Amitraz toxicity in a horse

Abstract

A 3-year-old Thoroughbred mare was presented to the Equine Clinic, Kasetsart University Veterinary Teaching Hospital following the pour-on amitraz treatment for two days. The horse showed typical clinical signs of colic including depression, inappetite, pawing, sweating, non-defecation, anuria, and ataxia. The clinical examinations revealed heart rate 38 beats/minute, respiratory rate 17 breaths/minute, small and fi rm fecal balls covered with white membrane, and impaction at pelvic fl exure of the large colon. The horse survived after intensive symptomatic treatment with intravenous fl uids therapy, intermittent gastric lavages, intravenous non steroid anti-infl ammatory drugs, yohimbine, and enteral fl uids administration via nasogastric tube. The horse was completely recovered within 72 hours after the initiation of yohimbine administration.