27th Annual Meeting and Symposium of the
Desert Tortoise Council, March 22-24, 2002
Abstracts

Health Assessment of Neonate Tortoises: Problems With the Too Small

Elliott R. Jacobson
College of Veterinary Medicine, University of Florida, Gainesville, Florida 32610

Health assessment of both extremely large and extremely small vertebrates is problematic. With those extremely large animals, difficulties with health assessment center on access to the animal itself. Health assessment by its very nature requires direct contact with the animal. In many situations this may necessitate some form of manual or chemical restraint, something that is impractical to use with certain mega vertebrates such as large cetaceans, with small vertebrates, both those that are small as adults or small as neonates, the access issue may center around size related diagnostic limitations with the animal in hand.

As a group, chelonians are difficult animals to evaluate clinically. Many species are capable of withdrawing into the margins of their shell when threatened, becoming "bony boxes". Clinicians experienced in evaluating chelonians have devised methods for coaxing them out of their shells. For medium to small-sized chelonians, one method is to push in or gently touch the hind limbs, which often results in head extensions. Slow, deliberate movements will reduce fearful responses and retraction into the shell. Many tortoises will extend their forelimbs and head if tilted slightly downward, perhaps in an effort to avoid falling. Above all, examination of a frightened chelonian requires a good deal of patience.

The chelonian family Testudinidae consists of members ranging in adult size from 90 grams to some over 300 kg. Even for the largest tortoises, the small size of their neonates makes collection of certain samples and the use of certain diagnostic tools difficult or impossible. Neonate desert tortoises range in weight from approximately 25 to 35 grams vs. adult weight ranges of 800 grams or larger. The most common diagnostic tools used in evaluating chelonians include morphologic measurements, blood sampling for determining hematology, blood chemistry and serology, imaging for determining the status of internal structure, and samples from the nasal cavity, oral cavity and lower gastrointestinal tract. Biopsies may be needed from either external or internal structures. Regarding neonates, while morphologic measurements such as carapace length in the midline, carapace width and weight are easy to collect and may provide information relevant to health status, collecting biologic samples such as blood may be challenging, while others such as nasal washes may be very difficult to obtain.

As an investigator selectively works with a life stage of animal, techniques and procedures will develop and will subsequently be modified and refined to meet the restrictions imposed by the size of the animal being studied. While the resourcefulness and experience of the investigator may allow them to transcend some of the size related restrictions, certain diagnostic tools available for assessing health of adults may never be adaptable to neonates.