After a couple of good race performances, especially if a greyhound wins as well, followed by a poor race result, can be frustrating in otherwise a healthy, fit greyhound.  Careful observation and a thorough vet check may help to pinpoint the underlying reason for the disappointing run.
Studies have shown that 70% or more poor performances are due to musculo-skeletal injuries, with a high percentage of these being caused by chronic or repeat bone, muscle, joint or tendon injuries.
Some of these are obvious due to lameness, swelling and pain after a poor finish, especially the more serious muscle tears, bruising or more severe strains.
Pad and toe injuries account for 7-10% of limb injuries on grass tracks, and often less than half this incidence of a well-maintained sand surface.

Subclinical Cramping
However, other conditions, such as subclinical cramping, should be considered if a structural injury cannot be located, despite a thorough examination.  Low grade cramping of the back and hind limb muscles will slow speed up the home straight, often with a greyhound losing speed but still attempting to finish within the field.
As discussed in previous articles, this form of cramping reduces muscle power by limiting contraction strength, and rate, especially in a greyhound that is not fit for the speed or distance of a race.
However, low grade dehydration and even depletion of muscle energy stores in an excitable greyhound that “runs its race” when travelling or in the kennels prior to racing, can sap finishing speed.
A quick check for the tell-tale signs of subclinical cramping, shown as a transient firmness and discomfort along the backline or driving muscles in the hind limbs, especially the right upper hind limb area in a greyhound that deviates outwards up the final straight, in the catching area, is the best way to pinpoint this common underlying cause of a poor last quarter section.
In most cases, by the time the greyhound has been caught and walked off the track to the kennels, the muscles free up and the condition can be missed as a cause of a poor performance.
Subclinical cramping is best managed by ensuring an adequate intake of electrolytes, even with a top up of rehydration fluid just prior to kenneling and supplementation with Vitamin E (100-200iu daily) and selenium (0.1mg daily) to increase muscle antioxidant protection.
Recently, many trainers have found that giving 20mL per day of Omega-3/Omega-6 balanced vegetable oil (balanced in a ration of 1 part Omega-3 to 3 parts of Omega-6 fatty acids) will significantly reduce the risk of all forms of cramping, especially if it is given with 100iu Vitamin E per day.
Often daily supplementation of oil and Vitamin E in this way will restore overall race speed and stamina.

Other Underlying Causes
After muscle or other limb injuries are discounted as a contributing factor for a poor performance, then the focus should be directed at the adequacy of muscle energy stores.
In a recent article, I discussed the optimum ratios between carbohydrates (40-42%), fats (30-35%) and proteins (23-25%) in the total energy taken in from the diet.
Often an excessive intake of carbohydrates, usually supplied by cereal based dry foods, or even bread and pasta in some cases, can increase the overall risk of muscle cramping by over-storing muscle glycogen (muscle sugar or energy stores).
This, in fact, is one of the major underlying causes of the condition known as “tying up” or “set fast” in racing horses, especially those on a high soluble starch diet based on oats.
Studies have shown that susceptible horses, often fillies or mares, have an inherited genetic tendency to over-store muscle glycogen.
Their muscles are hard and not as pliable as “normal” horses because they are packed with excess muscle glycogen.
In my experience, it is possible that repeat cramping problems in greyhounds fed too much carbohydrate relative to fat and protein, especially in the evening meal, could develop a similar over-storage problem, as often their muscles, especially the hind limb driving or femoral/hip support group and gluteals, often feel “rock hard” on examination.

Diet Changes
Over the years, I have recommended reducing carbo intake in the evening meal by providing 80% of the meal as meat (which is low – 4% in muscle glycogen) – up to 500 grams and limiting cereal based dry foods (those with 12-16% protein and 10% fat) to less than 100 grams in the evening meal, as well as supplements of salts, Vitamin E and Omega-3/Omega-6 oil.
Bread and pasta, which are high carbo feeds, should be fed only at breakfast and restricted to 11⁄2 slices of bread or 100 grams pasta for carbos, as additions to the normal dry food diet and not in place of it.
A dry food diet with more than 20% protein and 15-20% fat, supplemented with 50% at least of meat, is a suitable balance between carbos, proteins and fats, or a complete high protein/high fat dry food diet.
Greyhounds, unlike sedentary dogs, need some carbos to run, but in cramping greyhounds, direct starch based carbos, often made more soluble and easily digested by the extrusion or cooking process to make the typical hard food, can be an underlying cause of cramping and poor performance.
I always recommend, as I do in racehorses with a glycogen over-storage problem, that the animal be exercised after the carbo based meal, which in a greyhound can simply be a 15-20 minute walk on the lead, to metabolise any excess carbos without draining muscle energy glycogen.

Lack of Carbos
A low intake of carbos, below the 40% total energy content in a greyhound’s daily diet, can on the other hand, also cause less than optimum performance!
Speed and stamina can often be restored by providing an increase in the dry food portion of the meal to boost “carbo” intake for muscle energy storage, especially in predominantly meat based diets in a “normal”, non-cramping greyhound.
Whilst meat contributes creatine and other high energy phosphates for acceleration, it may not provide enough “carbos” to maintain blood sugar and glycogen stores at an adequate level for racing, especially over 400 metre races.
I would be careful not to boost “carbo” intake in a greyhound with “hard” prominent shoulder, backline and hind limb muscles, as these may already contain adequate glycogen for galloping, and may be likely to over store if “carbos” are increased, leading to subclinical and more severe forms of cramping.
Increasing the dry food by 15-20% in weight, reducing meat accordingly, can help restore performance in a greyhound that simply runs out of energy in a race, especially a “hyperactive” type that “burns” up energy prior to racing.
In this case, the medium protein dry foods would be recommended, and on a full dry food diet, it may mean feeding a high protein, high fat dry food as a base, with a “top-up” of lower protein, higher ‘carbo’ dry food in a 4 to 1 ratio by weight.
‘Carbo’ drain should always be considered in a greyhound that runs one good race, followed by lesser performances and a weak finish in ‘back-up’ runs within 5-10 days, but if given 14 days between races, runs well again – obviously if it is otherwise free of injury.