Abstract
The Proyecto Danta/Baird’s Tapir Project was established in 1994 to study the basic ecology (home range, habitat use, activity patterns, etc.) of the Baird’s tapir (Tapirus bairdii) in Corcovado National Park, Costa Rica. At that time, the veterinary involvement was limited to safely immobilizing tapirs for the purpose of fitting them with radio collars. In 1996, the study was amplified to include more long-term ecologic objectives, such as evaluation of reproductive success, mortality, disease, juvenile dispersal, and genetics. As a result, veterinary medicine has become an integral component of all aspects of the study.
The overall goal of the Proyecto Danta/Baird’s Tapir Project is to provide accurate data on tapir ecology and health for the development of effective conservation and management strategies for the species and its habitat in Central America. Specific veterinary objectives of the study include:
1. Development of safe immobilization protocols for attachment of radio telemetry collars.
2. Documentation of normal health parameters of this population.
3. Identification of disease incidence and exposure of the study population.
4. Elucidation of reproductive patterns in this population.
5. Determination of genetic relationships between individuals.
Tapirs were immobilized using a drug combination of butorphanol/xylazine/ketamine (Torbugesic®, Ft. Dodge, IA, USA; Rompun®, Bayer, Shawnee Mission, KS, USA; and Ketaset®, Ft. Dodge, IA, USA) or butorphanol/xylazine/propofol4 (Rapinovet®, Schering-Plough Animal Health Corp., Union, NJ, USA). Butorphanol and xylazine were administered together in an initial dart at 40–50 mg/animal and 100 mg/animal respectively. First effects were noted at 4 minutes. Sternal recumbency was achieved in 12 minutes. Either ketamine or propofol were used to extend immobilizations beyond 40 minutes. When administered, ketamine was given intravenously in 25–50 mg boluses. When propofol was used instead of ketamine, it was given as a constant rate infusion of 10 mg/m for as long as it was necessary to maintain the animal immobilized. Both ketamine and propofol were discontinued at least 15 minutes prior to antagonism of the induction drugs. The induction drugs were reversed with 50 mg of naltrexone and 1200 mg of tolazoline IM.
During 34 immobilizations of 19 individuals morphometric measurements, body weights (when possible), dental impressions, blood, skin, ectoparasites, fecal samples, and genitourinary swabs have been obtained. Ultrasonographic reproductive evaluation of female tapirs was conducted using a portable ultrasound unit (Aloka 500V, Aloka Inc., Wallingford, CT, USA) when feasible.9 We focused our disease investigation and serologic surveys with consideration of two primary factors: 1) the relatively recent presence of livestock species in Corcovado, particularly Equidae, and 2) the types of diseases previously documented in captive tapirs.7
Dental impressions have been obtained in order to evaluate this technique as a method for age determination. Blood was analyzed to establish a baseline of complete blood cell counts and serum biochemistry panels. The results of the complete blood cell counts and biochemical analysis have been grouped and compared to the current ISIS normals for the Baird’s tapir. Serologic screening for the common diseases affecting horses in Costa Rica was performed. These included equine infectious anemia; equine herpes virus types 1 and 4; vesicular stomatitis; equine influenza; and Eastern, Western, and Venezuelan equine encephalitis. Skin biopsies were utilized for DNA analysis as well as to investigate the presence of the vesicular dermatitis found in captive tapirs. Ectoparasites were collected and identified. Feces was collected and analyzed for the presence of endoparasites, and frozen for later evaluation of reproductive hormones to facilitate correlation with ultrasound data. Genitourinary cultures were obtained to identify common bacterial flora. Ultrasound examination of females was utilized for pregnancy determination in conjunction with a hormonal assay and ecologic data.
The Baird’s tapir is the largest land mammal in the neotropics, and as such represents an effective seed disperser and a potentially important indicator species of the health of tropical rainforests.1-3,8 Once common throughout Central America, the Baird’s tapir is now extinct in El Salvador and endangered throughout the rest of its range.5,6 Despite the current challenges facing tapir conservation, few studies have been conducted to describe tapir natural history or its disease epidemiology. The mission of the Proyecto Danta/Baird’s Tapir Project is to combine the expertise of wildlife managers, biologists, and scientists from various disciplines to help answer the urgent need for basic but paramount information about tapir biology and ecology. Such knowledge is fundamental to effective long-range conservation planning for the Baird’s tapir and its fragile tropical environment.
Acknowledgments
The authors would like to acknowledge that this work was supported with funds provided by the Zoological Society of San Diego, the Wildlife Conservation Society, the Lincoln Park Zoo’s Scott Neotropic Fund, and the World Wildlife Fund for Nature. The authors would also like to acknowledge all those veterinarians and scientists that have contributed to the information presented here: Dr. Roberto Aguilar, Dr. Danilo Leandro Loria, Dr. Don Janssen, Dr. Sandra Allan, Dr. Mary Ashley, Dr. Jim Norton, Dr. Amy Glaser, and the Department of Clinical Pathology at Cornell University.
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