Vaccines for Bovine Mastitis are Safe and Efficacious in Laboratory Animals.

Mastitis is the most costly disease of dairy cattle and poses colossal economic losses to the farming community worldwide. The role of vaccination in controlling mastitis is of paramount importance and significantly reduces the use of antimicrobial agents. This study aimed at preparing and evaluating inactivated polyvalent mastitis vaccines containing bovine origin Staphylococcus aureus (tst), Streptococcus uberis (cpn-60 targeted STUB), and Escherichia coli (aggR) in a rabbit model. Four types of mastitis vaccines viz. formalin-inactivated plain polyvalent mastitis vaccine (FPPV), formalin-inactivated montanide adjuvanted polyvalent mastitis vaccine (FMPV), formalin-inactivated aluminum hydroxide adjuvanted polyvalent mastitis vaccine (FAPV), and formalin-inactivated montanide plus aluminum hydroxide adjuvanted mastitis vaccine (FMAPV) were prepared after confirmation for antigenicity and immunogenicity and evaluated for safety, side effects, challenge protection assay, sterility and humoral response in laboratory animals. Safety test showed no general adverse reactions to the vaccines when injected either into mice or rabbits or cow calves. Challenge protection studies revealed a significantly higher survival rate in vaccinated mice and rabbits compared to placebo groups. None of the vaccines when streaked onto culture media showed any growth indicating sterility of the vaccines. Repeated measures ANOVA was applied to compare mean O.D values of treatment groups for evaluation of humoral immunity. Serum ELISA O.D values against S. aureus (tst), Str. uberis (cpn-60 STUB) and E. coli (aggR) in vaccinated groups randomly inoculated i/m at thigh region @ 0.2 ml per rabbit were significantly higher (p<0.05) compared to control. Likewise, the humoral immune response of FAPV was highest followed in order by FMPV, FMAPV, and FPPV. It was concluded that newly-prepared polyvalent mastitis vaccines were safe to use, protective, and elicited a significant humoral immune response in rabbits. [ABSTRACT FROM AUTHOR]