Vaccination against experimental staphylococcal mastitis in ewes

Area of Science:

• Veterinary immunology
• Bacterial disease prevention
• Sheep health

Background:

• Mastitis, an udder infection, poses a significant threat to dairy sheep productivity.
• Staphylococcus aureus is a primary pathogen causing mastitis in ewes.
• Effective vaccines are needed to control S. aureus mastitis and maintain milk yield.

Purpose of the Study:

• To evaluate the efficacy of a novel S. aureus vaccine in preventing mastitis in ewes.
• To assess the vaccine's impact on antibody production and milk yield following bacterial challenge.

Main Methods:

• Ewes were vaccinated twice during pregnancy with a vaccine containing killed S. aureus with pseudocapsule, toxoided beta haemolysin, and dextran sulphate adjuvant.
• Vaccinated and control ewes were challenged intramammary with five different S. aureus strains during lactation.
• Antibody titers (IgG1, IgG2 anti-pseudocapsule, anti-beta haemolysin) and milk production were measured.

Main Results:

• Vaccinated ewes exhibited significantly higher levels of circulating IgG1 and IgG2 anti-pseudocapsule antibodies and anti-beta haemolysin serum titers.
• The incidence of acute gangrenous and non-acute clinical mastitis was significantly lower in vaccinated ewes compared to controls.
• Milk production was significantly higher in vaccinated ewes than in controls after challenge with four out of five S. aureus strains.

Conclusions:

• The novel S. aureus vaccine effectively elicits protective immune responses in ewes.
• Vaccination significantly reduces mastitis incidence and improves milk yield in challenged ewes.
• This vaccine represents a promising strategy for controlling S. aureus mastitis in sheep populations.