Dr. Robin Radcliffe of the International Rhino Foundation’s Rhino Conservation Medicine Program led a team of scientists from Cornell University, the Palm Beach Zoo and the Medical College of Georgia to Namibia for the first-part of a two-year Morris Animal Foundation-funded Project to study the respiratory and thermoregulatory patterns of black rhinoceros during field capture. This work was made possible through a collaborative effort with the Namibian Ministry of Environment and Tourism’s Rhino Capture Unit under the direction of Pierre Du Preez and Mark Jago with support from rhinoceros expert, Pete Morkel.
Etosha National Park spans the northcentral and northwestern portion of Namibia and encompasses a diverse landscape of mixed acacia thorn scrub, open plains and mopane woodland, all of which surrounds the vast Etosha pan. This oasis in an otherwise arid land abounds with wildlife including lions and leopard, giraffe and zebra, oryz and gazelle, and both black and white rhinoceros. Here in the jewel of Namibia lies one of Africa’s largest populations of the endangered desert black rhinoceros – Diceros bicornis bicornis. It was here that we came to study and learn about the rhinoceros. Capture and anesthesia of rhinoceros across Africa has been practiced for half a century and the principles of field anesthesia have been well established. Yet for all of this pioneering work there remains a dearth of scientifically based information on the most fundamental aspects of the anesthesia process in these prehistoric beasts. Our team was a rare mix of zoological and field veterinarians (Robin Radcliffe and Michelle Miller), University veterinary medical professor (Robin Gleed) and University human medical professor (Art Taft). Our group, funded by the Morris Animal Foundation, the International Rhino Foundation, Cornell University and the Palm Beach Zoo in partnership with the Ministry of Environment and Tourism, was in Namibia to begin a multiyear investigation looking into some of the most challenging aspects of rhinoceros anesthesia: How much air does a rhinoceros breath? What volume of air is moved in and out and what portion of that volume is contributing to gas exchange? How does ventilation and perfusion change with posture? These are a few of the many questions the team set out to answer.
In just over two weeks the Ministry of Environment and Tourism Game Capture Unit immobilized twenty-eight black rhinoceros for routine ear-notching and radiotelemetry work; data collection was conducted opportunistically on twenty-six animals. Blood samples were collected at regular intervals to measure blood gas and chemistry values in free-ranging animals under anesthesia. At the same time, in a subset of animals, the team collected the first in depth data on core ventilation parameters including tidal volume, minute ventilation, and dead space. These measurements will help the scientists make informed decisions about the effects of potent opioid anesthetic drugs and how posture may alter the respiratory and cardiovascular systems; such data may help devise better ways to manage rhinoceros during capture and anesthesia in both the field and zoological setting.
Of course, the scientists met with a number of obstacles along the way. The first was the numerous challenges of conducting work under difficult conditions. The team rented a Land Rover TD5 from a tour vehicle company based in South Africa (Kwenda Safari of BushLore – make a note not to rent a 4×4 from this company!). Upon arriving in Windhoek, the team was disheartened to discover that their expensive Land Rover was not at all what was promised. The vehicle had seen heavy use and was in disrepair. The entire morning of the first day and half of the next were devoted to replacing broken parts – a dead battery that repeatedly failed to start, leaking oil from the engine case, and no air conditioning were a few of the shortcomings noted. With the vehicle finally starting on two salvaged batteries from another, the team could not wait for further repairs so they began the trek 500 kilometers to the north of Windhoek to Etosha National Park. In the coming weeks we would discover a host of other problems with the Land Rover including two spare tires with only three nuts between them (like many of the other key parts on the vehicle the spare wheels had been salvaged from another vehicle and the rims would not accept the nuts on the other wheels), a host of blown fuses that shut down key systems including the head lights, windshield wipers, refrigeration and the like. On one wild chase through the muddy Etosha pan following the capture team at high speeds we could not see through the windshield at all until Art Taft changed a few random fuses on the fly. On another occasion when the fuses did solve the problem and splattered mud covered the windshield, Dr. Morkel stuck his head out of the Land Rover while we crashed through fender high brush on the way to a stumbling rhino. We made it there in record time too!
Despite all of the challenges of keeping pace with a game capture unit in the wilds of the African bush, the investigation went remarkably well. The gas collection apparatus designed and built by Dr. Robin Gleed of Cornell University worked extremely well and proved suitable for field collection of minute ventilation in recumbent rhinoceros in the field. The apparatus, consisting of large four-inch PVC pipes in the shape of giant candy-cane was soon dubbed the “hamster run” because Pierre Du Preez pictured his son fancying such a system of pipes for his pet hamsters. The gas collection apparatus was simple in that it had no moving parts and no electronics, but its function was no less impressive. The simple design of pipes separated by a series of one-way valves allowed the investigators to completely separate the inspired air from expired air. In this way, the team was able to collect the entire volume of air that a rhino breaths out over a minute (minute ventilation). Together with a variety of other data collected simultaneously, this information will help us determine the precise breathing patterns of recumbent anesthetized rhinoceros.
The adventures of a rhinoceros veterinarian and his work around the world will continue in future episodes both in Namibia where the team will return in 2011 and also in Sumatra where the International Rhino Foundation and its partners celebrate a pregnancy in one of the rarest rhinos of the world!
By Dr. Robin W. Radcliffe