100 Years of Horse Health Care
Standing on the fresh field of a brand new century, we look eagerly-if sometimes cautiously-toward the horizon and the unknown future awaiting us. We hope that, in the months and years to come, we will solve problems long puzzled over and finish battles long fought. We look, in short, at all that is left to do, all that we have yet to accomplish.
But before we take up our loads for the work ahead, let's take time to appreciate just how far we've already come. Let's gaze backward for a time and smile with satisfaction at the incredible feats accomplished in the past 100 years. What better place for a horse lover to look than at the world of equine health care…
In The Beginning
One hundred years ago, most of America's horses were revered not for their ability to jump or race or for their sheer beauty, but for their truly utilitarian horse power. They were beasts of burden-and they were as important and integral to human life as were the sun and rain. As such, horses were populous, and their good health essential.
In 1905, there were 17 million horses in the country, says Henry Heymering, CJF, RMF, president of the Guild of Professional Farriers. By 1915, the equine population had surpassed 20 million. Those early years of the century were the horse's heyday. While techniques and tools were certainly primitive by today's standards, the vital importance of equine care was never questioned: Understanding horse health was mandatory for every farmer and veterinarian in the country.
Then came the industrial revolution and the combustion engine. Automated ma-chines, from cars to tractors, took over the horse's central role. Equine populations declined. By 1960, numbers had dropped dramatically, to between one and three million (depending on the source).
The horse's importance in the eyes of the veterinary community had similarly diminished. Marvin Beeman, DVM, a practitioner at the Littleton Large Animal Clinic in Littleton, Colo., and a former president of the American Association of Equine Practitioners (AAEP), attended vet school in the late 1950s. "At that time, people thought the horse would disappear," he recalls. "In my class at vet school, I was the only one planning to be an equine practitioner."
Even as numbers hit rock bottom, the ownership of horses gradually began a turnaround. No longer needed as beasts of burden, they took on a whole new role, one that Morris Animal Foundation officially recognized in 1960: companion animal.
"Horses were coming away from the farms, being boarded, and becoming pets," says Robert Hilsenroth, DVM, executive director of Morris Animal Foundation. "Their value changed from one of horsepower to one of love or companion power."
In this new position of pal and performer, horses have experienced a resurgence in importance and numbers. The American equine population, while never regaining the high status experienced in the early 1900s, has edged back up to roughly seven million members today.
Similarly, quality equine health care once again rests comfortably high on the priority list of the veterinary and research communities. Even more exciting, some aspects of equine care and study now are impacting human health, bringing additional attention and resources to our industry. In other words, we've come a long way, and we're still on a roll. To prove it, we present here an overview of where we've been, what we've achieved, and where we'll go from here.
Most modern horse owners take preventive care for granted. Not so the owners of yesteryear. "[Prevention] has caught on in horses more slowly than in poultry, dairy, or other production animals," says Albert J. Kane, DVM, MPVM, PhD, postdoctoral fellow at Colorado State University. "It used to be that we focused just on treating sick horses. If the horse was healthy, we (vets) didn't see it."
Now, he continues, we pay attention to every possible aspect of preventive care, from manure management and nutrition to dental care, regular deworming, and routine vaccinations. In addition, research projects no longer focus primarily on treatments and cures, but on methods of prevention and risk analysis for everything from infectious disease to injury.
Few question that this elemental change in the perception of preventive care has had a major impact on improving horse health. Few would argue that deworming ranks among the most beneficial preventive measures now practiced-one that has changed dramatically since the dawn of the 20th Century.
Until the 1960s, potent chemicals such as carbon disulfide were the veterinarian's best offense against internal parasites. Defense wasn't even considered.
"My dad was a vet in the 1920s," says Harold Drudge, PhD, a parasitology specialist, Professor Emeritus at the University of Kentucky, and member of the Research Hall of Fame. "Back then, they only wormed the horse if there was a problem."
Of course by the time trouble was apparent, the horse generally hosted a large contingent of internal parasites. To have any effect whatsoever at that point, the deworming chemicals had to be given in large doses, which sometimes proved more lethal than the worms themselves. Being similarly potent in smell and taste, the medications hardly presented an enticing treat for the horses. Thus, veterinarians relied on drenching and tubing to get treatment into the animal. These tactics were no fun for horse or practitioner.
Recalls Drudge, "When Dad needed to drench a horse, he'd back it into a slip stall. Then he'd take a rope, put it over the horse's upper incisors, and loop it over a ceiling joyce. He'd pull on the rope to elevate the horse's head just a bit above level, then pour the liquid down its throat."
Progress has come slowly, and in small steps. The first notable deworming advancement of the 1900s probably didn't arrive until 1940, with the introduction of phenothiazine as a weapon against large strongyles, says Drudge.
By the late 1940s, practitioners were using low-level phenothiazine in the horse's daily grain ration. That was, perhaps, the first step toward the notion of preventive deworming and was the precursor to such modern-day feed-through wormers as Strongid-C (a pyrantal-based product).
In the early 1950s, piperazine was added to the arsenal, helping to battle ascarids and small strongyles. Researchers soon discovered that "phenothiazine given with piperazine had a synergistic effect," says Drudge. "We learned that if we repeatedly gave that mixture at intervals, we could sleep at night without worrying about losing foals and horses to strongyles."
Later in the 1950s, Upjohn introduced Parvex Plus, which, says Drudge, "became the drug of choice against bots for years." Interestingly, the product was based on a chemical mixture that included modern piperazine with old-fashioned carbon disulfide. "It was a subtle way of giving carbon disulfide, because the acid wasn't released until it reached the horse's stomach," he explains.
In the 1960s, the benzimidazoles became available and, in 1963, continues Drudge, "Thiabendazole became the best thing yet down the pike. Merck was so excited about it. We all were. It would just clobber those blood worms."
About that time, the notion of rotating dewormers became feasible. "For a long time, we only had one thing that worked," says Drudge, "but as more products became available, we started advocating rotation."
The reasoning behind rotation, he continues, was in part to battle resistance, but also for fear that if a product wasn't used enough, it would be taken off the market. (Today, that has become a reality, he says, as certain products, such as phenothiazine, are either off the market or very difficult to find.)
Paste wormers revolutionized deworming in the late 1970s. They gave a huge push to the promotion and popularization of preventive worming, for the first time allowing horse owners to treat their animals without a veterinarian's assistance.
The 1980s also brought us the first product proven effective against a broad range of internal parasites-ivermectin. Soon available in handy paste form, this all-around wormer broke the tradition of rotation by claiming-and proving to most equestrians' satisfaction-not only to eliminate most major worms, but to do so without creating resistance.
Today, there is no doubt that horses, owners, and veterinary practitioners benefit from the ease and effectiveness of modern deworming agents-and the now commonplace notion of preventive deworming programs.
It's not fair to say that yesterday's equestrians weren't interested in disease prevention; they simply didn't have the tools to make it happen. Often, quarantines and post-infection treatments were the only ways to manage disease.
Luckily, throughout this century, "there has been a steady progression of improved knowledge of infectious diseases and the means to prevent and treat them," says Ghery D. Pettit, DVM, retired professor of surgery at Washington State University's College of Veterinary Medicine. Today, with vaccines in hand and greater knowledge in our heads, we can prevent numerous diseases, and save a huge number of horses.
During the century's first two decades, for instance, thousands of horses succumbed to equine encephalitis, until a vaccine against it was introduced in the late 1920s. Since that breakthrough, many other vaccines have been created to control equine diseases, including herpes viral abortion, equine viral arteritis, strangles, equine influenza, Potomac horse fever, streptococcus, tetanus, rhinopneumonitis, and shaker foal syndrome (botulism). All of these vaccines were created within this century, and many were developed only within the past 50 years.
As Robert K. Shideler, DVM, Professor Emeritus of Clinical Sciences at Colorado State University's College of Veterinary Medicine and Biological Sciences, says, "The making of vaccines has become a highly complicated field, down to the level of DNA and genetics."
Indeed, that's true not just of vaccines, but of the entire field of disease control. Collaborative efforts among a number of universities, for example, determined that fatal combined immunodeficiency disease (CID) in Arabian horses was genetically transferred. By 1997, investigators had identified the defective gene marker and chromosomal location of the CID gene and developed a test to detect CID carriers.
The technology and advanced knowledge that allow scientists to work at these microscopic levels also is increasing the pace of discovery. For instance, says Beeman, researchers this decade solved a mystery in the Quarter Horse industry. Animals of all ages and genders had been succumbing by the dozens to an unknown and debilitating ailment. Within just seven years, researchers identified the disease, dubbed it hyperkalemic periodic paralysis (HYPP), determined it was an inherited trait, pinpointed the dominant gene that causes it, and created a DNA test to spot the disease and detect its carriers.
The concept of disease testing itself has grown this century. In the early 1960s, Leroy Coggins developed what we now commonly call the Coggins test, which detects the presence of equine infectious anemia. By detecting horses infected with this contagious disease-for which there still is no cure-veterinarians and horse owners now can contain the disease, preventing potentially epidemic spreads.
Similarly, the University of Kentucky developed a blood test to detect evidence of contagious equine metritis infection (CEM) in mares. UK also, within the past five years, created a diagnostic test using spinal fluid in live horses to detect one of our horses' newest enemies-equine protozoal myeloencephalitis (EPM). Methods for diagnosing (and treating) such ailments as periodic ophthalmia, wobbler syndrome, and hemolytic jaundice of newborn foals also have evolved during the 20th Century.
However, the battle is by no means won. With diseases such as EIA, EPM, and vesicular stomatitis still at large and without vaccines, much work remains. In fact, this almost certainly will be an eternal fight. Says Morris Animal Foundation's Hilsenroth, "We are dealing with biological systems. By their very nature, there will always be new diseases and new conditions. Bacterias become resistant; new pathogens are discovered. It's a very dynamic situation."
In some cases, of course, prevention isn't applicable. In those cases, diagnosing a problem becomes a vital step in helping the horse. One of the most important diagnostic tools-not only of today, but of yesterday, as well-is the X ray machine. Without it, and the host of other helpful diagnostic tools that have come along more recently, we would be left to determine the roots of many subcutaneous ailments simply with look and touch.
Not a 20th Century achievement, the X ray was discovered in 1895. A year later, the first radiograph was taken-ironically, of a horse's leg-even though the technology was initially used in human medicine. In fact, these first, primitive X ray machines "were not much use (to equine vets) except for the foot and lower leg," says J. Fred Smithcors, DVM, PhD, a retired Michigan State University professor. "We X rayed a few feet, but that was about it."
Improved machines and parts (like plates and film) developed within the past two decades have made X rays a true diagnostic asset for the equine practitioner, useful-and used-on numerous body parts.
The past 20 to 30 years, in fact, have been a period of most dramatic advancement in equine diagnostics. In the early 1970s, says Beeman, the advent of lidocaine and other improved local anesthetics-plus disposable plastic syringes and disposable needles-made diagnostic blocking increasingly effective, allowing vets to pinpoint more precisely the location of a lameness. Previously, practitioners had relied on procaine, a highly irritating local anesthetic. "We never dared put it inside a joint, so joint lamenesses went undetected," Beeman says. "With good blocking agents, we went from thinking a horse was, for instance, lame in the shoulder, to realizing that he was lame in the foot."
In the early 1980s, ultrasound began to see some use in equine veterinary diagnostics. Initially a reproductive diagnostic aid, it soon gained attention as a non-invasive method for investigating soft-tissue, intra-abdominal, and intra-articular troubles. With it, veterinarians were able to get an internal view of soft tissue for the first time.
This advancement helped veterinarians distinguish between disorders that might appear similar to the naked eye, pinpoint the source of soft-tissue-based lamenesses, and determine the actual extent of fiber damage.
By the same token, practitioners quickly realized that ultrasound allowed them to monitor recovery. No more guessing about whether or how much a tendon was healing; the ultrasound image showed the mend definitively. Thus, horses weren't being put back into working when an injury only seemed to be healed, but rather when the ultrasound showed it was truly safe.
Just 10 years ago, scintigraphy (nuclear imaging) joined the veterinarians' growing bag of diagnostic aids. At that point, says Kane, "hardly anyone was using it on horses. Now, lots of private practices have it, and every vet school's got one. At racetracks, it's a routine procedure."
Scintigraphy works with a nuclear imaging camera and the injection of a short half-life radioisotope into the bloodstream. Together, these elements create pictures of internal organs, bones, and tissues. From these images, practitioners can judge changes in blood flow and bone growth, and can evaluate soft tissue and organ function. Among other things, this information allows for early lameness detection, giving practitioners (and owners) the chance to fix a problem before it becomes catastrophic.
But that's not all. Other 20th Century diagnostic advancements include the development of instruments to judge temperature better and detect inflammation (such as infrared thermography); refined stethoscopes; improved ophthalmology instruments; endoscopic instruments for laryngeal, tracheal, and gastric diagnostic work; gait analysis monitors; and even equine heart-rate monitors.
Perhaps most interestingly, says Hilsenroth, is that many of these diagnostic tools are not simply adaptations of human instruments. They are being made expressly and exclusively for the equine world. "The other day, I saw a three-meter-10-foot-endoscope," he says. "Obviously, that was designed expressly for a horse. We are definitely seeing a different attitude."
One drawback to this forward motion is price. Says Kane, "Unfortunately, this level of care is very expensive. The owner's ability or willingness to pay doesn't always match the care we can provide."
Medications And Treatments
Regardless of how perfectly you practice prevention and how early you diagnose trouble, horse owners still need medications for their animals. This was no less true at the turn of the 20th Century than it is today. The difference is the types of treatment options available.
One hundred years ago, says Pettit, a horse owner or veterinarian often had nothing more than herbal remedies, plus hot and cold packs, to cure the horse's myriad ills and aches. Treatment techniques and medications were primitive. For example, says Smithcors, "There was a time when purging the horse-giving a laxative such as sulfur and molasses to clean out the system-was a very common practice."
On the bright side, he adds, the rather barbaric practice of bloodletting-used with shocking frequency as a cure for nearly everything in the 19th Century-had largely gone out of style by even the early 1900s. A good thing, too, since a number of horses undoubtedly died from this "cure." (Smithcors notes that bloodletting still is used today, but only for three or four rather rare conditions.)
In 1928, the door to a new world of treatment opened slightly with Sir Alexander Fleming's discovery of penicillin. Then, four years later, the chemical compound prontosil, a precursor of the sulfonamide (sulfa) drugs, was first prepared.
Unfortunately, it would be a few more years before either of these "miracle drugs" was available on a widespread basis, particularly in equine practice. Explains Drudge, "When I started vet school in 1939, the sulfa drugs were not yet available to us. Sulfanilamide was discovered that year, but we didn't know about it. Antibiotics had come along, but were hardly available."
It wasn't really until the 1940s that antibiotics and sulfa drugs became readily available to equine practitioners. At that point, of course, "They made a big change in medical practices of every sort," says Smithcors. Shideler agrees, adding that, "Prior to that, death was rampant."
Indeed, with these powerful allies in their medicine bags, veterinarians suddenly could treat with great success ailments that had seemed incurable just 10 years before. They could save the lives of horses which otherwise would have been doomed.
Still, these hardly were the only medications discovered in the 1900s that have made a lasting impact on equine care. Roughly a quarter-century ago, phenylbutazone hit the scene. It is still regarded by many as the best-known and most effective non-steroidal anti-inflammatory product for musculoskeletal conditions, says Shideler. Within a few years, Banamine also arrived, followed more recently by ketoprofen, further increasing our arsenal of weapons against soft-tissue and intra-abdominal pain.
In addition, says Beeman, the advent of such products as polysulfated glycosamine glycans (Adequan) and sodium hyaluronate (hyaluronic acid) "have been a major boost in our ability to treat lamenesses involving joints."
In the field of equine ophthalmology, he continues, cortisone came into use in the early 1960s. An imperfect medication that often hurt as much as it helped, it since has been joined by "a number of good eye preparations and better diagnostic parameters," says Beeman. He adds that, "Whereas in the '50s, a simple corneal ulcer was a major problem, now we save eyes, and have much less trouble with equine eyes overall."
Such advancements have not come without a price, both literal and figurative. One cost has been the miracle drugs' loss of miracle status. With overuse-and even abuse-of these medications, bacteria have developed resistance, notes Pettit. Now it takes ever-stronger antibacterial drugs to win the battle against ever-stronger bacteria.
In dollar figures, adds Kane, "A single bottle of medicine that a vet might have with him all the time can cost more than an entire truckload that a vet might have had in the old days. Just a bottle of Banamine, for example, can cost $100. Back when it was just penicillin, Bute, and aspirin, it all was relatively inexpensive.
That probably is one more reason that non-drug-based treatments have been gaining attention and credibility in the last decade or so. These include the use of acupuncture, acupressure, electrical muscle stimulation, and electromagnetics as both pain relievers and healing therapies.
Of course, for some ailments, only surgery can offer hope of a cure. Here, as in every other aspect of horse health care, change has come by leaps and bounds this past 100 years.
Arguably the most important initial step came in 1960, when the equine veterinary community finally embraced aseptic, or sterile, procedures. Antiseptic procedure-using iodine to prepare the surgical site, for instance-had been accepted for years. However, veterinarians continued operating bare-handed and bare-faced right up until the 1960s, despite the invention of rubber gloves in 1890 and surgical face masks in 1900. As Pettit says, "Without sterile surgical technique, antibiotics and sulfas wouldn't matter, because you were dealing with so much infection."
Veterinarians themselves weren't entirely to blame for this delayed entrance into surgical sanitation. Horses, being so much larger than humans, were considerably more difficult to lay out on a table and drape with clean cloths. In addition, the absence of good general anesthetics meant that much equine surgery was done with local anesthetics and a standing animal-not the most conducive situation for a truly sterile procedure.
With the introduction of hydraulic tables in 1965, equine surgery edged forward. Prior to that point, says Beeman, simply getting horses on the surgical table took skilled maneuvering and always held an element of risk. Still, it was the introduction of gas inhalation anesthetics around 1975 that truly brought equine surgery into the modern age.
Even before 1900, people were experimenting with surgical anesthesia on humans and animals. H.H. Hickman tried out carbon dioxide as early as 1824, and ether was used successfully in 1846. Nonetheless, choices for equine general anesthetics remained limited to noxious chemicals, such as chlorohydrate, up through the 1960s. Those chemical anesthetics tended to linger in the horse's body long after surgery, often leading to violent, uncoordinated awakenings that undid the good of the surgical effort-and sometimes left the horse more damaged than before surgery. "Horses would literally destroy themselves on waking from surgery," recalls Pettit.
Gas inhalation (using fluorinated hydrocarbons) made a huge, positive impact on equine surgery. "It is far less toxic and so much faster to leave the body, and it allows for better recovery," explains Beeman.
Better recovery rooms with padded walls also aided post-surgical awakenings. Some modern clinics even have recovery pools, where the horse literally awakens in water, supported by a sling.
These major improvements in procedures and tools have made possible operations that never would have been considered in the past. For instance, says Beeman, "Abdominal surgery was practically unheard of when I graduated. Now, we save so many lives with it."
Equine surgical advancements continue to occur. In 1984, for example, Virginia Reef, DVM, Dipl. ACVIM, of the University of Pennsylvania's New Bolton Center, teamed with a human pacemaker manufacturer to install a transveinous pacemaker in a horse, allowing the animal to return to moderate work. Just within the past decade, the introduction of arthroscopic and endoscopic instruments has helped surgeons shave time off both operating and recovery periods. Says Shideler, "With arthroscopy, recovery time can be reduced by two-thirds. Endoscopy for intra-abdominal and intra-articular surgery has de-creased recovery time, stress, and trauma on the tissues."
Even minor surgery has been improved this century with the invention of short- acting sedatives, tranquilizers, and local anesthetics.
Surital, what Beeman calls "the first barbiturate we could really use," arrived in 1965. Within the past 20 years, we've added such products as ketamine, xylazine, and butorphanol.
"We didn't know what tranquilizers and sedatives were when I graduated," recalls Beeman. "Castrating was done with physical restraint-a twitch and pressure, or throw down. Now we use a series of injections."
In general, this array of drugs allows practitioners to customize sedation levels for nearly every situation, whether it's a simple castration or an ovariectomy-a procedure which now can be done as a standing surgery, thus avoiding the risks of general anesthesia without causing the horse undue pain.
One particular benefit of safe, effective general anesthesia, plus the infection- preventing use of aseptic procedures, was to give surgeons more time to operate on their patients. This freedom from haste and worry over infection helped with all kinds of surgery and, in particular, orthopedic repairs.
Suddenly, veterinarians could labor over time-intensive bone reconstructions that they never would have attempted under chemical anesthesia. They could dare to implant skeletal fixation devices, such as pins and screws, that would have been an open invitation to infection using only antiseptic practices.
The results are obvious: "Although people still sometimes have the idea that if a horse breaks its leg you have to shoot it, today, many fractures can be and are being repaired," says Smithcors.
The ability to use such skeletal fixators such as metal pins and screws (common by 1970) rapidly led to research on those items. Many types of materials have been investigated over the years, and studies continue today on everything from porous metals to ceramics to plastic plates with metal cores.
In addition, external skeletal fixators have improved and design options expanded during this century. In the 1920s, splints were the most common fracture-repair device. W.H. Welch in 1921 used elm wood splints soaked in hot water, shaped to the injured limb, and bandaged in place. Other practitioners of the day opted for galvanized iron, yucca board, or aluminum. To stiffen bandages, practitioners chose from such concoctions as wallpaper paste, starch paste, pitch plaster, plaster of Paris, and even glue.
Today, orthopedics has advanced tremendously. Beyond new-age materials, such as plastic polymers, new designs are aiding fracture recovery. For example, in 1990, New Bolton Center announced the use of a device that transferred weight-bearing forces from the bone above the injury down to the ground. It allowed horses to bear weight on the injured limb immediately after surgery.
In 1991, Orthotics International Ltd. introduced its Trauma Brace, said to immobilize an injured limb while allowing for mobility, circulation, and soft-tissue function. In addition, it was designed to allow for better monitoring of infection and swelling than a traditional cast, allowing veterinarians to examine the injury site without having to remove an entire cast.
Another difference between equine health 100 years ago and equine health today is the prevalence of colic and colic-related deaths. We haven't eradicated the problem-and probably never will, says Edward L. Bowen, president of the Grayson-Jockey Club Research Foundation, since that would require perfect horse management. However, he continues, "I think we've come close to finding all the clues to handling it."
Shideler agrees, saying, "We have made a great deal of progress as to why colic happens, what is the body's response, and what are the time lines involved."
Morris Animal Foundation has been among the groups funding colic-related investigations. "Studies, particularly in the late '80s, have focused mainly on treatment, prevention, and risk factors, such as how, when, and what to feed. As a result, there is less colic, and horses have a higher chance of living if they do colic," says Hilsenroth.
Improvements in colic surgery also have helped lower the colic mortality rate. Says Shideler, "Major colic surgery was done in small amounts 50 years ago. But it didn't gain momentum because of very low recovery rates-until the improved anesthesia."
When the surgery was attempted, says Hilsenroth, "Even 30 years ago, the probability of death was a lot higher than today." A case in point: Beeman's first colic surgery. "The mare made it through, but died the next day," he recalls. "If she could have been operated on today, she wouldn't have looked back."
All the same, Shideler notes, "Colic surgery still remains one of the most serious surgical approaches because of the tremendous stress to the horse." The cost to owners remains daunting, as well. "Colic surgery can cost $3,000 to $10,000," says Kane. "The costs are very similar to human medicine. But most horse owners don't have insurance coverage for their horse like they do for themselves or their families."
"The more things change, the more they stay the same." There's at least a touch of truth to that saying when it comes to equine hoof care. Says Heymering, "The first horseshoe-making and horseshoe-nail-making machines were made in the 1800s and remain essentially the same today. I'd say we're still using 19th Century technology."
Part of the problem, he continues, is that horseshoeing entered a sort of dark ages from 1915 to 1960. "There were no horseshoeing schools, few associations, essentially no educational clinics, and the only magazine for horseshoers stopped publication. The dozen horseshoe manufacturers were reduced to two, and the hundreds of types of shoes were reduced to less than a dozen." (All the same, he acknowledges that, in 1929, Victory Racing Plate became the first company to manufacture aluminum horseshoes.)
Since 1960, he says, "It's largely been a matter of regaining lost ground-the rebirth of magazines, associations, schools, clinics, and a variety of shoes and tools for horseshoers."
In fact, many of the modern advancements we've seen in hoof care have come only in the past two decades. These include the following:
• A greater understanding of laminitis due to research by many notable people, including Chris Pollitt, BVSc, PhD; Ric Redden, DVM; and David Hood, DVM, PhD, starting in 1965 and continuing today. Says Beeman, "Research has been remarkable, giving us a better ability to understand the causes. Although we don't know how to prognose the extent of damage, we now have better treatment and management through medication, shoeing, and nutrition."
• The advancement of glue-on shoes (which existed before the 20th Century) to the stage where they now present a viable alternative to nailed-on shoes, thanks largely to the efforts of Mustad and of New Bolton Center farrier Rob Sigafoos, working from roughly 1984 to the present. (Editor's Note: The winners of three of the 1999 Breeders' Cup races for Thoroughbreds were wearing glue-on shoes: Cash Run, Artax, and Cat Thief.)
• Biomechanical re-search by Hilary Clayton, BVMS, PhD, Janet Douglas, MA, Vet MB, MSc, PhD, Hood, Jean-Marie Denoix, DVM, PhD, and others is promising and unique to this century, having initiated in about 1980.
• Research into and understanding of the "natural" hoof, by Jaime Jackson, Gene Ovnicek, Robert Bowker, VMD, and others, starting around 1985 and continuing today.
• Similarly, Dave Duckett's mapping of the internal structures of the foot from external markers (circa 1987) has vastly improved our understanding of normal hoof anatomy.
In addition, farriers and veterinarians have forged a synergistic bond that has helped both professions and, of course, the horses they serve.
No discussion of equine care would be complete without a look at reproduction. This field certainly has undergone as radical a shift as any during the past 100 years. From the days when live cover in a field or pen was the only method available, we have advanced to a point where mare and stallion need not even be in the same country to mate-and where the dam needn't ever carry a foal to produce one.
Among the century's many reproductive achievements, perhaps none has had more impact than artificial insemination (AI), says Paul Loomis, MS, president of Select Breeder Services, a stallion-reproduction facility with branches in Colora, Md., and Aubrey, Texas. Used with horses since the late 1960s and early 1970s (and even longer in cattle), AI now is an accepted breeding method for every major breed and sport association-except The Jockey Club, which still bans the practice in Thoroughbreds.
The advent of AI allows one stallion to breed more mares, more effectively, than ever before. A stallion easily can be booked to 150 or more mares using AI, whereas the average stallion usually can live cover a maximum of 100 to 120 mares in a season (and less for the average stallion). But, says Loomis, there's more to AI than increased bookings: The stallion benefits, and so do conception rates.
"From February through June, a stallion covering 100 to 120 mares would live cover two mares per day," he says. "That is very stressful-and many stallions really don't have the sperm production to gain optimum pregnancy rates that way."
In addition, he says, "Specific genetic traits can more easily and more rapidly influence the progress of the breed this way. And, AI has dramatically decreased disease transmission."
AI has served as a springboard to other reproductive advancements, including transported semen, which, says Loomis, "has changed the demographics of the breeding industry."
Transported semen (also accepted by most major associations) has allowed breeding industries to span the country-and the globe-while minimizing the transportation of mares.
"A Quarter Horse stallion in New Jersey could stand in that state and breed more than 100 mares across the country," say Loomis. "Prior to the AQHA (American Quarter Horse Association) allowing transported semen three years ago, the stallion would have had trouble getting 20 mares to travel to New Jersey, since the breed was fairly concentrated in the West and Southwest."
In order to transport semen, of course, it had to be preserved. By about 1983, cooled semen was commercially available as a viable method of preserving semen for transport or later use. According to Loomis, Massachusetts-based Hamilton Farm first commercialized the process. The farm was standing a French jumping stallion, syndicated for 100 shares, but had no place to hold that many mares on its small property. So they developed the Equitainer-a device for transporting cooled semen.
"They were able to achieve a high percentage of pregnancies for the 1984 season," says Loomis. "It allowed the stallion, at his peak, to breed 120 mares in a season-half in the U.S. and half in France. He influenced jumping stock in two countries at the same time while staying on one small farm."
Frozen semen preservation also helps ensure that a stallion's genes can be passed along even if he can't do it himself. "Horses have fallen ill, been injured, or died-but they are still able to influence the gene pool worldwide through frozen semen," says Loomis.
If not as highly impactful as AI, embryo transfer also has improved the breeding industry. The practice, which came into commercial use in the horse industry only in the early 1980s, allows the embryo in one mare to be transferred to another "recipient" mare for gestation and foaling.
First devised as a treatment for infertile mares, that remains a key use of embryo transfer. However, the method also allows one mare to have multiple foals per year-up to six, according to Loomis. It also means that a valuable show mare can continue her competitive career while simultaneously producing foals. "That's especially important in the sport horse world, where horses don't really reach their performance potential until they are 12 or so," says Loomis. "By then, if they've never foaled, they only have a few years of reproductive health left."
Another mare-centered advancement is gamete intra-fallopian transfer (GIFT). With GIFT, which has just been developed within the past five years, one mare's eggs are placed in a recipient mare, which is then bred directly to the stallion. With this technique, a mare which has, say, blocked oviducts, or one which has been unable to establish pregnancy because of a persistent uterine infection, can still produce.
Other advancements, if not as obviously exciting as these, have helped to improve conception rates and breeding as a whole. These include the use of ultrasound and radioimmunoassay (RIA).
With RIA, which Loomis says came into use in the equine industry in the 1960s, practitioners (and scientists) could measure hormone levels in the horse's blood. "This led to the discovery of many hormones in the mare and stallion that we didn't know were there," says Loomis. Since hormones act on organs, these "discoveries" allowed for tremendous advances in understanding the physiology of reproduction. As Loomis explains, "Until you understand how something works, you can't understand when it's malfunctioning, and you can't develop treatments."
As researchers gained insights, they translated the findings into practical aids. Today, we see the results in such tools as injectable hormones to manage a mare's cycle and the use of progesterone to keep pregnant a mare with a history of aborting.
Ultrasound has given us similarly useful insights into equine reproduction, thanks largely to people like O.J. Ginther, VMD, PhD, of the University of Wisconsin, considered the pioneer of reproductive ultrasound in the horse. For instance, says Loomis, "The use of ultrasound has led to a better understanding of early embryonic development-things we had no clue about earlier or could only learn about through necropsies."
Since reproductive ultrasound allows veterinarians to detect the presence of twins as early as 12 days (when one embryo can be manually reduced), it also alleviates fears over breeding a mare with multiple follicles. In the past, if palpation revealed multiple follicles, a mare owner might skip a cycle rather than risk twins, which couldn't be detected until around 30 days prior to ultrasound (leaving abortion the only option).
Breeders also realized during this century that they could manipulate the stallion and mare's natural breeding season through artificial lighting.
Beyond mere conception, advancements in electronics have allowed for better mare monitoring. Video cameras and on-horse alarms help warn us when a mare is preparing to foal, while blood tests and mare-milk tests help by predicting the due date with fair accuracy.
Once the foals are born, those with problems stand a much better chance of survival. Says Loomis, "With improvements in the level of neonatal intensive care, veterinarians are now able to save foals that would have died just 20 or 30 years ago."
In short, from birth through every step of life, horses of the 21st Century can expect to live far healthier-and far longer-lives than they did just 100 years ago. As Beeman sums up, "It's been a very exciting time." Perhaps the best is yet to come.
It's difficult to look back without also wanting to look ahead, especially when you face the start of a new millennium. So what does the future hold for equine health care? We asked several experts to peer into their crystal balls and tell us what they saw.
Marvin Beeman, DVM, Littleton (Colorado) Animal Hospital-Areas of concern for the 21st Century include the invasion of foreign animal diseases, such as African horse sickness. We will also have to continue addressing the issue of animal rights. But I think we will continue to see better diagnostic tools: Magnetic Resonance Imaging (MRI) is on the horizon for equine practice. We'll see more efficient abdominal surgery. And we'll have better management of joint damage-there is some leading-edge research going on in that field.
Edward L. Bowen, President, Grayson-Jockey Club Research Foundation-I think, in the worst case scenario, if global warming actually alters the climates of land masses, we might reach a point where societies could not condone the wholesale use of land for animals that are not in the food chain. I don't think we can just assume that the human-horse bond will always exist as we know it now.
In a best-case scenario, someone would develop a systemic treatment or medicine that would augment the bloodstream, protecting a horse from any invasion, any disease.
In terms of realistic predictions, I feel very confident that, within 20 to 25 years, we will have developed an equine gene map that will create opportunities to actually breed good health into a horse. The interesting thing will be to see how judiciously that information is used. And I think that different types of imaging will continue to be improved and will be a rapidly developing science. Such a thing (as a lameness meter) could be developed.
Gregory Ferraro, Executive Director, Center for Equine Health, University of California, Davis-I think the main thing we will be addressing, because of continued urbanization and public health concerns, will be vector-borne diseases, cross-species diseases, waste management, and the environmental impact of horses and horse facilities.
The other thing we'll be looking at will be emerging diseases-things we used to consider third-world problems, like African horse sickness. Because of horses and people moving around the world for international competition, these non- traditional diseases, which we didn't used to see in the United States, could be a major problem for us, and we must protect ourselves.
Henry Heymering, CJF, RMF, President, Guild of Professional Farriers-Maybe in this century we'll have computer-controlled truck-mounted laser cutters to make specialized shoes on site! Maybe we'll finally understand laminitis-and all the biomechanical functions of the hoof itself.
Robert Hilsenroth, DVM, Executive Director, Morris Animal Foundation-One area that we seem to be headed into quite deeply is genetics. Not just genetics of the offspring or even diseases with genetic predisposition, but genetically manufacturing vaccines and altering cells; getting down to cell biology and the changing biology of individual cells to prevent, treat, or even eradicate a disease. For example, I believe we will eradicate CID (combined immunodeficiency in Arabians). And there will be studies of the equine genome; we have already funded work on this subject. The human gene map is roughly complete and, because of similarities with the horse, we can use that knowledge to fill in blanks on the equine map.
In general, I believe that we will always have challenges. They say that in seven years, 50% of the information we have today will be obsolete. That's why continuing education is so vital. We have to be poised and ready to attack when challenges do come.
Albert J. Kane, DVM, MPVM, PhD, postdoctoral fellow, Colorado State University-I think there will be an increase in the number of specialized medicines approved and formulated for the horse, including the use of gene therapy. And I think the rapid pace of discovery will continue. We'll see the use of more advanced diagnostic modalities like CT (computerized tomography) and MRI in equine practice.
Paul Loomis, president, Select Breeders Services-Many things are already being done, but have not yet reached the commercial stage, which could impact equine reproduction. Among these is in vitro fertilization, which has not been very successful yet in horses because of technical drawbacks.
Intra-cytoplasmic sperm injection (ICSI)-where you inject an egg with a single sperm to create an embryo-was just done successfully in equine research last year. Similarly, the separation of sperm by X or Y chromosome to pre-determine foal sex has been developed in the past two or three years, but has not yet seen widespread commercial use. And work with bisected embryos-where you divide a six-day-old embryo to create identical twins-is being done in research, but doesn't really have much application outside that realm.
I think we'll continue to see people worrying that these techniques will narrow the gene pool, but I don't think that's something the horse industry needs to worry about. Nobody is breeding for easily identifiable and heritable traits. Genetic heritability of jumping ability, for instance, probably relies more on environmental influences-such as nutrition and training-than on genetics. Breeding is really a roll of the dice. I think these technologies should be used to simplify the reproductive process for the animals and the people, and to make it more cost effective.
Robert Shideler, DVM, Professor Emeritus, Clinical Sciences, Colorado State University College of Veterinary Medicine and Biological Sciences-There is still much to be learned about endocrinology, and physiology-the function of the equine body as a total system. I think there will be a lot of focus on the care and healing of joint problems: cartilage repair, restoring lubrication and nutrition to the joint, reducing pain, and returning the horse to normal function. There are many new techniques being studied in that area. And I think we'll see greater interest in natural products: There is so much available through the body, the environment, and vegetation-it's all right there once we learn to tap it.
The milestones of the 1900s get pretty extensive. It would include antibiotics, aseptic technique, and so much more. Obviously biased, but three from a surgical point of view in my opinion would be the following:
- General anesthesia and its sophistication.
- Development of internal fixation techniques to repair fractures.
- Development of arthroscopic surgery.
—Wayne McIlwraith, BVSc, PhD, DACVIS
"The single biggest contribution to equine health over the last century would have to be the immortal bequest of good ol’ Leroy Coggins: an ageless test of beauty, simplicity, and integrity. Leroy’s lovely is one of those little masterpieces that quietly and unostentatiously enhance humankind—an absolute rarity from the horsy world.
One of the major advances of the 1900s has been the role of internal fixation and arthroscopy in treating musculoskeletal problems in horses.
—Gayle Trotter, DVM, DACVIS
- The communication and dissemination of information (what we do or don’t know) to the profession, the horse industry, and the public.
- Antibiotics; they have made a profound difference.
- The adaptation of human procedures and medications for use in the horse. This would include the staggering technological advances and the spin-offs benefiting horses and providing equine caregivers with tools no one would have imagined just a few decades before.
- The change of the horse from an object of transportation/work to a luxury, pleasure, or sport animal and the associated changes in the level of care people came to expect as these changes occurred.
—Jay Rose, DVM
"All the great advances of endoscopy and athroscopy, surgical techniques, and miracle drugs for arthritic racehorses, etc., etc., would not have anywhere near the benefit for the horse as a sensible breeding plan that avoided in-breeding and mass breeding of essentially unsound horses. Most of the advances aren’t necessarily good for the horse, they are good for the owner; e.g., they get the horse back in action sooner to the owner’s benefit. Despite that, the health accomplishments are as follows:
- Endoscopy and athroscopy.
- Preventive medicine research; e.g., parasite control.
- Increased knowledge of nutrition (unfortunately infrequently employed).
- Change in status of the horse due to increased interest in welfare (slow change, but hopefully occurring).
Top researchers and practitioners of varied backgrounds and from around the world gave us what they considered the top accomplishments or breakthroughs in equine health in the last 100 years.
Parasiticides introduced in the last two decades have drastically changed the picture of internal and external parasites that once posed significant threats to horse health. Since the advent of the avermectin compounds, large strongyles have virtually disappeared as a major cause of vascular disease of the digestive tract. Habronemiasis, or summer sores, has gone the same way. Low level feeding of drugs such as pyrantel tartrate are capable of reducing small strongyle populations to insignificant levels.
Beginning with smaller, safer portable radiographic systems and progressing through to scintigraphy, radiological diagnosis has moved quickly to a very sophisticated level that is of great benefit to the horse industry. Other imaging systems of note include ultrasonography and thermography. The former has opened the door to soft tissue examination related to reproduction, lameness, cardiac function, and visceral examinations. The latter provides useful images of inflammatory processes. Of lesser impact, due to costs and size limitation, are magnetic resonance imaging and computer assisted tomography.
The adaptation of general anesthetic protocols utilizing halothane, and later isoflurane, in horses has allowed major surgery on that species to flourish. Inhalation anesthesia with these agents enables a rapid induction, easily controlled level of anesthesia, and smooth recovery. A major advantage of gas is the profound relaxation that can be achieved. This relaxation plus the smooth recovery that follows have opened the door to new developments in abdominal surgery by allowing accurate evaluation of the problem by abdominal exploration and by facilitating satisfactory closure of the abdominal incision. The concurrent use of ventilators adds control of respiratory function, a critical safety factor in management of toxic patients.
Infectious Disease Control
Disease control through better diagnostic methods and improved preventive medicine via improved vaccines have improved longevity and quality of life for horses. Routine vaccination programs exist for most of the serious infectious diseases, and development of DNA-based vaccines is here and growing rapidly. Diseases like tetanus, the equine encephalitides, and herpes virus abortion have been reduced to insignificant levels with better vaccine production. Diagnostic developments have clearly enhanced the reduction if not the eradication of diseases such as equine infectious anemia. Newer immunological tests are improving understanding of numbers of diseases that have yet to be conquered, such as equine protozoal myeloencephalitis.
Assisted techniques in reproduction have grown from better understanding of equine reproductive function and technological im-provements in areas such as gamete management. Techniques such as embryo transfer, transport of fresh and cooled and frozen semen are commonplace. More exotic practices include retrieval of ova from follicles, fertilization of such ova in recipient oviducts, and many related techniques that have the potential for further development.
—Atwood C. Asbury, DVM
About the Author
Sushil Dulai Wenholz is a free-lance writer based in Lakewood, Colo. Her work appears in a number of leading equine publications, and she has earned awards from the American Horse Publications and the Western Fairs Association.
POLL: Equine Youth Programs