Vaccination against Bacterial Mastitis in Sheep

Abstract

The objective of this review is to discuss the application of vaccination for the prevention of bacterial mastitis in ewes, performed within the frame of health management schemes in sheep flocks. Mastitis is a multi-faceted infection, caused most often by staphylococci; hence, special emphasis is given to staphylococcal mastitis, also given that most relevant studies refer to vaccinations against that infection. Studies regarding various vaccines have been performed; most studies refer to vaccination by using a vaccine making use of cell-free surface polysaccharides in various vehicles, bacterial unbound cells or bacterial cells embedded in their biofilm matrix. Vaccination against mastitis should be better performed during the final stage of pregnancy to allow protection of ewes from lambing and should be considered as one of many control measures for the prevention of the disease. The expected benefits of mastitis vaccination in sheep flocks include the following: (a) reduced incidence risk of clinical and subclinical mastitis, (b) reduced somatic cell counts, optimum chemical composition, absence of staphylococci in milk, (c) increased milk production, (d) reduced dissemination of mastitis-causing pathogens and (e) reduction of antibiotic use in flocks.

Keywords: Staphylococcus; health management; mastitis; milk production; sheep; udder; vaccination.

Figure 1

Proportion of flocks in which vaccination against staphylococcal mastitis was (V+) or was not (V−) applied, from the bulk-tank milk of which staphylococci were recovered (modified from Lianou et al. [45]) (bars indicate 95% confidence intervals).

Figure 2

Average annual milk production per ewe among flocks in which vaccination against staphylococcal mastitis was (V+) or was not (V−) applied (modified from Lianou et al. [45]) (bars indicate standard error of the mean).

Figure 3

Proportion of swab samples from the upper (massif-filled bars) or the lower (pattern-filled bars) part of milking clusters from which staphylococci were isolated, in flocks in which vaccination against staphylococcal mastitis was (V+) or was not (V−) applied (modified from Michael et al. [46]) (bars indicate 95% confidence intervals).