Body mass, maintenance and basal metabolism in dogs

Basal metabolism and body mass are related by the metabolic power function: P = aMb, where P = basal metabolism in Watts, a = mass coefficient, M = body mass in kg, and b = mass exponent. The mass exponent of 117 dogs from the literature b dog = 0.885 +/- 0.024 (r = 0.960; F = 1387; df = 1,115). This mass exponent is significantly greater than the commonly accepted value of 0.75 for mammals. The dog's 95% confidence ellipse is compared with that of mammals with body mass (M) less than 3.2 kg (the lower limit of the mass range in dogs) and greater than 3.2 kg. When M greater than 3.2 kg the interspecific metabolic mass exponent (bi) in mammals is also significantly greater than 0.75 and not different from b dog (bi = 0.869 +/- 0.034; r = 0.919; F = 648; df = 1,120). In mammals M less than 3.2 kg bi is significantly smaller than 0.75 (bi = 0.634 +/- 0.010; r = 0.941; F = 4319; df = 1,561). These data show that in mammals the relationship between the logarithms of basal metabolism and body mass is not accurately described by a single regression line. They also indicate that the commonly accepted 0.75 mass exponent is not applicable to the prediction of basal metabolism in dogs and mammals. The relationship between body mass and maintenance energy metabolism (MEM) in 332 dogs shows that the prediction interval is too wide to reasonably predict MEM in individual dogs. However, the minimum maintenance energy metabolism (MMEM in Watts) can be accurately predicted by a simple algorithm: MMEM = 10.3 + 1.41 x M. The theoretical meaning of the basal metabolic power function is discussed.