The present invention provides a composition and an improved single dose vaccine against E. rhusiopathiae and an improved single dose vaccine against E. rhusiopathiae andH. parasuis which provides one or more of the following: 1) confers effective immunity against E. rhusiopathiae and/or H. parasuis; 2) decreases the risk of developing clinical signs of E. rhusiopathiae and/or H. parasuis infection; 3) induces an immune response against E. rhusiopathiae and/or H. parasuis; and 4) has a DOI against E. rhusiopathiae and/or H. parasuis of at least four months. The composition or E. rhusiopathiae vaccine as well as the combined E. rhusiopathiae-H. parasuis composition or vaccine each includes a bacterial component of inactivated E. rhusiopathiae bacteria and a suitable adjuvant. The combined E. rhusiopathiae-H. parasuis composition or vaccine further includes an amount of H. parasuis antigen. The vaccines can be administered to animals in any conventional manner. The amount of the dose for intramuscular administr
