TAIL CHASING OR CIRCLING BEHAVIOR IN DOGS

Thirty-two dogs were examined for tail chasing or circling behavior. T he breeds involved included Bull Terriers (14) and crosses (4), Austra lian Cattle Dogs (5) and a cross, German Shepherds (4), three Terrier breeds, and a Standard Poodle. Of the Bull Terriers, 71% (1 0) were wh ite, three were brindle with a white tail tip, and one was tri-color i ncluding white. Three cases involving white Bull Terriers are detailed . One of these, an adult male, was given naloxone which slowed the cir cling behavior within 20 minutes and eliminated it in 85 minutes. By 7 hours post-administration, however, circling had resumed. An 8-month- old male showed some response to a single dose of medroxyprogesterone acetate with abnormal behavior returning over 2 weeks. Postmortem exam ination of the three dogs showed very mild lateral ventricular distens ion in the brains of all three dogs. In addition, one had mild granulo matous meningoencephalomyelitis and another showed mild vascular chang es.