Immunization and
immunotherapy for
mastitis are active areas of investigation. The past decade has seen development of effective and economical R-mutant
vaccines for gram-negative
mastitis. These
vaccines doubtless will prove beneficial on well managed dairies that have eradicated contagious
mastitis pathogens. Development of
vaccines for other
mastitis pathogens has been noticeably slower. A commercially available Staphylococcus aureus
vaccine appears to reduce the frequency and severity of clinical episodes, but probably has minimal impact on the incidence or prevalence of
infection. This product has not been extensively studied. The recent recognition of
virulence factors produced in vivo by Staphylococcus aureus may provide a breakthrough in the development and production of Staphylococcus aureus
vaccines. Bacterins employing this principle presently are not commercially available, however. In the case of all contagious
mastitis pathogens (Streptococcus agalactiae, Staphylococcus aureus, and Mycoplasma spp.), traditional control and eradication efforts (teat dip, dry cow
therapy, culling programs) likely will prove preferable to long-term immunization. Ongoing research may provide more efficacious
vaccines for these
mastitis syndromes.
Immunostimulants are an active area of research. Although leukopoietic factors appear promising as
immunostimulants, no compound has clearly demonstrated efficacy in either the prevention or treatment of
bovine mastitis.