The nutritional requirements of exercising dogs

Comparison between the nutritional needs of greyhounds and sled dogs

source: Richard C. Hill
Journal of Nutrition vol 128 no 12, December 1998
starts p2686S, 5 pages long

Most studies of dogs’ nutritional needs have tended to focus on dogs that do little exercise. There is a need for more research, both to prevent injuries (such as hyperthermia and infections from food) and to improve stamina, speed and strength.

Dogs have a unique metabolism, and dogs are better able to use fats than humans are, due to the type of muscle fibres that dogs have. Sled dogs and greyhounds have been the most common subjects of studies of exercising dogs. Results relating to greyhounds can also be useful for dogs doing other sprinting activities, like gun dogs and Frisbee chasers. Results from sled dogs can be useful for other endurance dogs, like search and rescue dogs and hunting dogs.

Greyhound trainers tend to use their own recipes, since there is not much information on their dogs’ nutritional needs. Only about 27% use proprietary dog food, and, of the remainder, all add other ingredients, like raw meat, buttermilk, vitamins and vegetables. Dogs feed too much raw meat can suffer calcium definiciency, though this can be corrected with 1 gram of bone meal per 50 grams of meat. Dogs can also suffer from infections from raw meat. ‘Alabama rot’ is a term used for poisoning by an E-coli H157:07 toxin, symptoms of which can include kidney failure. Cooking the meat destroys some nutrients, like creatine, but removes the risk of infection.

Hyperthermia can be fatal, and can affect exercising dogs when humidity levels and ambient temperature are high, and untrained greyhounds running afternoon races are especially at risk. Allowing dogs to drink water straight after races helps reduce the severity of this problem, as do cold baths. Dogs may also need intravenous fluids. Greyhounds are not usually given water prior to a race, and can become dehydrated. Sled dogs have an increase in water turnover during races.

Sled dogs that are not racing seem to need similar amounts of energy to other young dogs. Dogs need more energy input when it is cold, but this does not apply to sled dogs until the temperature is below about 0 deg C, whereas thin-coated breeds need more energy below about 20 deg C. Distances covered, rather than speed, affect energy requirements. Sled dogs run greater distances, and need almost eight times as much energy for a 490 km race lasting three days at between minus 10 deg C and minus 35 deg C, as they do when resting, whereas racing greyhounds need little more than other breeds.

Sled dogs need more fat, to boost their stamina and improve energy production, above 50% of their energy needs, and they also need high protein levels, accounting to between 30% and 40% of energy levels, to prevent anaemia. Dogs fed vegetable protein are also more likely to suffer from sports anaemia than are dogs fed animal protein. Adding beef to sled dogs’ diets can boost their fat and protein levels. The performance of greyhounds can be improved with moderately high fat levels, but an increase in protein in racing greyhounds’ diets seems to make them run more slowly, in contrast to racing sled dogs. Greyhounds may therefore be better performers with extruded food than with a meat-based recipe.

There is a risk that dogs fed vitamins supplements could receive too high levels. Exercising dogs may need less in terms of minerals and vitamins per joule, since they eat more food. Vitamins C and E may be especially important for exercising dogs, but not enough is known about the correct dosage. Sled dogs can suffer from scurvy if they eat frozen meat over a long period, and this can be prevented by giving them fresh meat.