MEDICAL MANAGEMENT of CAPTIVE TAPIRS (Tapirus Spp.)
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MEDICAL MANAGEMENT OF CAPTIVE TAPIRS (Tapirus spp.) Donald L. Janssen, DVM, Dipl. ACZM,* Bruce A. Rideout, DVM, PhD, Dipl. ACVP, and Mark E. Edwards, PhD Zoological Society of San Diego, San Diego, CA 92112, USA Abstract Medical and pathology records were reviewed from North American institutions and summarized for analysis. Several anesthetic regimens have been used successfully in tapirs. Tapirs have traditionally been anesthetized with etorphine, but combinations of "2-adrenergic agonists and butorphenol appear to provide some cardiovascular advantages. Common clinical signs of tapirs found in this survey include mandibular swellings, corneal opacities, diarrhea, skin vesicles and epidermal sloughing, chronic weight loss, lameness, colic, nasal discharge, and dyspnea and coughing. Hematologic and serum chemical values were similar to those of other Perissodactyla. The highest mortalities were in the neonatal and adult age groups. The main disease problems identified were noninfectious gastrointestinal disease and infectious respiratory disease. Pneumonia from mycobacterial infections occurred twice in this survey, and stresses the importance of performing tuberculosis monitoring in tapirs. Tapirs should be fed using strategies similar to that of other Perissodactyla, and successful diets usually include forages and nutritionally complete pelleted feeds with minimal produce. Attention to the husbandry concerns following parturition is important for neonatal survival. It is recommended that tapirs be evaluated medically prior to being relocated. Resumen Los registros médicos y patológicos de instituciones en Norte América fueron revisados y resumidos para su análisis. Varios procedimientos anestésicos han sido exitosamente usados en tapires. Tradicionalmente los tapires han sido anestesiados con etorfina, pero se ha demostrado que las combinaciones de antagonistas "2-adrenérgicos y butorfenol tienen ventajas cardiovasculares. Signos clínicos comúnmente encontrados al examinar tapires incluyen inflamación mandibular, opacidad corneal, diarrea, vesículas dérmicas, descamación epitelial, pérdida crónica de peso, laminitis, cólicos, descarga nasal, disnea y tos. Los valores hematológicos y químicas serológicas son similares a aquellos encontrados en otros perisodáctilos. Las mortalidades más altas se encuentran en neonatos y en individuos de edad avanzada. Los mayores problemas médicos encontrados son enfermedades gastrointestinales no infecciosas y enfermedades respiratorias infecciosas. Una neumonía por infección micobacteriana ocurrió dos veces durante este estudio y evidencia la importancia del control de tuberculosis en tapires. Se debe alimentar a los tapires siguiendo estrategias similares a las utilizadas con otros perisodáctilos, y las dietas adecuadas usualmente incluyen forrajes y concentrados nutricionalmente completos. Los cuidados posteriores al parto son sumamente importantes para la sobrevivencia del neonato. Es recomendable que los tapires sean evaluados médicamente antes de ser transferidos. 1996 PROCEEDINGS AMERICAN ASSOCIATION OF ZOO VETERINARIANS 1 Introduction Of the land megavertebrates, tapirs have received relatively little attention or study in the wild or captivity. Tapiridae is a small family of four species within the single genus Tapirus. There are three New World species (T. terrestris, the South American, lowland, or Brazilian tapir; T. bairdi, the Central American; or Baird’s tapir; and T. pinchaque, the mountain or wooly tapir) and one Old World Species (T. indicus, the Malayan, saddleback, or Asian tapir). Fossil evidence shows that tapirs have survived nearly unchanged for over nearly twenty million years. The majority of tapirs in captivity are Malayan and South American tapirs. Baird’s tapirs are less common, and mountain tapirs are extremely rare. In the wild, all tapir populations are threatened by habitat loss and hunting. The South American tapir is listed on Appendix II of CITES, and the other three species are listed on Appendix I. The mountain tapir is nearing extinction in the wild. The body mass of adult tapirs range from 200-400 kg with the female often being larger than the male. The Malayan tapir is the largest species, and the mountain tapir is the smallest. Individuals have lived over 30 yr in captivity. They reach sexual maturity between 2 and 4 yr. Tapirs give birth to usually single, and rarely twin, precocial calves after approximately a 13 mo gestation. Several authors have published reviews that describe the biology and husbandry of the Tapiridae.3,19,20,23 A bibliography was recently produced which includes citations on the medicine and biology of Tapiridae.15 The American Zoo and Aquarium Association (AZA) sponsors a Taxon Advisory Group and Species Survival Plans for the Tapiridae. Anatomic Notes The internal anatomy of the tapir is analogous to the domestic horse and other Perissodactyla. The guttural pouches of the tapir are similar to those of the horse. They are located in the pharyngeal region, lateral to the hyoid bones.19 The testes are in the inguinal canals, which are located in the subcutaneous tissues on either side of the penis.13 Tapirs lack a gallbladder. The tapir is a hindgut fermenter with a relatively small stomach and large cecum and colon. The squamous portion of the stomach is small and is located in the cardia (near the gastroesophageal junction). The kidneys, like those of the horse, are not lobulated. The normal parietal and visceral pleura can be thick and prominent, but only the Malayan tapirs should have adhesions between the lung and chest wall (as in the elephant).18 Methods Medical and pathology records were reviewed from 18 North American institutions. Anesthesia and clinical pathology records were compiled into MedARKS format for analysis. Clinical signs were categorized following review of individual medical records. Pathology findings from 108 cases from 1960-1995 were summarized into a database. Diagnoses were standardized and simplified to avoid confusion arising from different pathologists using different terms to describe the same disease process. Diagnoses were then divided into two categories based on evaluation of the clinical history, gross, and microscopic findings. Primary findings are those that are interpreted as the major factor contributing to the death of the animal. Secondary findings are those that are interpreted as clinically 2 1996 PROCEEDINGS AMERICAN ASSOCIATION OF ZOO VETERINARIANS significant, but not the major contributing factor in the death of the animal. The findings were then sorted by individual, species, age-group, organ system affected, and disease category (infectious or non-infectious) for analysis of trends. Anesthesia and Restraint Many tapirs can be habituated to being touched and scratched. Some individuals will even lay down allowing physical examination and venipuncture. Temperaments of individuals vary greatly, however. One should exercise caution when working with any tapir that is being “scratched down” as they are capable of inflicting serious injury with their teeth. Anesthesia of tapirs over the last two decades has typically been accomplished using etorphine at approximately 10 µg/kg i.m. When etorphine became unavailable during the last several years, alternatives have become necessary. Some veterinarians have chosen to use carfentanil (20 µg/kg i.m.) alone or in combination with xylazine. Preliminary evidence from pulse oximetry monitoring indicates that potent opioids may result in poor oxygen saturation in tapirs. Currently, a promising regimen is a combination of butorphenol (0.15 mg/kg i.m.) and an "2-adrenergic agonist such as xylazine (0.3 mg/kg i.m.) or detomidine (0.05 mg/kg i.m.). Using this combination on 19 T. indicus and T. pinchaque, bradycardia was seen (30-55 bpm) but relative oxygen saturation measured by pulse oximetry was 90-95%. Good relaxation generally occurred after about 10 min. Ketamine (0.5 mg/kg i.v.) can be given if necessary for further restraint. The effects can be antagonized with yohimbine (0.2-0.3 mg/kg i.v.) and a narcotic antagonist such as naltrexone or naloxone, and recovery is generally rapid, smooth, and complete. Other combinations such as carfentanil/ketamine/xylazine21 and xylazine (0.8 mg/kg i.m.) with azaperone (0.8 mg/kg i.m.) followed by ketamine (0.5-1.0 mg/kg i.v.) have also been used successfully in tapirs. Azaperone has caused adverse reactions in horses (CNS excitement, etc), and some caution may be indicated in its use with tapirs. No adverse reactions were seen, however, in over 25 uses recorded from this survey. Direct intravenous induction with xylazine and ketamine can be accomplished on some individuals which are “scratched down” prior to venipuncture. Tiletamine-zolazepam has also been used with some success in tapirs in this survey at approximately 1-2 mg/kg (n=2).14 Sedation of tapirs to facilitate introductions or for minor standing procedures has been accomplished with azaperone (1.0 mg/kg i.m.) or less reliably with xylazine (1.0 mg/kg i.m.).10 Clinical Problems Clinical disease problems are summarized in Table 2. These clinical and disease correlates were determined from systematically reviewing medical records. Clinical Pathology 1996 PROCEEDINGS AMERICAN ASSOCIATION OF ZOO VETERINARIANS 3 Blood samples can easily be obtained from the medial saphenous or cephalic veins when the tapir is in lateral recumbency. These veins, however, tend to collapse or spasm while giving injections and during catheterization. The jugular