A meta-analysis of the mastitis vaccination efficacy in dairy cattle

Abstract

Background: Mastitis is the most important disease in dairy cattle with impact in welfare of animals and the economy of the dairy farming activity. Attempts have been made to produce vaccines to prevent the disease, however results have been dubious. Aim: The aim of this study was to evaluate the efficacy of the mastitis vaccination in dairy cattle by merging several trials to allow evidence synthesis. Methods: A list of publications with common methodological grounds was selected to allow a quantitative comparison in a meta-analysis with moderators. Results: A mixed methods model (P< 0.001), with four significant moderators was successfully fitted: “year of publication” (P< 0.001), “vaccination timing” (P< 0.01), “type of animal” (P< 0.001) and “vaccine fabrication” (P< 0.001). The model is homogeneous (P> 0.05), with the moderators explaining the variability. Efficacy decreases over time. Vaccines applied after calving show inefficacy (log risk ratio 1.72 [1.34, 2.21]), and applied before calving show reduced efficacy (log risk ratio 0,86 [0.72, 1.03]). Commercial vaccines don’t show efficacy (log risk ratio 1,07 [0.94, 1.22]). Self-fabricated vaccines show efficacy (log risk ratio [0.51, 0.94]. Conclusion: Full clarification of efficacy is not shown; however, if vaccination is used, must follow a pre-calving protocol. While not showing efficacy, the vaccination has demonstrated a reduction of the severity in clinical cases, rate of culling, and has increased the production of milk and milk solids. Vaccination may improve health and welfare but does not prevent the disease effectively; It must be seen as an additional tool to the traditional preventive measures.

Extended-Spectrum Beta-Lactamase-Producing Escherichia coli and Other Antimicrobial-Resistant Gram-Negative Pathogens Isolated from Bovine Mastitis: A One Health Perspective

“…Currently available vaccines are generally effective in reducing the severity of CM cases caused by E. coli and Klebsiella spp. [104]. The vaccine for E. coli is based on the J5 strain [105], while for Klebsiella spp., two products are available: one based on siderophore receptor proteins [106] and another containing a recombinant protein (YidR) [107].…”

“…The vaccine for E. coli is based on the J5 strain [105], while for Klebsiella spp., two products are available: one based on siderophore receptor proteins [106] and another containing a recombinant protein (YidR) [107]. Although vaccines are beneficial for reducing the severity of CM cases, increasing milk production, and decreasing the risk of culling, no evidence is available to support their use for preventing new intramammary infections by Gram-negative pathogens [104].…”

A Framework for Using Epidemiology in Animal Welfare Science

“…Examples of case-control studies in animal welfare sciences are Mata (2013) and Wylie, Collins, Verheyen, and Newton (2013). Mata (2013) produced a meta-analysis to evaluate the mastitis vaccination efficacy in dairy cows.…”

“…Examples of case-control studies in animal welfare sciences are Mata (2013) and Wylie, Collins, Verheyen, and Newton (2013). Mata (2013) produced a meta-analysis to evaluate the mastitis vaccination efficacy in dairy cows. In the different studies used in this meta-analysis cows developing the condition are the cases and those that do not are the controls.…”

“…For example, mastitis is one of the most important welfare issues in dairy cattle and if some studies show a clear advantage in the use of vaccines, some others do not. Mata (2013) produced a meta-analysis of case-control trials of mastitis vaccines where a slight advantage in the use of the vaccine is made evident. It is concluded that vaccines however, must not replace all the other practices and biosecurity measures used to prevent the disease; vaccines can be used with advantage, but only as an extra preventive measure.…”