Differences in immunocontraceptive responses in white-tailed deer (Odocoileus virginianus) and goats (Capra hircus)

Thirteen deer (Odocoileus virginianus) and three goats (Capra hircus) were given an initial immunization of 300 microg porcine zona pellucida (PZP) combined with 50 mg synthetic trehalose dicorynomycolate ml(-1) (STDCM) in drakeol i.m. in the semitendinosus and semimembranosus muscles. This immunization was followed by two booster injections of 300 microg PZP, 2 weeks apart. The vaccinations were made from the same purified batch of PZP and lot of adjuvant. All the doses were made at the same time and injected on the same day. The immune response was quantified by measuring serum anti-PZP IgG antibody concentration by ELISA. The results showed that the mean serum IgG concentration of the deer increased from 0.000 +/- 0.003 to 0.083 +/- 0.023 absorbance units, whereas in the goats the mean IgG concentration increase was from 0.044 +/- 0.019 to 1.245 +/- 0.774 absorbance units. Both the goats and deer showed a significant increase in IgG concentration (P < 0.05) after the final booster injection compared with preimmune serum. The final goat IgG concentration was significantly (P < 0.05) higher than that of the deer. If PZP and Freund's adjuvant are administered to deer, immunocontraception is achieved, but the IgG concentration in the deer in this study did not appear to be compatible with immunocontraception.