Energy expenditure and water turnover in hunting dogs: A pilot study

Hunting dogs display an extraordinary working capacity. They can work for several hours a day for a week or more and cover considerable running distances. The great physical effort displayed by hunting dogs has led to an increased desire among dog breeders for greater knowledge of their specific nutrient requirements, especially for energy and drinking water, which are crucial for endurance. Most experiments regarding sporting dogs have been conducted with Greyhounds and sled dogs, representing the extremes in dog racing, as Greyhounds are sprinters relying on both anaerobic and aerobic fuel, whereas sled dogs are long-distance runners using aerobic energy. Hunting dogs (gun dogs) are likely intermediate in their energy usage, primarily exhibiting endurance activity for several hours interrupted with bouts of sprinting (1). There is also considerable interest among dog owners regarding distance covered and actual speed of their working dogs. The distance covered is likely a major factor influencing the energy spent by the hunting dog. In addition, environmental factors such as air temperature, ground conditions, terrain, and vegetation must have significant influence, although this has to our knowledge never been studied in hunting dogs.
The present pilot study aimed at measuring energy expenditure (EE)5 and body water turnover (BWT) in hunting dogs. Three different running conditions were studied: hunting, road running in harness, which is a common used training activity for hunting dogs, and running on a treadmill, focusing on indications of differences in EE as a result of different ground conditions. The doubly labeled water technique was used to determine EE, and the repeatability of this method was examined by letting the same dogs undertake similar exercise 3 times.