{"id":14,"date":"2024-08-13T22:32:24","date_gmt":"2024-08-13T10:32:24","guid":{"rendered":"https:\/\/sites.massey.ac.nz\/salmonella\/?page_id=14"},"modified":"2026-08-27T16:24:00","modified_gmt":"2026-08-27T04:24:00","slug":"salmonella-study","status":"publish","type":"page","link":"https:\/\/sites.massey.ac.nz\/salmonella\/","title":{"rendered":"Salmonella Study"},"content":{"rendered":"\n
Research Summary<\/strong> : In collaboration with dairy industry stakeholders, we conducted a study during the 2021-2022 & 2022-2023 dairy season to identify risk factors for salmonella<\/em> outbreaks on dairy farms.\n<\/div>\n\n\n\n

About the study<\/h2>\n\n\n\n

Massey University’s EpiCentre studies infectious diseases in livestock. <\/p>\n\n\n\n

This study aimed to help farmers manage the risk of salmonellosis on their farms, thus protecting animal welfare and preventing the signi\ufb01cant production impacts and costs associated with salmonella <\/em>outbreaks and risk’s to public health.<\/p>\n\n\n\n

A better understanding of salmonella <\/em>in dairy cattle will lead to improved prevention and control of outbreaks and better outcomes for public health in New Zealand by protecting farm workers, their families and the general public from salmonellosis.<\/p>\n\n\n\n

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Project team <\/font>
<\/strong>The project lead for this study is Dr Chris Compton.

Dr Chris Compton<\/strong>
PhD, MVS, BVSc., AFHEA
Senior Lecturer in Veterinary Epidemiology

Simon Verschaffelt<\/strong>
Technician<\/p>\n<\/div>\n<\/div>\n\n\n\n

Salmonella in New Zealand<\/h2>\n\n\n\n

Salmonella <\/em>causes outbreaks of scouring, abortion and death in dairy cattle. The effects of salmonella on-farm can be devastating, posing serious risk to health, productivity and welfare of affected animals. Salmonella <\/em>are also a leading cause of food poisoning in humans in New Zealand.<\/p>\n\n\n\n

The prevalence of Salmonella <\/em>outbreaks on New Zealand dairy farms has increased in the years from 2015 to 2020 , and new serotypes emerged and spread around the country. The same trend is observed in food-borne salmonellosis in humans.<\/p>\n\n\n\n

Ongoing national surveillance of veterinary diagnostics laboratory in the years 2015 – 2020 shows the emergence and rapid spread of Salmonella<\/em> serotypes Bovismorbificans, Give and Brandenburg in the cattle population of New Zealand (Figure 1).<\/p>\n\n\n\n

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Salmonella <\/em>trends 2010 to 2020
Figure 1: <\/strong>Laboratory confirmed cases of salmonella in cattle since 2010 (source: MPI)<\/p>\n<\/div>\n\n\n\n

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Foodborne disease surveillance conducted by ESR shows a mirroring trend in the number of diagnosed human cases of Salmonella<\/em> Bovismorbificans (Figure 2).<\/p>\n\n\n\n

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Count of human bovismorbificans cases
Figure 2:<\/strong> Notified human cases of Salmonella Bovismorbificans since 2007 (source: MPI\/ESR)<\/p>\n<\/div>\n\n\n\n

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Key results and recommendations for farmers from a National Study of Salmonellosis on NZ Dairy Farms<\/h5>\n\n\n\n

Chris Compton, EpiCentre, School of Veterinary Science, Massey University<\/p>\n\n\n\n


Background<\/strong><\/p>\n\n\n\n

NZ veterinary diagnostic laboratories reported a two- to three-fold increase in confirmed cases of salmonellosis on dairy farms between 2011 and 2021, and the emergence of Salmonella <\/em>serovars previously undetected in NZ. These patterns concerned the Ministry for Primary Industries (MPI) because of the impact of these cases on the welfare and productivity of dairy cattle, and the potential increased risk to public health from this zoonotic disease. MPI requested Massey University to undertake a nationwide study in the dairy seasons starting in 2021 and 2022 to describe the extent of salmonellosis outbreaks on dairy farms and to recommend control measures against them to farmers.<\/p>\n\n\n\n


How the study was run<\/strong><\/p>\n\n\n\n

Dairy vets and vet diagnostic labs helped us register 107 farmers on-line for the study whose animals had experienced one or more lab-confirmed cases of salmonellosis that were not Brandenburg serovar during the study. From these, we enrolled 53 \u2018case\u2019 farms with 10 or more animals affected and, with the help of the Fonterra On Farm Excellence (OFE) Operations Team, a further 118 unaffected \u2018control\u2019 farms were enrolled as a comparison group. All farms had spring- or split autumn-spring calving patterns and supplied a milk processor. Each eligible farmer provided further information about their farms and management practices by telephone interview with the researchers.<\/p>\n\n\n\n


Key study results<\/strong><\/p>\n\n\n\n