.V.M., professor of medicine and chief of large animal medicine at Cornell University's College of Veterinary Medicine, was honored as this year's distinguished educator.

Other honors went to AAEP Past Presidents J. Clyde Johnson, V.M.D., and Charles Vail, D.V.M., who received Distinguished Life Member awards for their contributions to veterinary medicine and the AAEP.

Denise Steffanus is a contributing editor of Thoroughbred Times who writes frequently on veterinary and farm management topics.