1. Faculty of Veterinary Medicine, Department of Veterinary Anaesthesia and Analgesia, University of Sydney, Camperdown, New South Wales, Australia
2. Faculty of Veterinary Medicine, Department of Pharmacology, University of Murcia, 30071 Espinardo, Murcia, Spain
3. Faculty of Veterinary Medicine, Department of Animal Medicine and Surgery, University of Murcia, 30071 Espinardo, Murcia, Spain