What is a canine athlete?
While many dogs in the world exist only as companions, some dogs have purposes beyond purely companionship. Performance canines may be athletes, performing in sled racing, agility, dock diving, and like; or they may have very specific purposes like working livestock, doing search and rescue, or acting as service dogs. Regardless of their extra purpose, when addressing the nutritional needs of our hardworking canines, we should be taking certain things into consideration. This guide will provide you with information that can be used to adjust or create the ideal recipe for your performance dog.
Types of athleticism can be broken down into three categories: Endurance, where the dog works below his maximum exertion level for an extended amount of time; sprinting, where the dog works at high levels of intensity for short periods of time; and “mixed” performance that are neither truly endurance nor truly sprinting activities. Most dogs fall somewhere between these two extremes. You may see these types of exercise expressed as a percentage of maximal oxygen consumption, or VO2max; the higher the VO2max, the more demanding the exercise. “Light” exercise is less than 30% VO2max; “moderate” is 30-60%; and “heavy” is 60-100%. These categories prove useful as we look to address the nutrition of the performance dog. The VO2max for cats has not been precisely established, presumably because the majority of cats believe that hell will freeze over before they can be convinced to run on a treadmill.
Endurance performance utilizes more aerobic metabolism, and focuses on a conversion mechanism of food into energy called aerobiosis. Aerobiosis involves converting fats into energy, meaning that fats as free fatty acids become the most important energy source. 70-90% of sustained endurance work is derived from this fat metabolism; relying on carbohydrates will result in the build-up of lactic acid, which results in reduced performance, fatigue, and stiffness.
The dog’s body can be “trained” to utilize free fatty acids as the primary source of fuel. The best way to achieve this is to continue feeding higher-fat diets both before and during the training season; if weight gain becomes a concern, reduce the overall calories rather than reducing specifically the amount of calories from fat. This transition should take place over 8-12 weeks.
Examples of endurance exercise: Sled races, bikejoring, carting, all-day hunting, farm dogs
Sprint performance utilizes more anaerobic metabolism and focuses on a conversion mechanism of food into energy called lactic anaerobiosis. Lactic anaerobiosis refers to two methods of carbohydrate to energy conversion, meaning that carbohydrates are the important energy source. The first method is called anaerobic glycogenolysis, which utilizes the body’s stored glycogen at the very start of the exercise for a very short and strong burst of energy; because dogs’ have limited storage capabilities for glycogen, it lasts for roughly 30 seconds. The onset of fatigue for the high-intensity performance dog is directly correlated to the depletion of glucose and glycogen.
The second method is glucose oxidation, which utilizes the glucose in the bloodstream and tissue and turns it into energy. This energy source lasts for no more than a couple of minutes, which is why it is the ideal method for sprint performance, and not endurance.
Examples of sprint exercise: Agility, disc dog, dock diving, lure coursing, greyhound racing, flyball
An increase in energy needs is directly correlated to the distance traveled, rather than only the intensity of the activity; while sprint-type work does increase the expenditure of energy, higher intensity is limiting on the duration of the exercise which reduces the total caloric expenditure. The following table is based on the average active dog maintenance energy requirement of 132 x (kg)^0.75:
When compared to the average “couch potato”, the increase would appear to be significantly more.
The average energy needs for the sedentary, indoor adult dog can be determined using the equation 100 x (ideal body weight in kg)^0.75 = total daily kilocalories. For endurance dogs, we expect to see a requirement 1.5-2.5x that number, depending on a variety of factors: ambient temperature, type of activity, distance traveled during activity, level of conditioning, overall fitness, breed, coat type, leg length, age, and terrain. Did “leg length” make you raise an eyebrow? It’s true! A trotting dog with longer limbs can expect to need an additional 0.6 calories per kilogram of body weight per kilometer, while a trotting dog with short limbs would need 1.3 calories per kilogram of body weight over that same distance.
Cold weather can further increase the overall energy requirement by an additional 50%, especially for short-coated breeds; a dog with a thicker coat would not need to use as much energy to stay warm, so he would need less. Hot weather, too, can influence energy requirements, but usually requires an increase of only about 15%.
When we approach nutrition for the canine athlete, we focus on a few things:
-Provide high-quality, highly digestible protein from animal sources
-Provide adequate energy levels from appropriate sources for increased energy expenditure
-Reduce inflammation through fatty acids
-Reduce oxidation through increased antioxidant activity
Dehydration can be a significant concern for working dogs and care should be taken to ensure that this does not occur. Dehydration causes the heart to have to work harder to pump thickened blood and there is less plasma fluid to provide oxygen and nutrients to bodily tissue. Low hydration will also cause a dog to have lowered energy, focus, and response time, thus negatively impacting performance. Conditions that determine water requirements include:
- Ambient temperature
- Duration of work/exercise
- Ability to pant
- Weight of dog
- Protein content of food
While most dogs regulate their own water intake (and have incredible body processes to maintain their fluid/plasma balance as well), some will become too stressed during events to “remember” to drink. For those dogs, bone broth may be more tempting.
Following competition, the dog may want to consume a large amount of water very quickly- but this can cause stomach distention. Instead, allow your dog first to cool down, and then offer frequent chances to drink small amounts of cool water.
We know that our three macronutrients- protein, fat, and carbohydrates- provide energy for our dogs. Protein should be the last of these to be converted into energy- we do not want our athletes to be relying on energy from protein. Why? The answer is simple, really: protein should be used by the body to maintain and repair tissues; create hormones, enzymes, cells, and antibodies; and maintain the dog’s fluid balance before it ever has to be used as an energy source. The first of those- maintaining and repairing tissue- is especially applicable to the performance dog, who already is at higher risk for muscle strain or damage. Instead, we look at fats and carbohydrates, and where our focus should be depends entirely on the dog in front of us and the type of athleticism that applies to him.
That is not to say, however, that lower protein should be fed- the opposite, actually! As the dog builds muscle, his overall protein needs increase and and this protein status will influence his susceptibility to injury. Training and exercise builds muscle, which increases the synthesis of blood proteins, which increases blood volume, which finally increases the blood circulating throughout the body- all of which requires more protein!
Additional factors that increase the working dog’s need for protein include lowered environmental temperatures and thick coats, as fur is mostly protein.
Specific types of amino acids called branch-chain amino acids (BCAA) have been studied for their beneficial effects within the body, particularly on skeletal muscle, the immune system, and cognitive function. Supplementation of BCAA-enriched mixtures in mice has shown to improve endurance, coordination, and muscle fiber size. BCAA supplementation in active dogs has improved cognitive performance, with the study highlighting agility, working, obedience, and show dogs as likely to benefit. While separate supplementation is likely not needed, feeding meats high in BCAA could be beneficial.
As discussed above, fats are crucial in any dog’s diet but especially that of the working dog. Fats, or lipids, are higher in energy per gram than both protein and carbohydrates. They are made of fatty acids that may be essential or non-essential, and they can be saturated, monounsaturated, or polyunsaturated. Generally in fresh food diets the dog ends up with a high percentage of his daily fat coming from saturated fats, which are found in high numbers in animal tissue; these are non-essential fatty acids. Dietary fat is utilized as the main energy source for sustained performance, and has been shown to increase a dog’s oxygen consumption, thus increasing his capability for aerobic performance. Dietary fat also has a sparing effect on muscle glycogen stores, allowing for prolonged use of muscle glycogen.
We also want to focus on polyunsaturated fatty acids, several of which are essential.
While higher-fat diets are very common for working dogs, the type of fat matters. Saturated fats, especially medium-chain triglycerides (MCTs), like what can be found in coconut or palm oil, is not recommended. High MCTs has been linked to reduced olfactory capabilities, which would negatively impact many types of performance.
Polyunsaturated fatty acids in the form of essential fatty acids should be included in the diet of every dog, but the working has an increased need for them. As the dog’s body has a higher demand to work, muscle inflammation can come around as a result. This is where the application of increased omega-3 fatty acids comes into play.
The parental fatty acids are linoleic acid (LA, omega-6) and alpha-linoleic acid (ALA, omega-3), which the dog can then convert into other, more physiologically necessary fatty acids. Linoleic acid is converted into arachidonic acid (AA) and alpha-linoleic acid is covnerted into eicosapentaenoic acid (EPA) which is then converted into docosahexaenoic acid (DHA). However, this conversion rate is quite low, and thus dietary sources of EPA and DHA should be provided.
One of the most important things to remember about fatty acids is that they are competitive– they compete for the same enzyme and metabolic pathways while also resulting in different reactions within the body. AA, EPA, and DHA are all precursors to eicosinoids– molecules that are released from cellular membranes in response to trauma and that have immune and inflammatory responses. The type of eiconsinoid synthesized depends on the availability of the type of fatty acid. Eicosinoids produced by AA are considered to be more inflammatory in nature, while those produced by EPA and DHA are far less inflammatory, and are actually considered to be “anti-inflammatory”.
By increasing the omega-3 fatty acids in the diet will lead to a decrease in pro-inflammatory eiconsinoids and an increase in anti-inflammatory activity. When formulating for performance dogs, I prefer my omega fatty acid ratio- omega-6:omega-3- to be between 2:1-5:1 and no more than 10:1.
The best sources for EPA and DHA are found in marine sources, whether from raw or cooked oily fish, or a high-quality fish oil supplement.
Carbohydrates are generally not needed in large amounts in the diets of most performance dogs, but do provide the ideal source of glucose and glycogen needed for bursts of energy. Carbohydrates will be broken down during digestion into the simple sugars galactose, fructose, and glucose; galactose and fructose are converted into glucose in the liver. Glucose is distributed to body tissues through the blood circulation, where it will be used as an energy source, converted into glycogen, or synthesized and stored as fat.
Glycogen stores are key during exercise and are utilized in both aerobic and anaerobic work, and glycogen metabolism enables fat metabolism to continue during sustained work. As mentioned earlier in the guide, the dog’s body has a predetermined capacity to store glycogen, and the amount of glycogen available for use in the working muscles is thought to be directly correlated to the onset of fatigue.
In the athlete’s diet, complex carbohydrates in the form of oats, barley, buckwheat, rice, and even pasta are all common. However, it is important to be cognizant of how much carbohydrate is going into diet; studies have shown that high-carb diets negatively impact endurance racers (sled dogs), causing stiffness and a greater propensity for injury.
Dietary fiber exists in two forms: soluble, and insoluble. Soluble fibers are fermentable in the large intestine, leading to the production of short-chain fatty acids which in turn are used as energy for the cells that line the intestines, improving overall gut health. Insoluble fiber is non-fermentable and is instead digested in the small intestine, slowing gastrointetsinal transit time and reducing stress-induced diarrhea. Most sources of carbohydrates provide both insoluble and soluble fiber, just in varying amounts.
To quickly resolve stress diarrhea, it is recommended to add 1 teaspoon of dry psyllium husk to the diet of a 20 to 30-kg dog. Psyllium husk is insoluble fiber that absorbs excess water in the intestines (the reason for diarrhea). More can be added if necessary.
Large amounts of highly fermentable fibers can cause loose stools that can exacerbate water loss.
Generally, the best way to support the working dog is to provide adequate nutrition that meets his daily recommended allowances per ME as established by the NRC; this becomes more important in higher-fat diets, where overall nutrient density will be diluted.
Calcium in the amounts of 1.5-4 grams per 1000 kcals should be provided with adequate phosphorus as well (generally not an issue in raw or cooked, meat-heavy diets); the overall ratio is thought to be unimportant if adequate amounts of both calcium and phosphorus are provided.
Recent studies have shown that excess fat in the diet may indicate an increase in calcium, iron, zinc, copper, and manganese; these are divalent cation nutrients that chelate, or bind to, free fatty acids, thus reducing their bioavailability. While most NRC-balanced diets provide these above the recommended allowance, consideration should be given if formulating a higher-fat diet.
Vitamins are either fat-soluble (A, K, D, E) or water-soluble (Bs, C). Water-soluble vitamins should be given extra attention as they are excreted in the urine, which can become more of an issue in performance dogs (increase in food and water = an increase in urine output). For this reason, small amounts of supplementary B vitamins may be indicated depending on the amount already being provided through the diet. Whether or not the supplementation of additional vitamin C, an antioxidant that a healthy dog can synthesize on his own, is indicated appears to depend on the type of activity; while it slows racing greyhounds, it has proven beneficial in Foxhounds performing field trials, as well as endurance-racing sled dogs.
The majority of fresh food diets that contain both muscle meats and organ meats will have adequate vitamin A, but vitamin D is a nutrient commonly low in diets not evaluated against a nutritional standard such as the NRC (please see my PMR guide here). Vitamin D is most easily found in oily fish like salmon or mackerel, and is found in lower concentrations in eggs, especially those that are pasture-raised.
Vitamin K is synthesized endogenously by healthy dogs and supplementation is generally not needed.
Vitamin E, another antioxidant, is of particular importance to the performance dog. Performance dogs experience greater levels of oxidative stress. This exercise-induced oxidative stress causes fatigue, muscle damage, and ultimately impairment of the immune system. In addition to exercise-induced oxidative stress, fatty acids (which most performance dogs are supplemented with) are fragile and easily oxidize. This oxidation process is a domino effect, and without antioxidants to stop the process, it does not stop once it begins.
To continue from the last section, there are antioxidants that can be provided beyond those that are considered dietary requirements (E, C, selenium, and manganese).
Many of these are phytonutrients, or nutrients that are found in fruits and vegetables; the majority of them are what give different fruits and vegetables their specific pigmentation, such as anthocyanins in berries and beta-carotene in carrots. These phytonutrients have been shown to not only reduce oxidative stress, but also increase intracellular communication, reduce the risk of certain types of cancer, reduce the risk of heart disease, and increase cognitive function. In addition to those found in fruits and vegetables, lutein in egg yolks and astaxanthin in salmonid fish and crustacean shells are also beneficial.
Taurine is a cardioprotective (heart healthy) amino acid that is typically synthesized from the precursor amino acids cysteine and methionine. Because it is water-soluble, supplementation of moderate amounts is generally regarded as quite safe and beneficial. In addition to its cardioprotective aspects, taurine also acts as an antioxidant specifically against mitochondrial oxidative stress.
Co-enzyme Q10, or CoQ10, exists within the body of every animal and is of special importance to the organs that have high demands of oxygen- the heart and the brain, two organs that work overtime during performance. Because of its affiliation with oxygen, it will bind to oxidizing agents, serving as a key antioxidant. Supplementing with CoQ10, which is fat-soluble, is very safe.
Dogs involved in activity that is physically demanding are more likely to suffer from joint issues as they age, and acute trauma even during younger years. For these reasons, placing the working dog on a preemptive joint health supplement can be very beneficial. The most commonly used are glucosamine + chondroitin sulfate products, such as Dasuquin, and green-lipped mussel powder, which is more concentrated in the powder form than as the whole shellfish.
Dogs recovering from injury may benefit from proteolytic enzyme therapy.
Fresh foods made from high-quality protein, animal-based fats, and moderate carbohydrates should still be provided during the off season, but caloric requirements will decrease down to normal active dog maintenance levels. For endurance athletes, maintaining higher-fat diets will help the body to “remember” to continue using free fatty acids as fuel during the performance season.
Omega-3 fatty acid supplementation can be decreased when the athlete is in his off season as well.
CONSIDERATIONS FOR DIET FORMULATION
Richard C. Hill, The Nutritional Requirements of Exercising Dogs,
The Journal of Nutrition, Volume 128, Issue 12, December 1998,
Pages 2686S–2690S, https://doi.org/10.1093/jn/128.12.2686S
Canine and Feline Nutrition, 3rd Edition. Case et al.
Nutrient Requirements of Dogs and Cats. NRC.
Performance Dog Nutrition: Optimize Performance with Nutrition.
Dr. Joceylnn Jacobs.
Canine Performance Nutrition. Justin Schmalberg, DVM.