David S. Miller1, MS, DVM; Lauren Harris1, MS; Melissa Syndergaard1,2, BA; Temple Grandin2, MS, PhD; Jack Rhyan3, DVM, MS; M.D. Salman1, DVM, PhD, DACPVM
1Animal Population Health Institute, Colorado State University, Fort Collins, CO, USA; 2Department of Animal Sciences, Colorado State University, Fort Collins, CO, USA; 3United States Department of Agriculture, Veterinary Services, Fort Collins, CO, USA
Zuclopenthixol acetate (ZA) was administered to hand-raised and trained pronghorn (Antilocapra americana) to evaluate the effect of ZA on flight and alarm behavior. Baseline observations were made when the pronghorn were 7–9 mo (30–34 kg) to rank their level of sedation, food and water consumption, locomotion, fearfulness, tendency to approach people, tendency to approach novel items, and tendency to associate with other pronghorn (social reinstatement). Pronghorn were administered ZA 1 mg/kg i.m. using the “Z” technique. The “Z” technique entails applying tension to the skin prior to injection, and subsequently releasing this tension after injection. This results in intact skin covering the i.m. injection site, such that drug cannot leak from the injection site. After administration of ZA, pronghorn were regularly re-evaluated over a 5-day period. In addition, the pronghorn’s responses were evaluated once daily during the 5-day period when they were exposed to novel objects that were intended to incite a mild flight and alarm response. Mild sedation, changes in locomotion, and decreases in food consumption were initially observed, but soon resolved. Treated animals had decreased flight distances and alarm responses. This trial suggests that ZA has some potential for moderating flight and fear responses for some purposes, but there was variability among individuals, and ZA was not a replacement for training or basic management procedures. Further work is needed to evaluate alternate dosages, age-specific variations in dosages, long-acting decanoate formulations of ZA, the efficacy of ZA combined with other neuroleptics, and the potential for moderating undesirable aggression, sexual, and self-mutilation behaviors.