Reports concerning maintenance energy requirements (MER) in dogs are common but most of the data cover laboratory or utility dogs. This study establishes those of healthy adult pet dogs and the factors which cause these energy requirements to vary. Within the framework of a nutrition teaching exercise, each student followed a pet from his entourage and gathered accurate records of its feeding habits. Data have been restricted to healthy adult dogs with an ideal body weight (BW) which did not vary more than 5 % during the study period. A total of 319 eligible records were analysed using multiple linear regression. Variation factors such as ownership, breed, sex and neutered status, bedding location, temperament and feeding habits were then analysed individually using a non-parametric model. Two models result from this study, one excluding age (r2 0·813) and a more accurate one which takes into consideration the age in years (r2 0·816). The second model was assessed with the main variation factors and shows that: MER (kcal) = k1 × k2 × k3 × k4 × k5 × 128 × BW0·740 × age−0·050/d (r2 0·836), with k1 the effect of the breed, k2 the effect of sex and neutered status, k3 the effect of bedding location, k4 the effect of temperament and k5 the effect of the type of feed. The resulting model is very similar to the recommendations made by the National Research Council (2006) but a greater accuracy was obtained using age raised to a negative power, as demonstrated in human nutrition.

Approximately 40 % of pet dogs are estimated to be overweight and this is associated with health conditions significantly reducing life span and quality. In cats, dietary energy dilution has been reported to increase activity levels and aid healthy body-weight maintenance. Our aim was to investigate this in dogs. For 28 d, a complete and balanced standard dry diet, hydrated to a total moisture content (TMC) of 72 %, was offered to forty-six dogs at individual maintenance energy requirements (MER). Intake, body weight and activity were measured. For the following 28 d, the dry diet was offered at 200 % of MER with or without hydration (7·6 or 72 % TMC) and measurements repeated. When offered diets in excess, body weight increased significantly faster (19·3 g/d) with the hydrated diet (P = 0·001), but activity levels did not change from baseline (P = 0·392), while activity reduced significantly with the dry diet (about 15 %; P < 0·001). Dogs completely compensated for the reduction of dietary energy content, indicating that this is not a useful strategy for maintaining body weight when offered excess food.