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
Reprinted from: 1996 American Association of Zoo Veterinarians Proceedings. Nov 1996. Puerto Vallarta, Mexico. Pp. 1-11. Used by permission.
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 alpha-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.
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 years in captivity. They reach sexual maturity between 2 and 4 years. 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 for the Tapiridae.
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
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 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 ug/kg i.m. When etorphine became unavailable during the last several years, alternatives have become necessary. Some veterinarians have chosen to use carfentanil (20 ug/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 alpha-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 minutes. 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 disease problems are summarized in Table 1. These clinical and disease correlates were determined from systematically reviewing medical records.
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 vein is also difficult to catheterize but is available for large blood volume draw.
Analysis of hematology and clinical pathology values from MedARKS summaries showed no major differences between species of tapirs. In general, the values followed similar trends to those of other perissodactyls including horses. In our experience, plasma fibrinogen is particularly important for evaluating the presence of inflammation in tapirs and should be included with any hematologic evaluation. The following are approximate reference ranges for select values:
WBC: 5,000-16,000 cells/ul
Fibrinogen: 100-400 mg/dl
|BUN: 3-20 mg/dl|
Creatinine: 0.5-1.9 mg/dl
Glucose: 70-120 mg/dl
Sodium: 128-145 meq/l|
Potassium: 3.1-4.5 meq/l
Chloride: 85-110 meq/l
Calcium: 8.5-12.5 meq/l
Phosphorous: 3.2-7.0 meq/l
Pathology FindingsLITERATURE CITED
There were no apparent differences in disease patterns between species. Overall, noninfectious diseases accounted for two-thirds of the 108 mortalities in this survey, and infectious one-third. The greatest number of mortalities were in the neonatal and adult categories.
Most of the 28 deaths in the neonatal age category were stillbirths or deaths from undetermined causes (n=10), or factors relating to maternal behavior (e.g. maternal neglect and trauma, n=6). In addition, there were three cases of fatal aspiration pneumonia in animals being hand-reared due to maternal rejection. Other significant primary causes of mortality included two cases of accidental drowning, two cases of septicemia (one of which is speculative), one case of necrotizing bacterial enteritis, one case of ceco-colonic tympany, and one case of atresia ani.
In the adult age group, the largest proportion of mortalities fell into the gastrointestinal disease category (15/40), and most of these were noninfectious in etiology. Intestinal volvulus, gastric and colonic impactions, and colonic incarceration accounted for 6 of the cases. Oropharyngeal abscessation was another important problem, accounting for 3 cases. Bacterial cultures were seldom obtained in these cases, but the syndrome appears similar to oral necrobacillosis. The primary factors initiating these oral lesions were not clear from this survey, but oropharyngeal trauma would be an important consideration. Acute pancreatic necrosis/pancreatitis was found in three cases, which is a relatively high prevalence compared to domestic species. Eosinophilic enterocolitis was the primary finding in 2 cases. There was insufficient data to determine whether this condition was analogous to the eosinophilic gastroenteritis described in horses. One case of mandibular osteomyelitis (lumpy jaw) was identified. Infectious GI diseases were relatively uncommon in the adult population, with only one case of Salmonella enteritis identified.
Other significant diseases in the adult age-group included a case of Mycobacterium bovis pneumonia, 3 cases of bacterial septicemia, and a case of myocarditis due to encephalomyocarditis virus infection.
The most significant disease problems identified from the survey, arranged by age category, are summarized in Table 2.
Respiratory diseases were the most important cause of mortality overall. The prevalence of respiratory disease was relatively uniform across the various age-groups, but was uncommon in the aged-adult group. In contrast to the gastrointestinal disease category, most respiratory diseases had infectious etiologies. Most cases were of bacterial etiology, with septicemic/embolic pneumonias predominating over bronchopneumonia. The possibility of underlying viral infection in tapir bronchopneumonia cases has apparently not been investigated. The source of the septicemic/embolic pneumonias was not evident in most cases. There were also two cases of pulmonary tuberculosis due to Mycobacterium bovis, and one case of pulmonary coccidioidomycosis. The diagnosis of respiratory disease in Malayan tapirs was confounded by the misinterpretation of pleural adhesions as evidence of pleuritis or pneumonia in a number of instances. Noninfectious respiratory diseases included two aspiration pneumonias which occurred during anesthesia. Three other restraint-related deaths occurred (asphyxia, unexpected death under anesthesia, and hyperthermia during transport).
Medical Management Recommendations
Tuberculosis has been reported repeatedly in the literature24 and seen in other animals in this survey. Therefore, it is important to develop reliable diagnostic tests for monitoring tapirs for this disease. However, antemortem diagnostic tests have not been validated in tapirs, and interpretation of results is therefore difficult. Nevertheless testing should be performed particularly prior to relocation of an animal. Tuberculin skin testing using an M. bovis antigen (ppd bovis, USDA) in the inguinal region near the nipples may be the preferred site. Cervical skin testing is difficult because of the thick nature of the cervical skin. Tapirs lack a true tail fold, but skin around the perineum can be used.
The BTb test, which includes the lymphocyte transformation and ELISA tests, was developed for testing whole blood of cervids for tuberculosis and may be a useful adjunct to antemortem diagnosis. Again, since this test is not validated for tapirs, the results may not be interpretable. Nevertheless, if results on these tests or others suggest an exposure to mycobacteria, it may be worth pursuing further diagnostics such as comparative tuberculin testing, thoracic radiography, and mycobacterial culture of gastric or tracheal samples.
Diseases for which vaccinations are available have not been documented in tapirs. Some authors have recommended vaccination for equine encephalitis viruses, tetanus, and other clostridial diseases (Kuehn, Ramsay).
Pregnancy may be difficult to determine in tapirs using conventional means. Breedings are usually not observed, and even advanced pregnancy may not be obvious. Pregnancy can be detected by means of urinary and fecal steroid analysis.4,17 Transabdominal ultrasound has been used to diagnose and monitor pregnancy in Tapirus bairdi (R. Wack, personal communication).
Currently, a moratorium has been placed on the breeding of Tapirus terrestris in North American collections. As a result, some institutions have devised methods of contraception for this species. Castration, melengestrol acetate implants, medroxyprogesterone acetate (DepoProvera, Upjohn) injections at (2.5-5.0 mg/kg), and altrenogest (Regumate, Hoechst-Roussel) are beginning to be used in tapirs. Other options including porcine zona pallucida vaccine have not yet been evaluated in Tapirus.
DIET AND NUTRITION
Due to the similarities of gastrointestinal tract anatomy, the domestic horse is typically used as a model for all tapir species when developing dietary guidelines. When fed diets of alfalfa or timothy hay, the comparative digestibility of cellulose by three tapir species and a domestic horse was 41% and 47%, respectively. Digestibility of hemicellulose by the three tapir species and horses was 45% and 52%, respectively.8,11,26
Species with a limited stomach volume consume several small amounts of feed frequently over time, instead of one large quantity within a shorter time period. Horses offered large quantities of food in a single feeding may demonstrate labored breathing and rapid fatigue.5 Severe overeating has been implicated as a factor leading to colic, ruptured stomach, or founder in domestic horses. As a result, it is usually recommended that herbivores with hindgut fermentation be fed two to three times a day. Frequency of feeding has no apparent effect on digestibility of the feed.12
Tapirs should be fed using strategies similar to those used for other perrisodactyls. Their diet typically includes both forages and pelleted feeds. Hay is the most common forage fed to tapirs, although browse and pasture may constitute a significant portion of the captive tapir's diet, based upon the geographic location of the holding facility and the characteristics of the enclosure. Current studies examining the feeding behavior and foods selected by free-ranging Baird's tapirs in Cost Rica may provide additional insight to the nutrient concentrations in plants selected by wild tapirs.7 Pelleted herbivore feeds, typically based on alfalfa, are most commonly fed to captive tapirs. Different pellets are formulated to be fed at different rates (e.g., complete feeds versus supplements). A herbivore pellet formulated for grazing ungulates, which contains 15% crude protein, 0.7% lysine, and 21% acid-detergent fiber (DMB), along with alfalfa hay (18% crude protein, 30% acid-detergent fiber) (DMB) has been successfully used for feeding all species of tapirs.
There is some preliminary clinical data which suggest tapirs may have a unique metabolic requirement regarding copper. Mean serum copper in samples collected across all four species of tapirs were 0.21 µg/ml (n=22). Dietary copper concentrations appear adequate, when compared to guidelines for horses.22 The interaction of copper with other trace elements, including iron, zinc, sulfur and molybdenum may contribute to these clinically low values. The significance of these serum copper concentrations has yet to be determined.
Limited published information is available regarding the composition of maternal milk in tapirs. A single citation, with no reference to stage of lactation, reports the milk of the Malayan tapir is 15.7% solids. The solids fraction of that sample contained 36.3% crude protein, 21.7% ether extract (crude fat), and 42.0% lactose.16 The solids, crude protein, and ether extract concentrations from that reference are relatively higher than the same values for milk from domestic horses.27 The carbohydrate (lactose) fraction of the tapir milk sample is relatively lower than that of the horse.
The mean birth weight of female, Malayan tapir calves is 10.1 kg (n=4).1 The absolute rate of growth in these mother-reared calves was 1.33 kg/d from 0-29 d. Solids are first consumed at 14 d (range 8-19 d) (n=3). Transfaunation, accomplished by feeding strained feces from normal tapirs, has been useful in our experience to encourage growth of normal flora in young tapirs raised in isolation.
Neonatal examinations can be useful for assessing general health and determining the success of immunoglobulin transfer from the dam. It can be a challenge to collect blood from a struggling newborn tapir. The jugular vein is usually the best site for venipuncture in a neonate. Glutaraldehyde coagulation performed on serum will test for the presence adequate immunoglobulins in tapirs. In cases where the calf fails to nurse, it is often possible to encourage the female to lie down and then place the calf on the nipple.3 Neonatal isoerythrolysis has been observed in a Baird's tapir (R. Wack, pers. comm.). Greater effort needs to be directed toward solving management problems related to failure of the maternal-infant bond, and to identifying causes of stillbirths and early neonatal deaths.
PRE-SHIPMENT PROCEDURES -GUIDELINES
Preshipment testing is recommended for any tapir relocation. Relocation may include captive or free- ranging transfers such as reintroduction, translocation, and relocation from one institution to another. Quarantine of individuals should be performed before exposure to animals at the new location. The risk of disease concern may vary greatly depending on the circumstances, and should be factored into any pre-shipment testing strategy. Zero-risk is a desired but seldom practical goal. Governmental regulations need to be considered, but often are not related to actual disease susceptibility or test validity. Interpretation of results may be difficult in some cases due to lack of scientific validation of the tests for tapirs.
The following are recommended guidelines to aid in decision making by veterinarians together with animal managers and biologists faced with planning the safe transfer of a tapir: 1) fecal sample for parasites particularly nematodes and protozoans, 2) fecal culture especially for Campylobacter and Salmonella, 3) tuberculin skin testing using ppd bovis intradermally in a soft skin area such as in the inguinal area near the nipples, 4) BTb testing at time of tuberculin testing or reading, 5) blood sample for complete blood count, including fibrinogen, and serum chemistries, 6) vaccination if indicated regionally for tetanus, other clostridial diseases, or equine encephalitis, and 7) a complete physical examination including oral, ophthalmic, and foot pad inspections.
Funding for this survey was provided by a Conservation and Research grant from the Zoological Society of San Diego. We thank Ms. Sherri Michelet for data entry into MedARKS and the bibliography. We appreciate the review of relocation guidelines by Drs. D. Armstrong, S. Citino, and J.A. Teare. We particularly appreciate the support from veterinarians and their staffs from the following institutions who provided us with medical and pathology records for this survey: Audubon Park and Zoological Garden, Bronx Zoo-Wildlife Conservation Center, Brookfield Zoo, Chaffee Zoological Gardens of Fresno, Cheyenne Mountain Zoological Park, Cincinnati Zoo, Cleveland Metroparks Zoo, Columbus Zoological Gardens, Dallas Zoo, Denver Zoological Gardens, Detroit Zoological Park, Houston Zoological Gardens, Lincoln Park Zoological Gardens, Los Angeles Zoo, Memphis Zoo, Lowry Park Zoological Gardens, Metro Washington Park Zoo [Oregon Zoo], Metropolitan Toronto Zoo, Miami Metrozoo, Milwaukee County Zoo, Minnesota Zoological Garden, National Zoological Park, Oklahoma City Zoological Park, Omaha's Henry Doorly Zoo, Reid Park Zoo, St. Louis Zoological Park, San Antonio Zoological Gardens, San Francisco Zoological Gardens, Santa Barbara Zoological Gardens, Sedgwick County Zoo, Woodland Park Zoological Gardens.
|Clinical Sign or
|Colic||1. bacterial entrocolitis
2. intestinal accidents
3. sand impaction
|Important to be able to quickly differentiate medical from surgical problems. Treatment and prevention for sand impaction can include psyllium added to the diet on a routine basis.|
|Corneal cloudiness||1. excessive light exposure
|Etiology not known. Most common in T. indicus. Sometimes associated with corneal ulceration.|
|Death, neonatal||1. FPT/septicemia
|Neonatal mortality will be high unless a suitable birthing environment is available. Neonates born to primiparious females may need assistance in getting to nurse. Male should be removed and pools drained for 1-3 wks after birth.|
|Death, sudden||1. encephalomyocarditis virus
2. intestinal accidents
|Not many other causes of sudden death in healthy tapirs.|
|Dermatitis, general||1. sarcoptic mange
2. dermatophyte (Microsporum sp.)
|Both reported in European literature, but not seen in this survey 9, 25|
|Diarrhea, chronic Vomiting||1. inappropriate diet
2. Bacterial/protozoal enteritis
3. eosinophilic enterocolitis
|Minimize fruit in diet. Bacterial enteritis most frequently due to Salmonella, Campylobacter. Giardia also may cause diarrhea. Ciliates probably do not. Chronic cases may require repeated fecal cultures and endoscopic GI biopsies.|
|Dorsal skin vesicles and sloughs/collapsing||1. vesicular skin disease||Cause of this syndrome unknown. See Finnegan.6|
|1. pulmonary tuberculosis
2. bacterial pneumonia
4. laryngeal abscess
|These signs may be indicative of life-threatening disease.|
|Lameness, acute||1. overwear of foot pads
2. overactivity during introduction
3. hard substrate
|Severe pad ulcerations can develop when animals become overactive. A hard substrate or continuously wet concrete can also cause foot problems.|
|Lameness, chronic||1. degenerative joint disease
2. chronic foot pad ulcers
|DJD common in older animals. Should be differentiated from foot pad disease.|
|Mandibular swelling||1. molar apical abscess
2. mandibular osteomyelitis
|Common and difficult to treat successfully. Often becomes chronic problem. Occasionally a cause of death when osteomyelitis leads to systemic disease.|
|Nasal discharge||1. guttural pouch infection
2. bacterial rhinitis
|Although nasal discharge may represent only upper airway disease, it may also indicate more serious lower airway disease. See above under dyspnea and coughing.|
|Rectal prolapse||1. diet, stress
|Once a common problem in tapirs, but less frequently seen now.|
Cloudy, chalky urine
|1. genitourinary tract infection/estrus
2. normal uninary calcium excretion
|Best differentiated by urinalysis or cytology.|
|Weight loss, chronic||1. renal failure
2. dental disease
4. chronic bacterial pneumonia
|Pulmonary tuberculosis has been seen repeatedly in captive tapirs, and frequently reported in the literature.24|
|Mycobacterium bovis infection|
|Mandibular osteomyelitis (lumpy jaw)|
|Restraint related death**|
<30d), J=juvenile (30d-1y), AS=subadult (1-4y), AA=aged adult (