The effect of caloric restriction on the behavior of pen-housed dogs: Transition from unrestricted to restricted diet

Abstract

Thirty-nine dogs were assigned to four treatment groups for weight loss. Breed, sex and initial body condition were similar across groups. Treatments included 0, 25, 40 or 50% caloric restriction, based on calculated maintenance energy requirements for the dog's estimated ideal body weight. True maintenance energy requirements and actual caloric restriction were determined retrospectively. Dogs were videotaped simultaneously in the late afternoon, early morning, immediately before the morning feeding, and immediately after the morning feeding during the 3 days prior to initiating calorie restriction, and on days 1–2, 8–9 and 15–16 of calorie restriction. Overall activity levels varied significantly, with the direction of change depending on the size of dog, level of restriction, gender, and time on diet. Small breed male dogs, which were on the most severe restriction based on actual calorie needs as determined at the end of caloric restriction, showed an initial increase in activity prior to feeding, followed by decreasing overall activity as they continued on caloric restriction. Large breed male and female dogs, which were on less intense actual restriction, exhibited a slight increase in overall activity, deriving primarily from decreased sleep and increased sitting, standing and walking. An early (day 1) increase in focused barking by dogs on greater caloric restriction is followed by a significant decrease. In summary, severe caloric restriction may be counter-productive by inducing decreases in activity. Increases in aggressive behavior are not typical, but may occur.