Chapter 110The Racing Quarter Horse
Racing Quarter Horses (QHs) are the sprinters of the racing world, competing at distances of 220 yards (one furlong, 201 meters) to 870 yards (795 meters). The explosive power exerted while leaving the starting gate and the ability to attain speeds of more than 50 mph (80 km/h) to run 440 yards (402 meters) in less than 21 seconds distinguishes the QH from other racing breeds. The American QH originates from colonial Virginia in the 1600s where imported English Thoroughbreds (TBs) were crossed with “native” breeds of Spanish descent to produce a compact, heavily muscled horse that excelled at running short distances. They were known as Quarter Pathers or Quarter Milers, named after the quarter-mile distance at which they excelled. The first race records came from Enrico County, Virginia, in 1674, where match races were run down village streets and in small level fields. Gambling on races was popular at the time, with plantations changing hands over lost bets.1
When settlers moved west with their horses, racing grew along with the popularity of the breed recognized for its versatility for ranch work and innate “cow sense.” The first official QH racetrack was Rillito Park in Tucson, Arizona, opening in 1943. The American Quarter Horse Association (AQHA) was formed in 1940 to register and preserve the breed that presently represents the largest breed association in the world with more than 3 million members. QH racing is now nationwide and spans over five countries on three different continents. In North America alone, $123 million in purse money was paid out in 2007.1 Many racing QH owners, trainers, and jockeys raise horses or participate in Western performance events (roping, cutting, reining, showing, and rodeo events), and they take deep pride in the accomplishments of their horses. Winning the All American Futurity, held each year on Labor Day at Ruidoso Downs, Ruidoso, New Mexico and featuring a $2 million purse ($1 million going to the winner), has been the dream of most everyone in the industry. Los Alamitos Racetrack, a predominantly QH track in southern California, offers at least five races during the year with high dollar purses, with the Los Alamitos Two Million Futurity being the richest. The Champion of Champions race held at the end of the racing year is the most prestigious race for older horses, representing winners of the top races during the year.
Emphasis in the sport is on 2-year-old racing (Futurities), requiring qualifying heats where horses with the 10 fastest times compete in a final 2 weeks later. Horses must be nominated to Futurities with periodic payments to maintain eligibility. The same applies to Derbies held for 3-year-olds, but the purse money is less than for 2-year-olds. Yearling sale prices are driven by precocious, nicely conformed, and well-bred individuals to compete in these lucrative Futurities at 2 years of age and then Derbies the following year.
The AQHA Racing Challenge is a program that was designed to provide more racing opportunities for older American QHs. At this time, 59 races take place in 11 regions across the United States, Canada, Mexico, and South America throughout the year. The horses compete in one of six different types of races, depending on age and ability. The series culminates with a championship night held in different locations.1
The AQHA stud book has remained open to the breeding of TBs ever since the QH breed was formally established. Breeding to TBs is a useful outcross to expand an otherwise small gene pool and maintain the classic quarter-mile distance of 440 yards because some QHs run best at even shorter distances of 300 to 350 yards. Unlike the Jockey Club, artificial insemination is the norm for breeding, and embryo transfer is popular.
Horses are usually broken in the latter part of the yearling year to prepare for racing as 2-year-olds. They are not allowed to race before March of the 2-year-old year, and they are restricted from racing 440 yards until later in the year.2 The early races are very short (220 to 300 yards), and the training schedule is light compared with the racing TB. Most of the 2-year-old QHs are very precocious, big bodied, and naturally fast. They can perform well with a low level of fitness, possibly a risk factor for injury. Once they are fit, they gallop fewer days than does a TB, and fitness in many older racehorses is maintained using a mechanical horse walker at the barn. To race for the first time, the horse must have two satisfactory morning works (qualifying). They generally work from the gate in “sets” of two horses at a time for a specific distance.
QHs race on varying track surfaces around the country, but trainers prefer a firmer surface when possible because a loose or sandy surface poses problems with breaking at speed from the starting gate and getting enough traction for sprinting at high speeds. A new set of injuries is seen when racing on a sandier type of track, especially superficial digital flexor (SDF) tendonitis. Hindlimb lameness, muscle strains, back soreness, and suspensory injuries are also increased. The firmer track is favored, but it may lead to the high incidence of joint and bone injury seen as a result of greater concussive forces. No statistics are available at this time for QH injuries racing on the newer synthetic tracks.
Conformational factors that may contribute to lameness in the forelimb are relative large body mass, poor carpal conformation (back at the knee and bench kneed), upright pasterns, and small feet. Major hindlimb conformational defects (sickle hocks, cow hocks, too straight in the stifles) are undesirable in the QH racehorse because breaking sharply from the starting gate is necessary to be competitive. Any serious hindlimb lameness may limit the horse’s usefulness.
There is no set procedure for lameness examination, but a systematic approach is essential for completeness. An efficient approach is required, however, because many trainers like to examine every horse before it is entered to race. Soundness is imperative for optimum racing performance in the QH breed because races are so short and therefore won or lost by photo finishes on a regular basis. Horses with lameness may be fractious in the starting gate, and those with hindlimb lameness may be slow to break from the gate. Close lameness monitoring is required to maintain QHs in peak condition, and intraarticular therapy is frequently used because of the high level of joint trauma associated with the speed and concussion in these elite athletes.
Watching the horse walk out of the stall and down the shed row is useful and a good time to obtain a history from the trainer or barn foreman. A QH with a sore carpus may be noted immediately by a characteristic wide placement of the limb while walking. History is very useful, such as “the horse was getting hotter than usual at the track this morning,” or “he is digging a hole in the stall and standing in it.” Large barns often keep records of lameness work on each horse, and it is always useful to quickly review past radiographs and joint injections. Observing the horse walk and jog on a hard level surface may accentuate the lameness and aid in diagnosis. Hoof testers should always be used to define foot pain. Joint flexion and palpation are particularly useful owing to the high prevalence of joint problems.
When flexing the carpus, if the limb is raised forward and upward so that the radius is in the horizontal position, the veterinarian may observe an immediate tell-tale withdrawal response of the neck and shoulder muscles as a response to pain. Relaxing the limb, the joints are palpated by placing the thumbs along the individual dorsal borders of the carpal bones while the fingers apply pressure behind the joint to further localize the pain causing lameness. Moving in a distal direction, the dorsal aspect of the metacarpal region, suspensory ligament (SL), digital flexor tendons, and any splints should be palpated for a painful response. The fetlock is flexed, and the suspensory branches are palpated. The distal interphalangeal (DIP) joint is palpated for heat and excessive joint effusion. The digital pulse amplitudes should always be checked because they frequently will be elevated in horses with acute problems of the foot. Excessive synovial effusion, tenderness to palpation, and heat or filling in a specific area of the limb should be noted. The horse’s back, loin, and gluteal muscles are briefly palpated and observed for asymmetry, and then the separate compartments of the stifle are palpated. The medial femorotibial joint is the most common area of soreness in the stifle and may or may not have effusion. A positive Churchill test may be indicative of hock soreness and is quickly performed before palpating the distal aspect of the limb. The history of a poor performance (especially leaving the gate) or recognition of hindlimb lameness at the initial jog usually prompts a more complete examination, with proximal and distal limb flexion tests.
Because of the high incidence of joint injury, digital radiography is the most frequently used modality. The carpus and fetlock are the joints most commonly examined radiologically. Ultrasonographic examination is used for definition of suspensory, tendon, and joint injuries. Ultrasonographic examination is generally unrewarding for detection of proximal suspensory injuries in the QH. SDF tendonitis occurs with varying frequency, depending on the characteristics of the racing surface, and lesions vary widely in severity. Nuclear scintigraphy is used less than in the TB, but it is especially helpful in the diagnosis of tibial stress fractures.