Back to search

FFL-JA-Forskningsmidlene for jordbruk og matindustri

Increasing sustainability of Norwegian food production by tackling streptococcal infections in modern livestock systems

Alternative title: Increasing sustainability of Norwegian food production by tackling streptococcal infections in modern livestock systems

Awarded: NOK 4.4 mill.

Project Number:


Application Type:

Project Period:

2018 - 2022


Partner countries:

Udder infections of cows caused by the bacterium Streptococcus dysgalactiae have more than doubled in the last 15 years. At the same time, outbreaks of infectious arthritis in lambs caused by the same bacterium have become more frequent. The infections cause production losses, reduce animal welfare and lead to increased antibiotic usage. This project started in 2018, with funding from FFL/JA, Animalia and TINE SA, and finished in April 2022. The goal was to reduce the incidence of streptococcal infections in sheep and dairy cows in Norway. The project has provided new knowledge about risk factors for S. dysgalactiae infections, transmission pathways and sources of the bacterium. This can help improve infection disease control, and improve animal health. One of the first tasks in the project was to improve methods for detecting S. dysgalactiae in complex sample material, such as environmental samples. This work resulted in a selective cultivation method as well as a new PCR method. Several thousand specimens were collected from sheep flocks and cattle herds to find out what are the main sources of S. dysgalactiae. The bacterium was most frequently found on the skin and wounds of animals, and in cattle herds it was also widespread in the environment. Bacterial isolates from different herds and from both animal species were whole genome sequenced. The analyses suggest that some bacterial variants are adapted to the different animal species. Genetically related bacterial strains were found in geographically distant farms. There was no evidence that certain bacterial variants caused more serious illness. In two different surveys to sheep farmers and dairy farmers, respectively, we investigated whether there are specific risk factors for streptococcal infections in lambs and dairy cows. TLarge sheep flocks with many lambs born per ewe, plastic grids on floors and infected ear tag wounds increased the risk of outbreaks of arthritis in lambs. For cattle, free stall housing, solid concrete flooring and parlour milking were associated with a higher risk of high incidence of S. dysgalactiae mastitis in the herd. A whole cell vaccine for sheep was tested against S. dysgalactiae. The vaccine will be assessed both with regard to antibody response in vaccinated animals and disease occurrence in vaccinated herds. Preliminary studies indicate that the vaccine has a protective effect as long as a large proportion of the ewes are vaccinated. An ELISA method was also established to detect antibodies from vaccinated sheep, and the method was able to demonstrate that the animals had an antibody response to the bacterium after vaccination. The composition of microorganisms (microbiota) in bulk milk affects the quality of the final product. In this project, studies of the milk microbiota were carried out it was found that changes in the bulk milk microbiota are influenced by the occurrence of udder infections in the herd. However the microbiota remains relatively stable over time at the herd level.

Prosjektet har gitt innsikt i hva som er risikofaktorer for utbrudd med S. dysgalactiae hos sau, og for høy forekomst av S. dysgalactiae jurbetennelse i melkekubesetninger. Prosjektet har også identifisert hva som er kilder til bakterien i besetningene. På bakgrunn av funnene har prosjektet kunne gi konkrete råd om tiltak til sauebønder og til melkebønder om hvordan å redusere problemer med streptokokkinfeksjoner. Dette vil med stor sannsynlighet kunne bidra til å bedre dyrehelsen i besetningene. Rådene er distribuert via Animalia (til sauebønder) og via TINE SA (til melkeprodusenter).

Streptococcal infections compromise welfare, reduce production and increase antibiotic usage in food-producing animals. In parallel with modernization of management and housing, Streptococcus dysgalactiae intramammary infections (IMI) in dairy cows and septic arthritis in lambs have increased. In sheep, outbreaks of septic arthritis have been observed with 40 % of the lambs affected and treated with antibiotics. The main objective is to reduce S. dysgalactiae infections in dairy cows and meat sheep in Norway. Sources, transmission routes, and risk factors for S. dysgalactiae infections will be investigated in order to identify control measures. The efficacy of S. dysgalactiae vaccination of ewes to prevent septic arthritis in lambs will be tested. Methods for detection of S. dysgalactiae will be improved. Sources, transmission routes and risk factors for S. dysgalactiae infection in sheep and cows will be investigated. Whole genome sequencing of bacterial isolates will be used to detect transmission routes and determine virulence, contagious behavior and host specificity of the bacteria. Whole cell vaccines give good immune responses in sheep, and are a starting point for vaccination against septic arthritis in lambs. The project will refine and test a whole cell vaccine to reduce the prevalence of septic arthritis. The microbial composition of milk affects the quality of the final milk product. The microbiota of bulk milk will be investigated by high throughput sequencing to find out how the microbiota is influenced by S. dysgalactiae IMI and management factors. The project will promote sustainability of Norwegian food production by improving animal health and welfare, and reducing antibiotic usage. The industries define streptococcal infections as a significant and increasing challenge. Knowledge on S. dysgalactiae epidemiology, transmission and environmental persistence will improve prevention of this contagious pathogen in modern production systems

Funding scheme:

FFL-JA-Forskningsmidlene for jordbruk og matindustri