The term "treatment and/or prophylaxis" refers to the lessening of the incidence of the particular mycoplasma infection in a herd or the reduction in the severity of clinical signs caused by or associated with the particular mycoplasma infection. Thus, the term "treatment and/or prophylaxis" also refers to the reduction of the number of animals in a herd that become infected with the particular mycoplasma bacteria (= lessening of the incidence of the particular mycoplasma infection) or to the reduction of the severity of clinical signs normally associated with or caused by a mycoplasma infection in a group of animals which animals have received an effective amount of the immunogenic composition as provided herein in comparison to a group of animals which animals have not received such immunogenic composition.