Method of increasing the effectiveness of oral vaccination for swine dysentery

The method of increasing the resistance of field-raised swine to dysentery infection, comprising a sequence of parenteral and oral administrations which are carried out before the swine contract the infection, characterized by:

• (a) first parenterally administering to the swine an injectable cell concentrate containing a virulent isolate of killed cells of Treponema hyodysenteriae at least one injection being given per animal and each injection containing at least 2 milligrams (dry basis) of said cells;
• and
• (b) not less than 5 days after said animals have received the first of said parenteral injections beginning a series of oral administrations of enteric-coated pellets containing concentrated killed cells of a virulent isolate of Treponema hyodysenteriae, said oral administrations being given at least one every 24 hours for a period of at least 5 days, and each of said oral administrations providing at least 3 milligrams (dry basis) of said cells.