title: Comparison of biochemical stress indicators in juvenile captive estuarine crocodiles (Crocodylus porosus) following physical restraint or chemical restraint by midazolam injection.
abstract: Using a prospective, randomized study design we demonstrate that midazolam sedation minimizes acidosis compared with physical restraint in captive juvenile estuarine crocodiles during handling or noninvasive procedures at preferred body temperature. A dose of midazolam (5.0 mg/kg) was administered intramuscularly into the forelimb of 20 male estuarine crocodiles weighing 2-3.5 kg. Their heart and respiratory rate and degree of sedation were monitored until recovery and then daily for 7 subsequent days. Blood samples were taken at 30, 60, 90, 180, and 360 min. We recorded lactate, partial pressure of carbon dioxide (CO2), hematocrit, glucose, and blood pH. A second group (1.9-2.6 kg) was physically restrained for 5 min and the same parameters recorded. Physically restrained animals demonstrated elevated heart rate, respiratory rate, glucose, lactate, and anion gap compared with the midazolam-treated group. Physically restrained animals had lower pH, bicarbonate, and partial pressure of CO2 compared with the midazolam-treated group. Behavior in the physically restrained group in the days following the study was disrupted, with reluctance to feed and bask, compared with midazolam-treated animals whose behavior was normal. We conclude that midazolam administered in the forelimb of captive estuarine crocodiles of 2-3.5 kg provides predictable onset and duration of sedation enabling physical examination, sample collection, and translocation of the animals with minimal disturbance to lactate, pH, and CO2. Behavior following recovery appears normal.
authors.affiliation: Wildlife Health and Conservation Centre, University of Sydney, Werombi Rd, Camden, 2570, New South Wales, Australia. boongarry@bigpond.com.au
authors.forename: Annabelle
authors.initials: A
authors.lastname: Olsson
authors.forename: David
authors.initials: D
authors.lastname: Phalen
mesh_terms: D000489:Alligators and Crocodiles / Q000097:blood / Q000502:physiology*; D000818:Animals; D000831:Animals, Newborn; D000835:Animals, Wild; D001522:Behavior, Animal; D002245:Carbon Dioxide / Q000032:analysis; D006339:Heart Rate / Q000187:drug effects / Q000502:physiology; D006863:Hydrogen-Ion Concentration; D006993:Hypnotics and Sedatives / Q000008:administration & dosage / Q000494:pharmacology*; D007273:Injections, Intramuscular / Q000662:veterinary; D019344:Lactic Acid / Q000097:blood; D008297:Male; D008874:Midazolam / Q000008:administration & dosage / Q000494:pharmacology*; D012149:Restraint, Physical / Q000009:adverse effects / Q000662:veterinary*; D013312:Stress, Physiological
chemical_list: D006993:Hypnotics and Sedatives; D002245:Carbon Dioxide; D019344:Lactic Acid; D008874:Midazolam
keywords: Crocodylus porosus; estuarine crocodile; hematology; midazolam; sedation; stress