Galloping under race conditions can impose mental, metabolic and physical stresses on a racing greyhound. Greyhounds accelerate to almost 70km per hour within 20 metres of the traps. Their bodies are subjected to high loading forces when cornering, the mental stress of competition, the effort of muscular exertion and post race metabolic exhaustion and fatigue.
The depletion of muscle energy stores and the resulting accumulation of lactic acid and other metabolites in the rapidly contracting muscles, and their retention after the race, triggers the onset of post race fatigue, muscle soreness and delayed recovery processes over the 6-8 hours following a race.
A greyhound that is well conditioned, free of injury and physically fit to gallop over the race distance is likely to be subjected to less physical stress as compared to a greyhound that is not fit enough, or is carrying an injury.
However, even in a well prepared greyhound, a number of post-race problems can develop which can of concern to trainers.
Although we have discussed these individually in previous articles in The Star, it is prudent to group these as post race conditions that have a progressive development over the 12-24 hours after a hard race.
Sub-clinical Cramping
This is a relatively common problem that can cause a greyhound to tail off in the home straight and fail to finish strongly.
A low grade form of muscle cramping, or what is termed ‘sub-clinical cramping should be considered if a structural injury cannot be located or a reason found for a loss of speed in the final stages of a race.
This form of cramping reduces muscle power by limiting the strength and rate of muscle contraction.
It most commonly affects greyhounds that are not fit for the speed or distance of the race.
The present summer months with the increase in electrolyte loss, particularly the physiological loss of potassium salt as greyhounds pant to cool themselves, especially in a greyhound that travels under warm conditions to race, or an excitable animal that ‘runs its race’ before the start.
Both these can lead to dehydration and restricted blood perfusion into the contracting muscles.
An abnormally high level of muscle metabolites and lactic acid can accumulate due to less than optimum oxygen uptake during fast muscular activity.
These can result in low grade muscle soreness, with pain and stiffness developing within 2-12 hours after racing.
In most cases, the majority of greyhounds that a sub-clinical form of cramping, do not exhibit the common tell-tale signs of cramping with a restricted stride or obvious muscle lock-up when racing.
They may, however, appear to deviate or run wide on the last bend as the right hip support muscles, which drive the greyhound around the bends, start to lose contraction power.
When the backline and hind limb driving muscles are examined in the catching area as soon as they pull up, signs of transient muscle firmness, areas of mild ‘knotting’ and pain on examination may be present.
These signs can indicate that a low grade degree of cramping has occurred.
In most cases, by the time the animal has been caught and walked off the track back to the kennels, the muscles free up and the condition missed as the underlying cause of poor performance.
Management to avoid sub-clinical cramping includes an adequate pre-race warm-up by brisk walking, if possible, especially in late night racing.
Provision of 200iu of Vitamin E daily, and popping 2 slow release potassium tablets over the tongue 3-4 hours before race start time, especially in a greyhound that has travelled under hot conditions or is stressed and excited by the noise and prospect of racing.
Ensuring the greyhound is not dehydrated after traveling prior to race kenneling, by providing an electrolyte drink, is essential to reduce metabolic stress that could trigger episode of cramping.
Settling a nervy greyhound by keeping it quiet during traveling also helps to minimize physical stress and the risk of fluid and electrolyte loss that can hamper performance.
Post-Race Urinary Shutdown
We have discussed this particular problem in a review article in The Star.
Up to 30% of male racing greyhounds suffer from an inability to open the bladder to urinate after a stressful race.
During the summer months, dehydration from panting and a lack of adequate hydration can increase the risk of urinary problems, including ‘crystals’ in the urine in bitches and reduced urinary volume and more concentrated urine.
However, post race stress, combined with dehydration, fatigue and ongoing excitement after a race can increase the risk of post-race urinary shutdown.
This syndrome is a particular problem in young male greyhounds that are stressed by a hard or competitive race.
Often the problem is triggered by crowd noise in a young greyhound, the lure noise, other dogs barking and the post race fatigue but continued mental excitement, that over-excites the animal’s nervous system in anticipation of racing which is prolonged after the race.
Affected greyhounds often attempt to urinate after racing, often in the early stages, passing a fine, pulsating stream of urine over a period of 1-2 minutes after a gallop.
In more severe cases, they may be able to pass only a few drops, or develop the inability to pass urine for up to 36 hours after a race.
In these cases, the accumulation of urine in the bladder may lead to severe discomfort and can cause damage to the kidneys due to the increased pressure within the urinary system as the bladder is unable to be emptied.
The condition is not associated with sub-clinical or even mild cramping, or a lower back discomfort or muscle injury where a male greyhound is unable to comfortably stretch out and relieve itself after a race.
Greyhounds that cramp will normally exhibit hind limb soreness and stiffness and while it may be unable to lift its leg comfortably, it will still urinate a dribble, often squatting to urinate.
In severe case, greyhounds develop a painful swelling in the rear of the belly due to a tense, full bladder as they are unable to urinate freely.
Passing a fine tube or catheter into the bladder to drain away the urine may be necessary.
Your vet may decide to leave the catheter in the bladder to ensure continuous drainage for a 12-24 hour period until the muscles relax and the nervous tension subsides and the animal is able to pass urine freely again.
The syndrome is thought to be related to a stress induced suppression of the nerves which control the opening of the bladder exit muscle.
This nerve control is a spinal reflex pathway, rather than originating in the brain, which is normally triggered by receptors in the wall of the enlarging bladder.
However, when physical and mental stresses are imposed by racing, this reflex action is blocked and even though the greyhound prepares to urinate because the bladder is full, the exit muscle remains closed because the nerve pathways are over ridden by the post race tension.
In cases where the urine can be passed in limited amounts as a fine, squirting stream, usually allowing the greyhound to relax in a quiet area after racing will return the nervous impulses to the bladder muscles.
However, in cases where the greyhound cannot relieve itself at all, and the build-up of urine in the bladder becomes painful, administration of specific drugs by your vet to relieve the underlying nervous tension that interferes with the spinal reflex control, is recommended.
In the next article, I will discuss the most serious post race syndrome of rhabdomyolysis or muscle ‘meltdown’ that can develop in a greyhound which over-exerts itself under hot, stressful conditions by running much more than the race distance due to over-excitement and not being able to be caught after the race.
