The invention provides an improved Mycoplasma hyopneumoniae bacterin vaccine composition, which advantageously provides immunity from infection after a single administration. The composition comprises an inactivated Mycoplasma hyopneumoniae bacterin and an adjuvant mixture, which, in combination, provide immunity from Mycoplasmahyopneumoniae infection after a single administration, and elicit an immune response specific to Mycoplasma hyopneumoniae bacterin and including cell-mediated immunity' and local (secretory IgA) immunity. In a preferred embodiment, the adjuvant mixture comprises an acrylic acid polymer, most preferably Carbopol, and a mixture of a metabolizable oil such as one or more unsaturated terpene hydrocarbons, preferably squalene or squalane, and a polyoxyethylene-polyoxypropylene block copolymer such as Pluronic®. The vaccine composition may optionally include a preservative, preferably thimerosol and/or EDTA. In another embodiment, the invention provides an improved Mycoplasma hyopneumoniae bacterin vaccine composition, which advantageously provides immunity from infection after a single administration, and comprises an inactivated Mycoplasma hyopneumoniae bacterin and an adjuvant or adjuvant mixture, which, in combination, provide immunity from Mycoplasma hyopneumoniae infection after a single administration, and elicit an immune response specific to Mycoplasma hyopneumoniae bacterin and including cell-mediated immunity and local (secretory IgA) immunity, in combination with other vaccine components.
