Horseman's Day at the 2002 AAEP Convention
Horseman’s Day, held for the third time as part of the annual AAEP convention, was another rousing success. There weren’t as many people in attendance as there were in San Diego last year, but they were just as enthusiastic. AAEP officials said that 266 were in attendance at the Orlando session compared to 400-plus last year and about 200 when the event was held for the first time in San Antonio. Perhaps a better way to assess the success of such an event is the enthusiasm and interest demonstrated by the attendees. With that as criteria, Horseman’s Day 2002 passed with flying colors.
Helping stimulate the interest and enthusiasm shown was the quality of the speakers. They couched their talks in terms the average horse owner could understand, but they certainly didn’t talk down to them. The horse enthusiasts in attendance demonstrated their interest with a barrage of questions at the end of each presentation.
Following is a brief report on each presentation:
Equine Emerging Diseases
Leading off the program was Maureen Long, DVM, PhD, of the University of Florida College of Veterinary Medicine, Dept. of Large Animal Clinical Services, who was standing in for Genevieve Fontaine, DVM, MS, Dipl. ACVIM, assistant professor at the University of Florida, who had been scheduled to give the talk, but was unable to be there. The prime focus of the talk was West Nile virus (WNV).
She started with a brief history of the disease, pointing out that it was first identified in 1999 in New York. From there it has spread west across the United States and into Canada.
As of convention week (Dec. 4-8, 2002), Long said, there were 13,600 confirmed equine cases for the year, with the heaviest hit area being the Midwest. Because many of the attendees were from Florida, she outlined the progress of the disease in that state. Thus far in 2002, Long said, there had been 463 confirmed equine cases in 44 Florida counties. There have been 28 human cases in Florida for the year (updated through Dec. 13).
Of the 463 equine cases in Florida, Long said, 254 of the horses had not been vaccinated. For another 102, information on vaccination was not available. Of those known to have been vaccinated and still contracted the disease, 67 had received one injection instead of the recommended two; 29 had received two injections, and 15 had received three injections.
There are about 250,000 horses in Florida, Long said, and only 30-40% have been vaccinated.
The proper protocol for vaccination, she said, is for the first injection to be given well before the onset of mosquito season and the second one to follow in three to six weeks. From that point on, the ideal approach is to give a booster injection every three to four months during the peak of mosquito season.
Acknowledging that such an approach could be costly if one had a large number of horses, the minimum that should be done was to give the two injections and follow up with whatever boosters the horse owner deemed affordable.
Long recommended that foals be given their first injection at three to four months of age, but pointed out that they need three booster shots before the vaccine is effective. She said that the vaccine is not labeled as being recommended for broodmares, but that it has been administered to them with no untoward negative effects.
Treatment of the affliction can be expensive, Long said, with the average hospital stay being 10 days and the average cost running at about $1,700 per horse, with some being as high as $4,000. If the horse survives, she said, the recovery time can vary from one to 12 months.
"I’d like to say that we have some great treatment out there for West Nile," Long said, "but we don’t."
The treatment approach used is strictly supportive, she said, and can involve administering banamine, DMSO, and hyperimmune plasma from heavily vaccinated horses.
Long also described the clinical symptoms, which include twitching, depression, increased body temperature, spinal cord disease, and paralysis.
She urged horse owners to take preventive measures by clearing up mosquito breeding areas, using insect repellent on horses, putting screens over stable windows, and attempting to keep horses out of areas that are heavily infested with mosquitoes.
Also discussed was mare reproductive loss syndrome (MRLS), which struck with savagery primarily in Kentucky in 2001 and to a lesser degree in 2002. It is estimated, Long said, that during 2001, the loss of foals through early fetal loss and abortion was somewhere between 4,000 and 5,000. Blame for the malady has been laid at the door of the Eastern tent caterpillar, which was present in great numbers during that time frame.
Although MRLS is still a problem, she said, the loss rate has lessened during the past year. As of convention time, she said, about 500 early fetal losses and 165 abortions had been reported.
Controlling the population of Eastern tent caterpillars and preventing horses from ingesting them are the prime preventive measures.
Equine Gastric Ulcer Syndrome
Frank Andrews, DVM, MS, Dipl. ACVIM, professor of equine medicine at the University of Tennessee, gave the presentation equine gastric ulcer syndrome, which carries the acronym (EGUS). Ulcer problems are widespread in the horse population, he told the group, with 25-50% of all foals suffering from the affliction along with 60-93% of adult horses. Reaching the 93% mark, he said, are horses involved in racing or race training. In one study, Andrews said, it was found that 100% of the racehorses involved were suffering from ulcers.
Andrews said about 92% of clinically ill horses have been found to also be suffering from ulcers.
Andrews explained that the horse’s stomach is divided into two distinct regions--the esophageal or non-glandular region and the glandular region. The non-glandular region, or squamous mucosa, involves about one-third of the stomach, he said, and is devoid of glands. It is covered by stratified squamous epithelium similar to the esophagus. The remaining two-thirds of the stomach is the glandular region that contains glands, which secrete hydrochloric acid, pepsin, bicarbonate, and mucus. A sharp demarcation line known as the margo plicatus or cuticular ridge separates the two regions.
Ulcers in the squamous mucosa region, he said, are primarily due to prolonged exposure to hydrochloric acid, pepsin, bile acids, or organic acids. The squamous mucosa near the margo plicatus is constantly exposed to these acids, and this region is where gastric ulcers are frequently found in foals and horses because there is little or no natural protection against the acids.
Ulcers in the larger portion of the stomach--the glandular region--are primarily due to disruption of blood flow and decreased mucus and bicarbonate secretion.
"Horses out on pasture rarely have ulcers," Andrews said, because they are eating almost constantly and the presence of food has a buffering effect on stomach acids. "Proper feeding is the best way to prevent ulcers," he said.
Proper feeding in his terminology means providing the horse with a constant source of grass or hay. It has been found that alfalfa hay can help to prevent ulcers because it normally is high in protein and calcium, and they tend to neutralize the acid produced in the stomach.
"Feeding alfalfa hay to a horse is a bit like a human taking an antacid," he said.
Conversely, he said, a diet high in grain results in heavy production of acid. Stall confinement, he added, also often results in more acid production and a higher ulcer rate. Physical and behavioral stress also are implicated.
Clinical signs of ulcers in adult horses, Andrews said, include poor appetite, poor body condition, changes in attitude (from friendly to sour disposition), a decrease in performance, and, sometimes, mild to moderate colic. In the foal, he said, the clinical signs often include a grinding of teeth and lying down on the back after eating.
The only definitive way to diagnose ulcers, Andrews said, is by examining the stomach with a long endoscope.
Treating a horse with ulcers is a good news/bad news scenario. The good news is that omeprazole, marketed as GastroGard, will effectively clear up ulcers in most horses and even prevent them if the horse is kept on the medication. The bad news is that GastroGard is expensive. Treating a horse with the medication once per day as recommended in the early stages can cost in the neighborhood of $500 per month. Sometimes a half-dose is given as a preventive measure, once the ulcers have been cleared up.
New Reproductive Technologies
Michelle LeBlanc, DVM, Dipl. ACT, of Rood and Riddle Equine Hospital in Lexington, Ky., also presented something of a good news/bad news scenario in the use of new reproductive technologies in breeding programs.
The good news, she said, is that advanced reproductive technologies--such as cooled semen, frozen semen, embryo transfer, and gamete inter fallopian tube transfer (GIFT)--have given horse owners choices and freedom. The bad news is that there is higher price tag attached.
"Two things increase with new technologies--expertise and cost," LeBlanc said.
One of the most expensive methods to achieve a pregnancy, she said, is the GIFT approach, which involves taking an egg from an infertile mare, fertilizing it, then implanting it into another mare. The procedure, she told her listeners, could cost between $20,000 and $25,000, with pregnancy rates having risen to about 30% for a given breeding season.
Embryo transfer also can be expensive, she said. An embryo transfer foal at weaning time, she said, must carry a value of $10,000 to $12,000 if the owner is to break even.
Improved techniques in handling and shipping cooled semen, LeBlanc said, has resulted in pregnancy rates being about equal to natural cover, providing the semen is used within 24 hours after being collected. When that is the case, she told the group, pregnancy rates will range between 60-80%, the same as for live cover.
However, if cooled for 48 hours, the semen will result in a pregnancy rate that is cut in half. Most stallions will have a pretty good sperm survival rate for 36 hours, she said, but it declines rapidly after that. However, LeBlanc added, in the case of some warmbloods, semen has been known to survive for 72 hours.
There are more costs when inseminating with cooled semen, she said, because management is more intense, involving such items as frequent ultrasound examinations and the cost of shipping semen.
It is important for the mare owner to know, LeBlanc said, that not all stallions’ semen ships well. Some have a high sperm survival rate when semen is cooled and shipped, and others do not. It behooves the horse owner to find out if the stallion he or she plans to breed to is a "good shipper."
When the sperm arrives for insemination, at least 30% of them should be progressively motile, which means they are moving in straight lines and not in circles, she said. Those live, progressively motile sperm should number at least 500,000.
She said the mare owner also should learn all of the details about shipment of semen, such as whether the stallion is collected every day or every other day and how many shipments will be sent before the mare owner is assessed an additional charge.
When semen is frozen and then inseminated, she said, pregnancy rates decline. "The more we manipulate the semen, the lower the pregnancy rate."
Only about 40% of the stallions in this country freeze well, LeBlanc said, and pregnancy rates on the average range from 35-40% with frozen semen. Pregnancy rates are higher for young mares than for older ones, she said.
A major assist it obtaining pregnancies with both cooled and frozen semen has been the development of the hormonal drug Ovuplant. When ovuplant is implanted beneath the skin of the neck or in the lining of the vulva, it insures a predictable ovulation providing the follicle is at the proper stage of maturity. Much the same effect can be achieved with human chorionic gonadatropin (hCG), which has been around for a long time, she said, However, Ovuplant is more specific for ovulation time and often is her treatment of choice when using frozen semen.
There also is a difference in cost, she said, with hCH costing in the $18-$25 range and Ovuplant at $50-$60 per treatment.
The most important elements when dealing with transported semen, LeBlanc said, are communication, coordination, and cooperation among all parties involved.
Stephen O’Grady, BVSc, MRCVS, of Northern Virginia Equine, provided the presentation on Proper Physiological Horseshoeing.
"Physiological horseshoeing," he said, "means, let’s get back to the basics. There may be no other routine procedure performed on a horse that has more influence on soundness than hoof preparation and shoeing. While methods may vary, the basic objectives when trimming and shoeing are to facilitate breakover, protect the sole, and provide adequate heel support.
Breakover, O’Grady explained, is that phase of the stride between the time the horse’s heel lifts off the ground and the time the toe is lifted. During this phase, he said, the toe acts as a pivot point (fulcrum) around which the heel rotates.
Breakover can be significantly delayed, he said, when the horse has a long toe and low hoof angle--the angle between the front of the hoof wall and the ground surface. In that case, he explained, the toe acts as a long lever arm, requiring more time and effort to rotate the heel around the toe.
Shortening the lever arm, O’Grady said, facilitates breakover. "Depending on the horse, facilitating breakover may involve trimming the foot to decrease toe length and/or applying a rolled-toe, rockered toe, or square toed shoe."
The prime function of the sole, O’Grady said, is to protect and support the underlying structures, particularly the coffin bone and the network of blood vessels that supply the sole and wall. To function properly, he said, the sole must be concave and firm to thumb pressure.
"Inadequate sole depth," he said, "is the most common cause of chronic sole bruising. Sole depth can be maintained simply by trimming the hoof wall appropriately and removing very little, if any, sole at each trimming."
O’Grady then switched to a discussion of heel support. It is important to provide heel support, he said, because of the great forces placed on the heels when landing after going over a jump and during weight-bearing phases of the stride. Landing after a jump, he said, can put up to 3,000 pounds of pressure on a foot. Abnormal hoof-pastern axis (such as the broken back hoof-pastern axis) greatly contributes to overloading of the heels which can cause chronic bruising and shearing of the hoof wall, along with chronic heel pain.
For years, he told the group, horsemen thought hoof angles should range from 48 to 55 degrees in front and 52 to 60 degrees behind. However, he said, that has been found to be erroneous.
The correct angle, he maintained, occurs when the hoof-pastern axis is in alignment.
"A normal hoof-pastern axis," he said, "is one in which a line drawn along the front of the hoof wall is parallel to the pastern. In this situation, each of the bones of the digit--P1, P2, and P3 (the proximal, middle, and distal phalanx, respectively)--is in normal alignment."
A broken-back axis is created by a low hoof angle where the angle of the hoof wall is lower than the pastern angle. This condition, O’Grady said, contributes to navicular syndrome, chronic heel pain, coffin joint inflammation, quarter and heel cracks, interference during motion, and delayed breakover.
This configuration, he said, often is caused by the long toe-underrun heel conformation.
The opposite problem is a broken-forward hoof-pastern axis where the angle of the hoof wall is higher than the angle of the pastern. This abnormality, sometimes referred to as clubfoot, also contributes to coffin joint inflammation and pain in the navicular area as well as sole bruising.
"In addition to trimming the hoof to normalize the hoof-pastern axis," O’Grady explained, "it is important that the weight-bearing surface of the wall extend as far back as possible. Ideally, an imaginary line dropped down from the center of the cannon bone should land right where the heel ends, not well behind the heels as is often the case. If the heel cannot be trimmed to provide optimal support at the back of the foot, the branches of the shoe can be extended to compensate and optimize the bearing surface area."
Jack Snyder, DVM, PhD, Dipl. ACVS, University of California, Davis, tackled the broad topic of colic, which is still the number one cause of death in horses. In general, he said, colic is defined as anything that causes abdominal pain, but the majority of the time, acute colic is associated with a problem of the intestinal tract.
Non-intestinal causes of colic, he said, can include tying-up, laminitis, pneumonia/pleuritis, uterine twist, heart failure, urinary stones, and ruptured bladder in foals, to name a few.
All types and breeds of horses experience colic, he said, although there are some types that seem to afflict specific breeds more often. For example, he said, Arabians seem to have a higher incidence of enteroliths or intestinal stones than other breeds. The geographic area can also be implicated. For example, California and Florida have more problems with enteroliths than other states.
There are classic signs of colic, Snyder said, such as rolling and pawing. Other signs include looking back at the flanks, lying down longer than normal, sweating, and signs of depression. Horse owners should be aware that older horses tend not to show pain to the same degree as young horses. And, he added to the delight of the female attendees, males tend to show more pain than females.
Snyder then described the gastrointestinal anatomy. He commented that no plumber would ever come up with such a design because there are areas where a large opening empties into a smaller one and other areas where the material passing through the tract must make a sharp turn, all of which can set the stage for digestive problems and colic.
His take home message was that horse owners should have a plan in place in case colic strikes. The plan should address the following:
- Determine ahead of time which horses would be considered for surgery.
- Determine how much money you are prepared to spend.
- Have a transport plan and decide where the horse will be taken if surgery is an option.
- Determine who is to make decisions if the owner is not available.
- Inform the veterinarian of the insurance status of each horse.
If the horse colics, he said, the owner should remove all food, notify the veterinarian, keep the horse as calm and comfortable as possible, and if the horse is rolling or behaving violently, an attempt should be made to walk it slowly. It is okay for the horse to roll, he said, providing that rolling doesn’t endanger the handler or the horse.
The best way to prevent colic, Snyder said, is to provide the horse with a constant source of fresh water, maintain at least 60% of the diet as forage, avoid rapid changes in feed, have a good de-worming program, maintain proper dental care, minimize transport stress, and watch horses more closely during wide changes in temperature or episodes of violent weather, he said.
In areas where enteroliths are common, he said, alfalfa is sometimes implicated. Two types of hay should be fed, with no more than 50% being alfalfa. An enterolith is formed from magenesium ammonium phosphate, and alfalfa hay in California often is high the minerals that comprise an enterolith.
Bits, Bitting, and Dentistry
R. Dean Scoggins, DVM, from the University of Illinois, was the final presenter. His topic covered bitting and dentistry practices to ensure that the bit is fitted properly to the horse’s mouth.
"Correctly bitting a horse has very little to do with mechanics," he said. "It has everything to do with feel, timing, and balance. It is much more an art form than a science. In the hands of some individuals, a complex high-port curb bit is an instrument of communication with all the delicacy of playing a violin. In another person’s hands, a thick hollow-mouthed snaffle may be as dangerous as a surgical scalpel in the hands of a monkey."
The first consideration in placing a bit in a horse’s mouth, Scoggins said, is to be sure there are no abnormalities within the mouth that could cause discomfort. Old injuries, such as scars, sharp or abnormally located teeth, misshapen jaws, or previous tongue injuries, should all be noted and the necessary corrections made.
"Many trainers are having their veterinarians do a ‘performance float’ of their horses’ teeth before introducing the horse to the bit,” said Scoggins. “They remove all sharp edges plus rounding the front corners of the first cheek teeth, both upper and lower. This allows more room for mouth tissues and reduces discomfort when the reins are tightened and bit pressure increased. Wolf teeth and mature caps are also removed as needed. Properly performed dental work is often credited with putting ‘power steering’ on a horse that previously had difficulty wearing or accepting the bit."
Scoggins described and showed slides of a wide variety of bits and explained the type of pressure that each exerted.
About the Author
Les Sellnow is a free-lance writer based near Riverton, Wyo. He specializes in articles on equine research, and operates a ranch where he raises horses and livestock. He has authored several fiction and non-fiction books, including Understanding Equine Lameness and Understanding The Young Horse, published by Eclipse Press and available at www.exclusivelyequine.com or by calling 800/582-5604.
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