The extraction of cobalt from chloride medium using two organophorous extractants: bis (2,4,4-trimethylpentyl) phosphinic acid (Cyanex 272) and di-(2-ethyl-hexyl) phosphoric acid (D2EHPA) was studied. The important parameters governing the extraction of cobalt have been studied. Foot and mouth disease (FMD) is a contagious disease of domesticated and wild cloven-hoofed animals with serious losses of production and prenatal mortalities. Vaccination is widely used to control FMD in Egypt. This study aimed for comparative evaluation of an inactivated trivalent FMD vaccine with either using montanide oil ISA 206 or 201 adjuvants that were applied in sheep. The prepared vaccines proved sterile and safe. Neutralizing antibodies against serotypes O, A and SAT2 FMD virus reached the protective titers at the 3rd and 2nd week post vaccination (wPV) for sheep vaccinated with FMD vaccine based on ISA 206 and 201 oil adjuvants, respectively. These antibody titers persisted in protective level till 32 wPV against serotypes A and SAT2 FMD virus and till 36 wPV against serotype O for sheep vaccinated with FMD vaccine based on ISA 206 oil adjuvant. Neutralizing antibody titers against serotypes O, A and SAT2 FMD virus persisted in protective level for 40 wPV for sheep vaccinated with FMD vaccine based on ISA 201 oil adjuvant. These results were confirmed using ELISA. Evaluation of FMD virus-specific cell-mediated immunity using XTT assay showed high lymphocyte proliferation expressed by optical density from the 3rd day post vaccination (dPV), increased to reach a maximum value 2nd wPV and persisted in a high level till 9th wPV for FMD virus types O, A and SAT2 inducers for both sheep groups vaccinated with inactivated trivalent FMD vaccine either using montanide oil ISA 206 or 201 adjuvant. Finally, it was concluded that the inactivated trivalent FMD vaccine with ISA-201 oil adjuvant was superior than the vaccine with ISA-206 adjuvant in giving earlier and longer duration immune response in vaccinated sheep < /p>