Ovine mastitis is a significant production-limiting disease and the most important welfare problem of sheep, across all production types and all management systems. Control is based in a combination of management techniques, with little evidence available regarding applied immunoprotective measures. Objective of the experiment was to study the efficacy of a novel vaccine for protection of ewes against experimentally induced staphylococcal mastitis and to evaluate potential effects in milk yield of ewes. The vaccine induces antibodies against the poly-N-acetyl β-1,6 glucosamine exopolysaccharide, the main component of the extracellular biofilm matrix of staphylococci, and acts in preventing slime production and consequently biofilm formation by these organisms, which are a principal causal agent of ovine mastitis.

The results confirmed the protective effect of the vaccine, as evidenced by the milder clinical signs, the earlier resolve of the disease and the smaller decrease in milk yield compared to results of challenge of unvaccinated ewes.