The Role of Territorial Stress in Conditioned Overeating in Dogs

Overeating is not normal canine behavior: however, it can be conditioned as evidenced by the large number of obese dogs kept as housepets. The purpose of our study was to determine the effect of territorial stress on conditioned overeating in mongrel dogs. Sixteen dogs (8 males and 8 females) were divided into 4 groups: Control (C), Control Reinforced (CR), Stressed (S), Stressed Reinforced (SR). Dogs were housed 2 per run and given dry chow and water ad libitum. SR dogs were offered a can of dog food twice daily while in the presence of nonreinforced dogs. CR dogs were removed to an isolated area and offered a can of dog food twice daily. Weights plus chest and abdominal circumferences were recorded weekly for 13 wks and expressed as average % gain. Weights in air and in water were used to calculate % body fat after 13 wks. Per cent weight gains for the groups were: C=17.6%; CR=20.3% S=7.6%; SR=14.7%. Reinforced dogs gained more than their nonreinforced run mates regardless of the feeding regimen. Moreover both C and CR groups gained more than either S or SR groups, with S gaining the least. Circumferential measurements correlated with weight gains in C and CR groups, but not in S and SR groups. Per cent body fat averages for the groups were: C=35.7%- CR=34.2%; S=24.0%; SR=23.9%. The ratio of % body fat for C + CR/S + SR was 1.46. These findings suggest that territorial stress is an effective factor in reducing net weight gain in dogs even when stressed dogs are reinforced to promote overeating. Supported by NIH Biomed. Res. Grant 4334HO and Departments of Anatomy and Lab Animal Resources.