SERUM FERRITIN CONCENTRATION IS NOT A RELIABLE BIOMARKER OF IRON OVERLOAD DISORDER PROGRESSION OR HEMOCHROMATOSIS IN THE SUMATRAN RHINOCEROS (DICERORHINUS SUMATRENSIS).

The aim of this study was to determine if ferritin is a reliable biomarker of iron overload disorder (IOD) progression and hemochromatosis in the Sumatran rhinoceros (Dicerorhinus sumatrensis) by developing a species-specific ferritin assay and testing historically banked samples collected from rhinos that did and did not die of hemochromatosis. Ferritin extracted from Sumatran rhino liver tissue was used to generate antibodies for the Enzyme Immunoassay. Historically banked Sumatran rhino serum samples (n = 298) obtained from six rhinos in US zoos (n = 290); five rhinos at the Sumatran Rhino Conservation Centre in Sungai Dusun, Malaysia (n = 5); and two rhinos in Sabah, Malaysia (n = 3) were analyzed for ferritin concentrations. Across all US zoo samples, serum ferritin concentrations ranged from 348 to 7,071 ng/ml, with individual means ranging from 1,267 (n = 25) to 2,604 ng/ml (n = 36). The ferritin profiles were dynamic, and all rhinos exhibited spikes in ferritin above baseline during the sampling period. The rhino with the highest mean ferritin concentration did not die of hemochromatosis and exhibited only mild hemosiderosis postmortem. A reproductive female exhibited decreases and increases in serum ferritin concurrent with pregnant and nonpregnant states, respectively. Mean (±SD) serum ferritin concentration for Sumatran rhinos in Malaysia was high (4,904 ± 4,828 ng/ml) compared to that for US zoo rhinos (1,835 ± 495 ng/ml). However, those in Sabah had lower ferritin concentrations (1,025 ± 52.7 ng/ml) compared to those in Sungai Dusun (6,456 ± 4,941 ng/ml). In conclusion, Sumatran rhino serum ferritin concentrations are dynamic, and increases often are not associated with illness or hemochromatosis. Neither a specific pattern nor the individual's overall mean ferritin concentration can be used to accurately assess IOD progression or diagnose hemochromatosis in this rhino species.

Sexual maturation in the Sumatran rhinoceros (Dicerorhinus sumatrensis).

To help save the Sumatran rhino from extinction, the captive breeding program must capitalize on each rhino's reproductive lifespan. Doing so requires knowing when calves are sexually mature. The goal of this study was to monitor physiological changes associated with sexual maturation in two captive born calves (one male and one female) to determine the approximate age of maturity for both sexes of this species. Fecal testosterone metabolites were monitored in the male calf from 6 months to 7 years of age, and fecal pregnane metabolites were measured in the female calf from 6 months to 5.5 years of age. In addition, rectal ultrasonography was employed to monitor changes in ovarian activity from 2 to 5.5 years of age. The male calf's fecal testosterone concentrations reached levels comparable to those detected in samples from adult males when he was 6-6.5 years of age. The first pre-ovulatory sized follicle was observed on the ovaries of the female calf when she was 4.75 years old, but fecal pregnane metabolite concentrations only reached maximum mean concentrations and variability when she was 5-5.5 years of age. Results from this study indicate that male and female Sumatran rhino calves are sexually mature at 6-6.5 and 5-5.5 years of age, respectively.

Urinalysis in three species of captive rhinoceros (Rhinoceros unicornis, Dicerorhinus sumatrensis, and Diceros bicornis).

This study reports urinalysis values for three species of captive rhinoceros (Rhinoceros unicornis, Dicerorhinus sumatrensis, and Diceros bicornis) and evaluates individual and species differences. Repeated urinalysis was conducted on 11 individuals to establish normal reference ranges. Although no individual or species differences existed in urinary values for pH, all species differed in specific gravity. Rhinoceros urine demonstrated many physical and chemical properties similar to that of the horse, but reliability of this comparison was limited. Urinary pH in the rhinoceros was within range of that established for the horse and other large herbivores. However, all rhinoceros species exhibited urinary specific gravities below the lower limit of the normal equine reference range. Comparative urinalysis using an outside laboratory source confirmed the results of this study and illustrated the value of conducting in-house analysis. These results are the first data available on reference ranges for urine parameters in the greater one-horned, Sumatran, and African black rhinoceros and provide a useful diagnostic tool for the veterinary care of individuals in captivity.