Page 16 - January 2009 The Game

16 The Game, January 2009
CAN WE PREVENT
SUDDEN DEATH IN
RACEHORSES?
Canada’s Thoroughbred Racing Newspaper
There are few things as devastating as seeing an apparently healthy young horse suddenly stagger, crumple to the track and die. But though it’s mercifully infrequent, we all know it happens.
after a hard workout to see how each animal is handling heat and exercise (digital thermometers, available in drugstores, can give a reading in less than a minute). The normal range for a horse is between 99 and 100.5° F, but after racing or hard training, it is not uncommon to see temperatures in the 102° to 105° F range, depending on the ambient temperature and humidity. If the rectal temperature doesn’t return to normal within 10-20 minutes after exercise, the horse will
In a perfect world, every
jockey would try to win every race. Competition can bring out the best
in man and beast but when gambling is involved, it can also bring out the worst. When I rst arrived at Suffolk Downs in the summer of ‘73, race riding was rough, with very little intervention from the stewards. Even back then when I didn’t know if I’d be knocked right, left or sideways, I hadn’t felt this nervous before a race. I could handle one rider at a time but how would I survive seven jockeys conspiring against me?
the eld. Whoever was setting this race up had done their job. We were completely out of contention. I tried to get The Heckler to relax but he would have none of it. He was in full stride. At the turn, he barely took a breath before switching leads. We caught a straggler half way around and entered the homestretch in sixth position.
Recently, a series of deaths in the sport horse world, with upper-level three-day event horses, have put the spotlight on causes of sudden death in performance horses, especially those who work
at speed (chie y Thoroughbred and Standardbred racehorses, steeplechasers, polo ponies, eventers, and foxhunters). Are these catastrophic deaths just coincidence, or are there some common factors we can address, and perhaps reduce the risk?
need help cooling down, by applying cold water, or a combination of water and ice, over the neck, shoulders and hindquarters. Any time the temperature reaches 107°
I drifted towards the middle of the track, well away from traf c. If anyone wanted to get me, they’d have to bolt across the track to reach me. This was The Heckler’s usual running style
and wouldn’t draw any attention from the stewards. He was eating up the ground even though he should have been tired from his exertions. My only concession to this unusual situation was to forgo the traditional slap with the whip to signal to him that it was time to run. He was full throttle ahead and didn’t need a reminder.
A. Kent Allen, DVM, has served as the Team veterinarian for the United States Equestrian Team on many occasions.
He notes that overall, the incidence of sudden death in performance horses is actually very low. When it does happen, it’s generally one of three causes that is to blame.
F, it is a life-threatening emergency requiring immediate, vigorous cooling. Taking a temperature occasionally during training allows an evaluation as to how well the horse is shedding heat. This provides a measure of tness that is often more useful than pulse and respiration.
I watched the other riders closely
as they warmed up their mounts. No one seemed tense or overly worried as they galloped back and forth, bantering with each other. A couple of them
even smiled at me. Was I letting my overactive imagination run away with me? It looked like business as usual. That is, until we reached the gate.
1. Bleeding, aka exercise-induced pulmonary hemorrhage (EIPH)
Allen also notes that a horse with anhydrosis (the inability to sweat properly) can become overheated with work even in mild climates. Anhydrosis is rare in Canada, but if you have imported a horse from the southern US it is certainly a possibility.
I looked around for Jake, the handler who always took care of The Heckler. There was no sign of him. The man who approached me was someone I didn’t know. Adrenalin rushed through my body as he grabbed the reins and headed into the stall. I knew in that moment how they would get me—in the gate.
I hand rode throughout the stretch, passing the two favourites who were conveniently blocked in on the rail. The jockey in the lead was whipping furiously, his horse shortening stride with every step. He was several lengths ahead of me as I neared the wire, with the second place horse at his anks. I couldn’t quite catch the horse beside me and lost third by a neck.
Pulmonary artery pressures in the horse can go extraordinarily high under extreme exertion -- much, much, much higher than in humans under similar levels of activity. Humans do not get EIPH. But a small trickle of blood from one nostril is such a common occurrence in a racehorse, that we nd it hard to imagine EIPH could be life-threatening.
3. Cardiovascular Irregularities Some major differences in physiology
Increasingly, however, EIPH is being identi ed as a cause of sudden death
in performance horses. Most cases of bleeding are minor, but rarely, horses can suffer more severe episodes, necessitating rest and a full veterinary workup to determine the underlying cause.
and diet between humans and horses mean that horses do not get “heart attacks”, per se. Except in cases of severe parasite damage, they do not develop coronary artery disease, and because they are herbivores they don’t get plaques building up in their arteries.
What could I do? Should I tell
him I knew he was up to something? Discretion seemed the better part of valour on that point. Should I demand that he turn me loose and get the hell out of there? The Heckler, a nervous horse, relied on the handler to keep him steady. I wouldn’t be any further ahead if we were upside down when the gate opened.
I was gasping for air after the race and took my rst deep breath since the whole episode began in the shed row twenty-four hours before. The Heckler’s nervous energy hadn’t completely dissipated and we almost needed the outrider to pull us up. Only on the gallop back to the unsaddling area did he nally relax.
Allen says the worst expression of
this is an internal rupture of a pulmonary vessel, deep in the lungs. Such an occurrence results in sudden death during exercise. This can happen with profuse bleeding from the nose in a vessel near the trachea, but it can also occur in a deep vessel that can ll the lungs or chest cavity, with little or no blood seen in the nose. The horse literally drowns in his own blood, with unconsciousness and death fortunately being swift.
But they can suffer arrhythmias and heart murmurs which can sometimes seriously affect performance. Any
time a heart murmur or arrhythmia is detected by auscultation of the heart with a stethoscope, it should be followed up with echocardiography (ultrasound of the heart) and an electrical exam of the heart rhythm (ECG). The severity of the heart problem and future ability for the horse to continue to race should be determined before the animal returns to work.
The starter called out that the last horse was loading. I set my focus straight ahead, willing every part of my mind and body to be prepared.
The latches opened and we launched forward. In that precise moment, the handler held the rein tight for just an extra half second. The Heckler ran into the bit, the pain of the jolt startling him. The energy of his thrust had to go somewhere.
Bobby was shaking his head as he walked towards us. “That was awfully close.”
That’s why it’s best never to discount nasal bleeding or exercise intolerance. A horse who has suffered an episode should receive a thorough examination with a bre-optic endoscope, to determine the severity of the problem. This exam is often followed by a broncho-alveolar lavage (BAL). A BAL is a way of ushing mucous and cells out of the lower airways for culture and examination. Radiographs of the chest cavity may also be indicated, and a lot can be gleaned just by listening to the airways with a stethoscope.
My feet hit the ground with a jolt. I’d never thought of the exotic bets.
2. Overheating or hyperthermia
Unable to go forward, The Heckler went straight up, rearing high in the air like the Lone Ranger’s heroic Silver. I leaned forward, pressing myself against his neck to avoid pulling him over backwards. From my elevated position, I could see the eld running away from us. So did The Heckler. His front feet touched the ground for barely a second and he rocketed from the gate. My anger and frustration were nothing compared
My legs were like jelly as I walked to the scales and weighed out. When the valet took my tack, it felt like a weight much heavier than the saddle had been lifted. Relief ooded through me and with it, a wave of euphoria. Whoever it was that wanted us out of the race had actually done us a favour. Holding The Heckler back had made him angry enough to run one of his best sprints ever.
Though summers in Canada are brief, they can still be severe, so this cause of sudden death should not be overlooked. Allen recommends that trainers monitor each horse’s temperature during training. Take a rectal temperature immediately
to his. His usual relaxed stride in the backstretch was gone—he was a horse with a mission. It was useless to chase
I started to laugh. It seemed there was justice in the world after all. And out there, somewhere, was a god who kept this naive jockey safe.
Equine Health
By Karen Briggs
Dave Landry Photo
Horses can also suffer sudden aortic ruptures near the cardiac muscle, or in the abdomen. This usually occurs with little or no warning – just a few moments of unsteadiness or reluctance to go forward, followed by collapse. When an aortic rupture happens during intense exercise, the high cardiac output means the horse bleeds out extremely quickly, causing death within minutes or even seconds. When it happens to a horse standing out in the eld, death can take considerably longer because such a horse is not exerting himself, so he has lower blood pressure and minimal cardiac output.
At present, we have no reliable
way of predicting or preventing this
sort of catastrophic event, though veterinary cardiologists are investigating various forms of diagnostic stress echocardiography as one possible way of identifying horses at risk.
“Close? The winner beat me a good three lengths,” I said as I eased out of the saddle.
Hi Ho Silver
A Head at the Wire
A Series of Real Life Stories by Paddy Head
“You just missed the trifecta by a head.”
The Game January 2009.indd 16
12/18/08 7:59:09 AM