The objective of this study was to evaluate effectiveness of Ovalbumin-LHRH-7 (OL) protein when injected in crude, purified, free or encapsulated forms and using a single vaccination protocol along with CpG, inulin and saponin adjuvants. Fifty six C57BL/6 mice in seven groups (n=8) received various treatments and doses: Group 1 was control; Group 2 and 3 were injected twice with purified or crude OL protein, respectively, 4 wks apart. Group 4 and 5 were injected only once with purified or crude OL protein, respectively. Group 6 was injected only once with a mix of purified OL protein and encapsulated purified OL protein. Group 7 was injected only once with a mix of crude OL protein and encapsulated crude OL protein. There was an immunization effect observed on the I-125 LHRH % binding (P<0.05). Antibodies (Abs) against LHRH were identified on week 5 of immunization in groups 2, 3 and 4. Boosting at week 5 caused a significant increase in LHRH antibody (Ab) concentrations in groups 2 and 3. Numbers of pregnant animals and prengnancy rates were suppressed in all treatment groups at various degrees (P<0.05). Numbers of pups born were affected by immunization (P<0.05). Concluding, immunization with OL protein generated either biological or both immunological and biological effects in the most of treatment groups. The study confirmed the earlier findings that purified OL protein with CpG adjuvant is effective in inducing immune response and suppressing reproductive functions. However, the original idea that the non-capsulated antigen/adjuvant mix would work as primary injection, while encapsulated counterpart would mimic booster injections in a single vaccination protocol could not be confirmed in this study. Further studies to determine affecting factors for single-injection LHRH immunization are needed.