Comparison of in vitro tests for evaluation of passive transfer of immunoglobulins in giraffe (Giraffa camelopardalis)

Serum samples from captive giraffe (Giraffa camelopardalis) were tested to assess passive transfer of immunoglobulins using in vitro methods developed for domestic ruminants. Estimated immunoglobulin levels were compared usin g five tests (protein electrophoresis, total protein refractometry, zinc su lfate turbidity, glutaraldehyde coagulation, and sodium sulfite turbidity). A linear relationship was observed among total protein, gamma globulin (el ectrophoretic measurement), and immunoglobulin level based on spectrophotom etric measurement of zinc sulfate turbidity. Nonquantitative assays also de monstrated statistical correlation with the quantitative methods. Using cri teria similar to those established for domestic species, cutoff values for failure of passive transfer (FPT) were established for these tests in neona tal giraffe: 1) total protein <6.0 g/dl; 2) gamma globulin < 0.5 g/dl; 3) e stimated immunoglobulin level < 1,000 mg/dl (zinc sulfate turbidity); 4) gl utaraldehyde coagulation test negative; or 5) no visually detectable turbid ity in 16% sodium sulfite or Bova-S negative. Retrospective examination of the medical histories showed a strong statistical association between anima ls designated as having FPT and those that were removed from their dams bas ed on clinical assessment to be hand-reared. Application of these tests in the field should allow earlier detection and intervention for FPT in neonat al giraffe.