Utility of tumor necrosis factor-α and interleukin-6 as predictors of neonatal mortality in white-tailed deer

Blood serum was collected between June 1990 and August 1992 from newborn white-tailed deer (Odocoileus virginianus) fitted with radiocollars. We measured serum concentrations of immunoreactive tumor necrosis factor-alpha. (iTNF-alpha) and immunoreactive interleukin-6 (iIL-6) to relate cytokine expression to probability of mortality during the first 21 days of life. Stepwise logistic regression indicated that iTNF-alpha, hemolytic complement, gamma globulins, gamma glutamyl transferase, and mass/length(3) could predict survival of white-tailed deer during the first 21 days of life with 90.9% accuracy. Univariate logistic regression did not show a relationship between serum concentrations of iTNF-alpha or iIL-6 and probability of mortality. However, fawns that died before 21 days of age tended to have greater levels of iTNF-alpha. (688.4 +/- 168.8 pg/ml) than survivors (412.9 +/- 81.2 pg/ml). Although these data suggest that iTNF-alpha may be a useful predictor of stress, additional research is needed to understand response of cytokines to neonatal stress and mortality and to elucidate their utility as indices.