The aim of this study was to evaluate the induction of reversible impaction of the large intestine of horses submitted to restricted water intake and treatment with amitraz (formamidine) associated with furosemide. Eighteen crossbred animals of both sexes ranging from 3 to 16 years old were used. They received hay ad libitum, showed an intermediate body condition score, and were considered clinically healthy. The animals were divided into three groups of six animals. Each group was submitted to one of the following protocols: I - amitraz (0.5 mg/kg IV, three injections q12h), furosemide (1 mg/kg IV, two injections q12h), and no water intake for 48 hours. Clinical examinations were performed at 0, 12, 24, 36 and 48 hours after the beginning of the treatment; II - amitraz (0.5 mg/kg IV, four injections q12h), furosemide (1 mg/kg, four injections q12h), and no water intake for 48 hours. Clinical examinations were performed at 0, 12, 24, 36 and 48 hours after the beginning of the treatment; III - amitraz (0.5 mg/kg IV, seven injections q 8h), furosemide (1 mg/kg IV, four injections q 8h), and no water intake for 72 hours. Clinical examinations were preformed at 0, 8, 16, 24, 32, 40, 48 and 72 hours after the beginning of the treatment. Clinical assessment was based on rectal temperature, cardiac and respiratory rates, capillary refill time, intestinal motility, abdominal distention, fecal evaluation, pain, and the degree of impaction. Laboratory tests included hematocrit and concentration of total plasmatic proteins. In conclusion, the protocol III was the most efficient for induction of reversible impaction. This protocol could be a useful tool in controlled studies in the area of equine gastroenterology.
Equine; impaction; large intestine; amitraz; furosemide
