19 Dec 2022
Research carried out by SRUC Veterinary Services in conjunction with MSD Animal Health found antibodies across the national dairy herd in quarterly bulk milk tank serology.
Paul Imrie
Job Title
Salmonella Dublin is estimated to be present on 40% of British dairy farms, according to research carried out by SRUC Veterinary Services and MSD Animal Health.
Researchers recruited 401 dairy farms to represent England, Scotland and Wales, and performed quarterly bulk milk tank serology for S Dublin antibodies over a year.
In the study, published in Preventive Veterinary Medicine, the overall true prevalence of S Dublin antibodies across the national dairy herd was estimated at 40%1.
Nicole Baldry, dairy veterinary advisor at MSD, said the figures are significantly higher than many previous studies have shown2.
She said Salmonella needed to be more proactively considered as a potential differential diagnosis and an important part of herd health planning and biosecurity measures.
She added: “Salmonellosis can present with a wide range of clinical signs, including abortion, diarrhoea, pneumonia, septicaemia and even joint ills. It can also be present at a subclinical level, impacting milk yield and fertility. Therefore, Salmonella should always be on your differential diagnosis list.
“S Dublin is a very resilient bacteria and can survive for long periods of time in soil and stagnant water, as well as surviving temperature extremes3.
“Animals can also develop carrier status post-infection and shed during periods of stress, acting as a continual infection source for herds.”
S Dublin control is similar to that for Johne’s disease, and MSD has produced a Salmonella risk assessment tool to help vets work alongside farmers on biosecurity risks4.
Dr Baldry said because prevalence was worse than first thought, it is important vet practices work with farmers to increase awareness of the zoonosis.
She added: “A great place to start is by engaging with your farmers to start quarterly bulk milk testing, or screening serology in youngstock or breeding beef stock.
“Salmonellosis is dynamic; therefore, regular testing provides a more accurate on-farm picture.”
References
1. Henderson K et al (2022). Determining the prevalence of antibodies to Salmonella Dublin in dairy herds in Great Britain by quarterly bulk tank testing, Preventive Veterinary Medicine 208: 105,776.
2. Davison HC et al (2005). Prevalence, incidence and geographical distribution of serovars of Salmonella on dairy farms in England and Wales, Veterinary Record 157(22): 703-711.
3. World Health Organization (2018). Salmonella (non-typhoidal) Fact Sheet, www.who.int/news-room/fact-sheets/detail/salmonella-(non-typhoidal)
4. Nielsen LR and Nielsen SS (2012). A structured approach to control of Salmonella Dublin in 10 Danish dairy herds based on risk scoring and test-and-manage procedures, Food Research International 45(2): 1,158-1,165.
