Canine aggression is the most common reason for the referral of dogs to veterinary behaviorist. Aggression has been shown to be negatively correlated with serum serotonin levels in humans, non-human primates and rodents as well as dogs. In addition serotonin is involved in the regulation of hypothalamic-pituitary-adrenal axis activity. But the role of the serotonin and cortisol in canine aggression has not been investigated in Iran. The aim of this study was to evaluate the possible relationship between serum serotonin and cortisol concentration and canine aggression in 40 aggressive and 40 non-aggressive dogs. A questionnaire was distributed to owners of all dogs examined at veterinary hospital of Shahid Chamran University of Ahvaz. The diagnosis of aggression was based upon a history of biting non-familiar persons. Serum serotonin and cortisol levels were measured with an enzyme-like immunosorbent assay method. Statistical analysis was done using the SPSS 16.0 for Windows. Aggressive dogs showed significantly lower serum serotonin concentration (463.7 vs 709.6 ng/ml) and higher cortisol serum concentrations (88.0 vs 39.8 ng/ml), compared with the non-aggressive group (P < 0.05). This study suggests that reduced serotonergic function is associated with aggressive behavior and stress in dogs in Ahvaz.

 A clean bowel preparation prior to X-ray examination is essential to obtain an accurate diagnosis. This study was performed to compare the effect of two different dosages of polyethylene glycol and senna on the bowel preparation of dogs before abdominal radiography. Six adult healthy mongrel dogs from each sex ranging in age from 18 to 30 months received either 4 or 8 g/kg polyethylene glycol or 20 mg/kg senna through an orogastric tube 3 weeks apart. Food was withheld approximately 12 hours prior to drug administration. Radiography was performed 12 hours after bowel preparation. Only water was given ad libitum to animals during the day before radiography. Radiologist unaware of the method of bowel preparation, reviewed the standard radiographs and graded the feces and gas in the colon and rectum, fecal radio-opacity and quality of radiographs on a scale of 0 to 3 (0=inadequate to 3=excellent). Dogs were observed for any drugs side effects up to two weeks after administration of the laxatives. The cleanliness scores of colon for the 4 and 8 g/kg polyethylene glycol and senna groups were similarily 2.17±0.41. Also the cleanliness scores of rectum for the 4 and 8 g/kg polyethylene glycol and senna groups were 2.50±0.55, 1.83±0.75 and 2.50±0.55, respectively. Both polyethylene glycol dosages and senna significantly improves bowel cleansing score in dogs (p<0.05). There were no significant differences between the groups with respect to colon cleansing scores, fecal radio-opacity and quality of radiographs (p≥0.05). 8 mg/kg polyethylene glycol significantly reduce feces impaction in rectum versus 4 mg/kg (p<0.05). There were no clinically differences between the two groups for any of the side effects. It is concluded that 8 mg/kg polyethylene glycol and senna are safe and effective methods of colon cleansing, well tolerated by dogs.

Canine aggression is the most prevalent behavioral problems for referral to small animal hospital in Iran. Since hypothyroidism can also contribute to aggression, this study was performed in order to examine the association between canine aggression and serum concentrations of total thyroxine, free thyroxine, total triiodothyronine and free triiodothyronine. Blood samples were taken from 40 aggressive and 40 non-aggressive dogs referred to veterinary hospital of Shahid Chmran University for routine check-up, annual vaccination or consultation. Serum samples were analyzed by Enzyme-linked Immunosorbent Assay. A 2-way analysis of variance was used to estimate the relationship between serum thyroid analytes levels and aggression, canine behavior, age, sex and breeds. Our results revealed that there is no significant relationship between serum thyroid hormones concentrations and aggression (p ≥ 0.05). Also there is no statistically significant difference based on sex, age, breeds in aggressive and non aggressive groups (p ≥ 0.05). Further studies involving larger groups of dogs, dogs with other behavior problems, comparisons of behaviorally appropriate and aggressive dogs within the same breed would be helpful to elucidate any association between thyroid analytes and aggression in dogs.