Midazolam Alters Acid-Base Status Less than Azaperone during the Capture and Transport of Southern White Rhinoceroses (Ceratotherium simum simum)

摘要

Capture and transport are important tools for rhinoceros conservation but are associated with morbidity and even mortality. Changes in acid-base status represent major life-threatening risks during rhinoceros capture and transport. In order to reduce these risks it is important to understand the nature of, and mechanisms contributing to, these acid-base changes. Usually, the tranquilizer azaperone is combined with the immobilizing drug etorphine for rhinoceros capture and is also administered as a tranquilizer during transport. In this study we describe changes in acid-base status during rhinoceros capture and transport and determine whether these changes can be reduced by administering the sedative midazolam, instead of azaperone. Twenty-three wild white rhinoceros bulls were captured with either etorphine-azaperone or etorphine-midazolam. During a 280 km road-transport, either azaperone or midazolam was re-administered every 2 h. All rhinoceroses experienced an increased acidity (low pH) in the blood (acidemia) during capture. Rhinoceroses captured with midazolam suffered less from acidemia than rhinoceroses administered azaperone. In all animals, recovery from the acidemia occurred rapidly after capture and pH remained within normal limits throughout transport. We show that using midazolam instead of azaperone, with the etorphine, may help reduce the risks associated with rhinoceros capture and thus, improve animal welfare during transportation operations.