Most research on the canine athlete has been performed on sled dogs, i.e. endurance dogs. In humans, the length of time we can exercise at a low intensity is related to glucose and glycogen depletion time (hence why we carbo-load). This is not the case in dogs. The skeletal muscle makeup of canines is different from ours. These muscles contain unique fibers not typical of many mammalian species. It allow fat to be turned directly into energy. Primarily during activities that are low-to-moderate in intensity but longer in duration.
Fat, and to be more specific, free fatty acids, are used to fuel canines by increasing aerobic work capacity. In extremely high endurance dogs, diets containing 60-70% of Metabolizable Energy (ME) from fat is required to fuel these sustained periods of activity. This level of fat-derived calories increases oxygen consumption, ultimately leading to an increase in available energy by as much as 50%.
The estimated caloric requirement for endurance dogs is dependent on duration but can be two to ten times that which is required for a typical active adult dog. The diet of these animals also requires a substantial amount of protein to maintain muscle mass.
But, what about carbohydrates?
Some studies have found that performance was maintained in endurance canines at low- moderate carbohydrate diets (less than 20% as read on a dog food bag), as glycogen/carbohydrate stores were only used for a short time period before fat reserves become the primary source of fuel.
So, what does one of these diets look like in terms of dog food packaging? An endurance dog would do well on a food with >30% crude protein as dry matter (DM), >20% crude fat DM and restricting carbohydrates to less than 30%, with some studies suggesting carbohydrates can go as low as 10% of ME. A quick and easy way to determine carbohydrate content of a dog food on a DM basis is:
Carbohydrate content (as % DM) = 100 – (% Crude Protein + % Crude Fat + % Crude Fiber + % Moisture + % Ash)
It is suggested that for these types of athletes, 26-35% of ME come from highly digestible animal-based protein. This helps with muscle maintenance, recovery and allows for the required increased cardiovascular stamina.
60-70% ME should come from fat and a low level should come from carbohydrates. Although carbohydrate inclusion can be unnecessary, some research suggests it can be beneficial for freeing fatty acids so that they can be used for energy.
DIETS OF SPRINT DOGS
The energetic requirements of sprint dogs are often overestimated. Due to the short duration of the activity, the increase in energetic requirement is often <25% over the maintenance requirement. Canines that fall into this category are agility dogs, racing greyhounds and some service dogs.
These dogs, due to the short duration of the activity, primarily use carbohydrates for energy while sprinting, as it is readily accessible for a fast sprint. In greyhound racing, it has been found that diets that with 43% ME from carbohydrates outperform dogs on lower carbohydrate diets. In a commercial dog food, this roughly translates to 24-28% crude protein as DM, 12-14% crude fat DM and 45-50% DM carbohydrate, similar to a typical adult maintenance kibble.
WORKING DOGS AND THE ENVIRONMENT
All this good news about high levels of unsaturated fats increasing olfactory performance doesn’t mean common factors that reduce sniff ability disappear. Exercise has an influence on the ability of dog to detect scent. It is theorized that this might be because a dog pants to help decrease its body temperature, and this panting action drastically reduces the ability for dogs to smell, as a dog’s mouth must be closed for precise scent detection.
This gets more complicated when you take a dog out of a laboratory and put it in the field. Where scents are plenty and weather comes into effect. Environmental condition increases the metabolic requirement of a working canine. Where activity outside the “thermoneutral zone” of 20-30 ̊C (68-86 ̊F) increases the energetic requirement. The environment also plays a role in a dog’s ability to scent. Factors such as relative humidity, wind and barometric pressure affect not only a dog’s ability to smell but it also affects how odors move in the landscape.
The more humid an environment, the better a dog can smell, until it rains, and detection ability drastically drops off. Temperature can greatly influence a dog’s ability to detect, as does terrain, poor acclimation to new environment, ventilation and dehydration. These can cause an increase in energy expenditure and leads to panting and a reduction in performance.
- Look for a food with finely ground ingredients. Why? The finer the grind, the better the digestibility of the food.
- When possible, purchase from a primary manufacturer. Quality is more likely to be continually and consistently monitored by people who really know the product.
- Packaging matters. Do your best to maintain food inairtight conditions. If you use a reusable food container, wash it between uses. Oxygen exposure breaks down fats used for detection and energy.
You can also read The working dog diet