Over recent years, there have been a number of extensive reviews on the traditional methods of diet composition and feeding practices of racing greyhounds. A number of reviews of greyhound nutrition and feeding have been published over the last three decades, summarizing the scientific and practical aspects of dietary needs, ration formulation, and feeding methods.1-8. Some of the data has been extrapolated from the established nutritional needs of working dogs, with adaptations to meet the often higher needs of racing greyhounds. The ‘art’ is knowing how much feed, when to feed, and the likes and dislikes of an individual animal.2. The ‘science’ is understanding the nutritional needs of the greyhound, the relative value of different feeds and the benefits or disadvantages of individual ingredients or combinations.2. A racing greyhound needs an adequate intake of energy for maintenance and exercise, which besides water, is the most important nutrient in a diet and often the one that is limiting to performance.
In addition to maintaining health and vitality, the diet should meet the following criteria:
1.Provide an economical, palatable, low bulk, highly digestible ration to maintain body weight within set limits and ensure optimal performance.
2.Provide optimal proportions of carbohydrate, protein, fat and fibre to maximize energy density while minimisin gut weight and volume compatible with efficient digestive function.
3.Maintain optimal hydration, electrolyte, anaerobic buffering capacity and fluid balance over a variety of climatic conditions and racing distances.
4.Ensure energy and nutrient balance to counteract imbalances and inadequate levels in the diet and meet the specific metabolic demand for performance.
5.Provide a diet formulated to counteract physical stress on the musculoskeletal system, ensure adaptation to and optimal recovery from racing and injury, and maintain the immune response and resistance against disease under high-stress situations of housing and repeated physical exercise.
These aims can be achieved by careful selection of feed ingredients, regular monitoring of body weight, and use of specific supplements to correct low or inadequate feed levels relative to performance requirements and level of stress.
In addition to maintaining health and vitality common to all canine species, greyhounds are a specific athlete with important performance related nutritional needs.
The diet must provide optimal and balanced proportions of carbohydrates, protein, fat and fibre to maximise energy density, while minimising gut weight and feed volume compatible with efficient digestive function and power-toweight ratio. Greyhounds have the highest power-to-weight ratio of any athlete. Gut fill and body weight has a large influence on the speed and ultimate performance of a greyhound running over a range of distances between 300-700 metres. The traditional meat based diets with a total intake of 1000g daily (as fed) containing an average of 50-70% fresh red meat by weight or 500-700g for an average 30 kg (66 lb) greyhound, combined with 30-50% of a low protein, low fat dry food or kibble (300 g daily) are still popular. However, these feed combinations may be excessively bulky for greyhounds to consume, especially as it is often fed as a single meal daily. The actual dry matter content of raw meat in the fresh state is only 20% with water contributing the major portion of the weight and bulk. The advent of low bulk, highly digestible extruded dry foods manufactured on a cereal and oil seed meal base, with high fat (20-30%) and high crude protein (20-30%) as the major energy and protein sources, theoretically distends the gastrointestinal tract to a lesser extent and are digested leaving a minimal bulk of stool.
Low bulk, complete feeds have not been well accepted in greyhound kennels because of a preference for traditional meat-based feeding practices, as well as the perceived higher cost of these dry foods on a per kilogram basis (Table 1). Dry foods processed by steam extrusion are designed to gelatinise starch to facilitate its digestion, enabling a reduced feeding rate of 350-400g daily for a 30kg racing greyhound.
The negative aspect of a high protein, high fat, minimum bulk diet is that many trainers consider that the small bulk of food leaves the greyhound appearing hungry, rather than full and content, when fed once daily compared to a more bulky meat-based diet. The positive benefit of a low bulk, highly digestible diet is the lower stool bulk, which reduces kennel and turn-out clean up time and less faecal odour in kennels when fresh meat is eliminated from the diet.
In countries with a warm climate, the amount of water consumed to maintain hydration can negate any weight benefit obtained from feeding low bulk, high protein and high fat dry foods.
Various studies have found that high protein dry foods may be detrimental to speed and performance. On average, a racing greyhound is able to run 0.1 metre/sec faster (about 2 lengths of the winning margin) over 500 metres when fed a moderate protein diet (20-25% crude protein) as compared to a high protein diet containing in excess of 30% crude protein.
These studies concluded that a dry food based diet, which contained 42% of the energy from carbohydrates, 33% from fat and 24% from protein, provided the best dietary balance to optimise speed and performance over a standard 500 metre race distance. However, greyhounds on this diet were slightly heavier in body weight compared to greyhounds fed a diet containing higher protein and fat, with a lower content of carbohydrate. This difference in body weight was attributed to a greater muscle bulk in greyhounds fed on the medium protein diet.
A proportion of 50% of meat by weight in the total diet has been shown to be of benefit in helping to improve overall speed in a racing greyhound. The ration ideally should contain a blend of meat and dry food to provide energy from an optimum ratio of carbohydrate, fat and protein. This important balance must be provided in bulk that can be consumed easily without adding excess gut weight.
Traditionally, Australian trainers feed a carbohydrate-based meal for breakfast in the form of cooked cereal biscuits.
The traditional evening meal is based on lean meat and dry food, with additional vegetables if required.
A simple calculation (in the table below) based on the energy content of carbohydrates, proteins, and fats can be used to determine the balance needed between these foods to meet the average daily energy requirement for a greyhound in training under moderate conditions (15-25oc). Under cold conditions below 8oc, it is best to increase the carbohydrate content of the diet by 10%. During hot weather above 30oc, an increase in the fat content by 5-7% will help meet the elevated energy expended as a greyhound pants to cool.
A good quality dry food can be combined with a meat base to provide the energy intake in the optimum ratios between carbohydrate (CHO), protein and fat.
The high energy density of fat and the lower cost of freshly trimmed and rendered animal fat by-product of the beef, sheep, pork and chicken meat industries, makes the combination of a fat-boosted minimal meat and commercial dry food diet more economical as well as more palatable to racing greyhounds. Therefore, there is an increasing tendency to feed a minimum meat diet, higher in fat and protein, to reduce feeding costs.
|Use||Energy (Kcal ME)/100g||Crude Protein (%) g/100g||Fat (%) g/100g||Approx. Daily Amounts for a 30 kg Dog|
Group 1 Kibbles dry food
|Meat-based diets||270||13||2-3||200-250g daily mixed with 700g medium 12-15% fat meat.|
|Group 2||Minimum meat diets||290-300||17-20||8-19||250-300g daily mixed with 500-600g medium 12-15% fat meat.|
|Group 3||Complete feeds||330-340||20-24||8-10||550-600g daily or 250-300g mixed with 200-250g medium 12-15% fat meat.|
|Group 4||High-energy complete feeds||400||25-30||20-25||400-450g daily.|
The provisions of nutritional supplements to correct low, imbalanced or adequate levels in meat and cereal-based dry food rations is paramount to meet the elevated needs for minerals and electrolytes imposed on the musculo-skeletal and metabolic system by racing. When trained and fit to race, a sound greyhound can be successfully raced twice weekly. Adequate intake of minerals for bone development on a meat-based diet is particularly important to maintain skeletal strength.
It is estimated that the daily calcium intake needed by a sedentary 30kg dog to maintain optimum skeletal strength is 357mg (NRC, 2006), compared to 6000-8000mg daily for a greyhound in full race training (Kohnke, 1998). It is also recommended to add 20% more vitamin D than NRC (2006) guidelines to dry food formulations; as cereal based dry foods, even with added calcium, have been associated with an increased incidence of bone fractures (Kohnke 1998). The estimated requirement for most other minerals and trace minerals is 2-3 times higher in a racing greyhound as compared to a resting dog.2. Recommendations for B vitamin intake and fortification of feed is at least three times higher than NRC (2006), which reflects the higher metabolic rate during anaerobic exercise of a racing greyhound (Kohnke, 1998; Table 2).
Demineralisation of skeletal and joint structures as a result of high-loading athletic exercise and cortisone-induced muscle catabolism during exercise and respiratory lead to losses of fluid and complementary electrolytes, particularly potassium.
The diet must be fortified with a large range of macro and micro nutrients to meet athletic demand and maintain body reserves, optimum metabolic function and racing soundness.
It is recommended that the ration provided for racing greyhounds contain additional nutrients such as vitamin A, vitamin E, vitamin C and selenium to counteract immune suppression resulting from higher circulating cortisol levels in greyhounds subjected to the stress of training and racing. This will help to maintain optimum resistance against disease and assist recovery from racing and injury.
Please Note: These notes were taken from Kohnke 1998 (Adapted) as the text is no longer in print.
Energy, with the exception of water, is the most important constituent of the greyhound diet.Diets can be manipulated to improve oxidative yields and utilise short and medium chain carbohydrates and fatty acids over a wide range of race distances and climatic conditions.Short-term, high-intensity exercise in the greyhound is fuelled mainly from muscle glycogen and blood sugar to meet the predominantly anaerobic exercise demand.
The energy supply and exercise duration, intensity, and frequency are all interrelated and can be influenced by the individual greyhound’s temperament, kennel and environmental temperature, and efficiency of metabolism.2. The total energy requirement for a racing greyhound is a summation of maintenance, thermoregulation, exercise, and racing expenditure, including behavioural influences and pre-race anticipation expenditure.Regular monitoring of body weight at least once weekly will assist in equating energy intake relative to expenditure.2. All estimates are as metabolisable energy (ME) in kilocalories (Kcal). To convert kcal to kilojoules (kj), multiply by 4.184.
Each 100gm (3 1/3 oz) of:
Carbohydrates, proteins and fat included in the ration blend provide the major sources of energy to meet requirements.
Energy Yield and Food Content. Carbohydrates (sugars and starches) yield 3.5 kcal ME gm,and on average, contribute 40 -45% of the energy in traditional racing diets.2 Meat is low in carbohydrates, contributing only to 5% of the total carbohydrate intake from the traditional 70% meat by weight diets. Dry foods contribute varying amounts of carbohydrates, mainly from cereal grains, ranging from 35 -40% carbohydrates in dry foods containing 27 -30% crude protein and 15% crude fat, to 55% carbohydrates in lower protein (13% crude protein, 2 -3% crude fat), dry foods or kibbles.
Excess Carbohydrates. Excess intake of carbohydrates in the form of cereal grain starches can have a number of adverse effects in racing greyhounds. High starch intake may increase potential glycogen over storage in muscles, with resultant accumulation of higher lactate levels and lower clearance rates, and ultimate earlier onset of metabolic fatigue and risk of exercise rhabdomyolysis or cramping.
High intakes of poorly digested carbohydrates, particularly in the form of cereal-based lower-protein human breakfast or dry dog foods, may also reduce protein and fat digestibility and uptake of sodium, potassium, and calcium because of their higher fibre content. The higher fibre, while helpful in maintaining faecal bulk, increases iliocecal water flow and results in wetter faeces,with less retained as an intestinal reservoir against dehydration during hot weather.
Feeding pre-race snacks provide soluble short-chain sugars, such as sucrose (sugar) and glucose (dextrose) and can lead to increased insulin sensitivity.When excess amounts are ingested in the immediate pre-race period, rebound hyperinsulinemia may be triggered, leading to lowering of blood sugar levels. The combined hypoglycaemia and the effect of insulin decrease on mobilisation of fatty acids and glycerol from lipid stores may also delay liver and muscle glycogen replenishment during the pre-race kennel period.Both these effects, in theory, can cause a risk of earlier metabolic fatigues and reduced race performance. In practice, it is widely recommended to avoid feeding large amounts of soluble sugars in a pre-race “snack” feed, limiting to 15 gm (½ oz) glucose or 60 ml (2 oz) honey .within 4 to 6 hours before racing.
Energy Yield and Food Content. Proteins yield 3.5 kcal ME per gram.Proteins provide a source of energy, as well as essential amino acids, for protein synthesis. As a source of available amino acids, greyhound diets should contain 30 -35% high quality crude protein on a dry matter basis.Protein sources contribute, on average, between 35 - 40% of the total energy needs for a racing greyhound.Lean meat ranges from 17 -21% crude protein on an as-fed basis, or approximately 60% crude protein on a dry-matter basis.Dry foods contain a wide range of crude protein, depending on the content of meat by-products and oilseed protein sources, and commercial products range from 17 35% on a dry-matter basis.2. Most greyhound diets based on meat and/or dry foods to satisfy energy demands contain adequate protein to meet daily requirements.
Excess Protein. High intakes of protein increase the cost of the ration blend, and the elimination of excess poor-quality protein, such as contained in cereal-based dry foods, is an energy-consuming process. It is much more economical, and metabolically more efficient, to feed a diet containing adequate protein, with additional energy provided by fat to greyhounds, during hot weather or those competing in longer-distance races.
Energy Yield and Food Content. Fat or lipids yield 8.5 kcal ME/gram, or approximately 2.25 times that of carbohydrates or protein.Fats are a useful energy-dense feed that provide an energy boost without adding excessive volume or weight to the ration.2. The lipids in fats and oils are a palatable, highly digestible source of energy; greyhound diets should contain at least 12 – 15% fat on an as-fed basis, and greyhounds can tolerate up to 25 – 30% fat on a dry-matter basis.2. Higher fat intake is recommended for excitable, hyperactive greyhounds and during hot or very cold weather conditions.
Both animal and plant oils and fats are highly digestible. Lipids with a high percentage of short-chain (unsaturated) fatty acids remain liquid (oils) at room temperature.2. As the percentage of long-chain fatty acids increases, the lipid becomes solid at room temperature as a fat and digestibility is reduced in fats with high long-chain saturated content.Short to medium chain saturated triglycerides, as contained in coconut, canola, palm, and copha are considered better utilised, as these lipids are digested by pancreatic enzymes without need for bile emulsification.4. Although it is suggested that up to 25% of the total fat be provided by these sources of short to medium chain triglycerides,4. greyhounds may not readily accept these items in their diet. Stepwise introduction over 7 to 10 days may be necessary to obtain acceptance.
Excess Fat. High intakes of long-chain saturated fats, such as beef and mutton fat (trimmings or suet) or butter fat, can reduce overall lipid digestibility, although greyhounds find these animal fats naturally more acceptable. Animal fat sources are generally cheap to purchase as trimmed fat or omental fat from carcasses. However, if more than 60 gm (2 oz) of animal-derived fat is required to boost energy content in the ration during hot weather, or in dehydrated greyhounds, it is preferable to provide additional fat in the form of vegetable oil.
Essential Fatty Acids. Greyhounds require essential fatty acids. The diet should contain at least 1% of linoleic acid, an omega-6 fatty acid, on a dry matter basis, or 2% of ME intake, to prevent the characteristic dry, flaking dermatitis associated with a deficiency in dogs.11. Linoleic acid is the precursor of other linoleic acid family members, linolenic and arachidonic acid, if adequate linoleic acid is available in the diet.
Greyhounds are elite athletic animals which are subjected to extreme physical exertion during racing and the cumulative effects of environmental, metabolic and physical stress when trained and raced on a regular basis. They must be provide with a palatable, low bulk, high energy-dense ration, with a medium crude protein and fat content to maintain competitive speed and stamina within set limits of body weight. An adequate intake of minerals, trace minerals, electrolytes and vitamins to correct low, imbalanced or inadequate levels in meat-based diets, in particular, is essential to maintain musculo-skeletal soundness, optimum metabolic activity, strong immune status and overall health in greyhounds racing between a relatively young age of 15 months to a mature age of between 3 and 4 years.
Table 2: Recommended daily intake (RDI) for a 30 kg resting and racing greyhound on a combined meat and dry food diet. Updated from Kohnke 2002.
|Recommended daily intake (RDI)||Practical guidelines for feeding racing greyhounds.|
|Calcium||3570 mg||600-800 mg|
Supplement meat-based diets to 75% of RDI, dry food diets to 30% RDI: essential in all young greyhounds in training for musculo-skeletal development.
|2670 mg||5000 mg|
|246 mg||800-900 mg|
Add 50% RDI to the diets of nervous or cramping greyhounds or hot weather.
|20 mg||60 mg maximum|
Add 50% RDI, especially to chicken or fish-based diets that are inherently low in iron.
|1.8 mg||5 mg|
Add 50% RDI, especially to chicken or fish-based diets that are inherently low in copper.
|21.6 mg||65 mg maximum|
Add 50% RDI to dry foods if calcium is supplemented.
|3.0 mg||6.0 mg|
Add 50% RDI to meat-based diets.
|100 ug/kg diet||200 ug/kg diet|
Add 100% RDI to high meat diets, 50% to dry food diets (fish has high Se concentrations).
|0.36 mg||1.0 mg|
Add 50% RDI to high carbohydrate diets to optimize metabolism.
|330 mg||3000-5000 mg maximum|
Do not add extra if more than 300g dry food with 1% salt is fed; add 50% RDI to diet in hot weather.
|2670 mg||4500 mg maximum|
Add 50% RDI in hot weather, cramping, nervous greyhounds.
Vitamin A (retinal)
|2250 IU (0.675 mg)||3375 IU (1.0 mg)|
Add 50% RDI to lean-meat diets.
Vitamin D (cholecalciferol)
|240 IU (0.06 ug)||260 IU (0.09 ug)|
Add 50% RDI to lean meat diets, or 360 IU (1.2 ug) when calcium is included in cereal-based dry food.
Vitamin E (tocopherol)
|15 IU (15 mg)||30-100 IU (30-100 mg)|
Freezing meat destroys vitamin E: add 50% RDI to meat diets and up to 100% RDI in fat-boosted diets or high fat dry diets. Do not exceed 400 IU daily as it may affect performance (Marshall 20002 – optimum 100 IU daily, pre-race 150-200 IU).
Thiamin (Vitamin B1)
|600 ug||1.8 mg|
Add at least 50% RDI to meat-based diets.
Riboflavin (Vitamin B2)
|1.5 mg||4.5 mg|
Add 100% RDI to fat-boosted diets.
|6.75 mg||20 mg|
Add 50% RDI daily when racing regularly on high energy diets.
|6.0 mg||18 mg|
Add 50% RDI to diets containing cooked foods (stews)
Pyridoxine (Vitamin B6)
|0.6 mg||2.0 mg|
Add 50% RDI to high protein dry foods.
Cyanocobalamin (Vitamin B
|15 ug||45 ug|
Add 100% RDI to chicken or fish-based diets, which are inherently low in vitamin B
Folic acid (folacin)
|120 ug||360 ug|
Add 50% RDI to all racing diets.
|Internally synthesised||250-300 mg can be supplemented|
Add 100% RDI when racing regularly, but not exceeding 300 mg daily. Limit 250mg daily. Pre-race 500mg. Supplementing with 1,000mg daily appeared to slow racing greyhounds (Marshall et 2002)
(Adapted from Kohnke, 2002)
Please Note: Kohnke 1998: References 1-8 are taken from Kohnke JR. Nutrition for the Racing Greyhound. In Canine Sports Medicine and Surgery. Bloomberg, Dee and Taylor Saunders 1998 Ch. 38 p 328-336.