Department of Pathology, Smithsonian National Zoological Park, Washington, DC, USA; The Animal Dental Clinic, Vienna, VA, USA
Abstract
A condition characterized by serous atrophy of fat (SAF) has been reported as leading to peracute mortality in a number of giraffes at several institutions during the last three decades. These mortalities were originally attributed to insufficient protein and high-fiber diets but were also associated with stress, other nutritional imbalances, and infectious and toxic conditions.2,4 A recent report attributes similar giraffe morbidity and mortality to hypoglycemia and chronic energy malnutrition, mainly in younger giraffes.1
In four aging giraffes that died with SAF at the Smithsonian National Zoological Park, dental attrition and tooth and gingival abnormalities were consistent findings. Inflamed gingival pockets containing fibrous plant material were frequently noted on postmortem examination. High-resolution, postmortem dental films of a recent case showed advanced attritional changes, alveolar bone loss including periapical changes, and pocketing compatible with severe periodontal disease. The dental attrition and periodontal lesions are considered as major factors in the SAF syndrome of these giraffes.
Dental attrition and periodontal bone abnormalities of six captive and 15 wild giraffes were evaluated in skulls from the Smithsonian Institution collection. Only intact skulls from adult giraffes were examined. Markedly more advanced tooth attrition and evidence of greater dental disease was present in captive giraffes than in those from the wild (Table 1).
Table 1. Dental attrition in wild and captive giraffes
|
|
None
|
Mild
|
Moderate
|
Severe
|
|
Wild (n=15)
|
7
|
7
|
0
|
1
|
|
Captive (n=6)
|
0
|
0
|
3
|
0
|
In the wild, the giraffe, a selective browser, preferentially feeds on young shoots of Acacia spp. and other trees. Such shoots are high in digestible protein and have a relatively low fiber content.3,6 In zoo settings, giraffes are frequently maintained on a combination of hay and low-fiber ruminant pellets.5 The diets offered to captive giraffes may be suboptimal in substance and/or their physical form may lead to long-term adverse effects on teeth. Once oral disease has developed, mastication is compromised, and animals may suffer malnutrition even when offered an adequate diet.
Literature Cited
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2. Fowler ME. Peracute mortality syndrome in captive giraffe. JAVMA. 1978;173:1088–1093.
3. Hoffman RR, Mattern B. Changes in gastrointestinal morphology related to nutrition in giraffes Giraffa camelopardalis: a comparison of wild and zoo specimens. Int Zoo Yearbook. 1988;27:168–176.
4. Junge RE. Peracute mortality syndrome of giraffes. In: Zoo and Wildlife Medicine: Current Therapy 3. Philadelphia, PA: WB Saunders Company; 1993:547–549.
5. Lintzenich BA, Ward AM. Hay and pellet ratios: considerations in feeding ungulates. In: Nutrition Advisory Group Handbook, Fact Sheet 006. 1997:1–12.
6. Pellew RA. The feeding ecology of a selective browser, the giraffe (Giraffa camelopardalis tippelskirchi). J Zool Lond. 1984;202:57–81.