Wairarapa vet Stu Bruere shares his extensive experience with Salmonella and together with MSD Technical Vets talk about managing Salmonella in sheep and the difference between Salmonella Hindmarsh and Salmonella Brandenburg.

sheep in the farm



  • Bacteria that live inside carrier animals (this is the main source of spread of Salmonella in New Zealand)
  • Can survive in the environment for weeks to months
  • Can infect all kinds of animals including humans (zoonotic disease)
  • Many different strains, two most prevalent in sheep:
    • Hindmarsh (primarily affects the gut)
    • Brandenburg (primarily causes abortions)
  • All types of Salmonella can cause outbreaks and deaths
  • Once Salmonella is established in a flock, it cannot practically be eliminated


Salmonella Hindmarsh (gut-affecting)

  • Has been in New Zealand since at least the late 1940’s
  • Sudden death is often the first sign of an outbreak
  • Outbreaks tend to occur in times of stress and deaths may continue sporadically for months
  • Seasonal disease, occurring from late summer through early winter (most often over mating)
  • Outbreaks most commonly seen in intensively managed and well-fed flocks
  • Case rates and mortality varies with flock immunity (average approximately 1% mortality) may accumulate to significant numbers
  • Occurs nationwide

Salmonella Brandenburg (abortive)

  • First outbreaks recorded in 1996
  • Causes late term abortions, sickness and death
  • Occurs in late pregnancy (early spring)
  • Outbreaks are sudden and escalate quickly
  • Up to 15% can abort and up to 50% of aborting ewes can die
  • As of 2021 only seen in the South Island


  • Salvexin®+B is the only Salmonella vaccination for cattle and sheep in New Zealand
  • It contains four strains of Salmonella: Hindmarsh, Brandenburg, Typhimurium and Bovismorbificans
  • For preventative vaccination give two shots in the first year (sensitiser & booster at least 4 weeks apart), 2nd shot should be at least 2-3 weeks before the risk period
  • Annual booster is required for ongoing protection
  • In the face of an outbreak:
    • Hindmarsh / Gut-affecting: Vaccination should be as early as possible to reduce stock losses
    • Brandenburg / Abortive: Vaccination is not recommended in the face of a Brandenburg outbreak unless advised by your vet
  • The most practical time to vaccinate for sheep farmers
    • Gut-affecting: between weaning and mating
    • Abortive: between rams in/out and scanning


  • Reduce stress (gradually introduce diet changes, lower stocking densities)
  • Manage birds and pests to keep them from spreading Salmonella
  • The most common way Salmonella is introduced to a farm is through healthy looking carrier animals (cattle, sheep etc.). Higher risk practices include:
    • Off-farm grazing
    • Intensive feeding
    • Purchasing/leasing stock
    • Shared boundaries/stock yards
  • Farms at risk of Salmonella should consider preventative vaccination


  • Practice strict biosecurity between affected mobs and other groups of sheep on the property
  • Involve your vet to take samples and confirm the diagnosis
  • Isolate sick animals/flocks
  • Monitor at-risk groups closely
  • Treating individual sick animals is not usually practical
  • Use strict hygiene practices when handling sick animals or working in their environment
  • Prevent vulnerable (old, young, pregnant or sick) people from having contact with animals and their environment
  • Use disinfectant and wear gloves, overalls and gumboots when handling at-risk animals
  • Contain and/or destroy contaminated material e.g. limit sick animal movement and bury foetuses, placenta and carcasses as soon as possible
  • For gut-affecting disease vaccinate all stock with Salvexin®+B as soon as possible under veterinary guidance (ensure a sensitiser & booster is given to previously unvaccinated animals and an annual booster given to all other animals)
  • For abortive form, spread sheep out and consider a preventative vaccination programme next year.

Don’t wait for Salmonellosis to strike.

salvexin + b

Vaccination reduces the impact of an outbreak and minimises production losses. Protect your flock with Salvexin®+B


  1. ACVM. (2018). A007886 Salvexin+B Leaflet.
  2. Baker et al. (2007). A recurring Salmonellosis epidemic in New Zealand linked to contact with sheep. Epidemiol Infect. 135:1. 76-83.
  3. Clark et al. (2004). Salmonella Brandenburg—emergence of a new strain affecting stock and humans in the South Island of New Zealand. NZVJ. 52:1. 26-36.
  4. Clark et al. (2002). Salmonella in animals in New Zealand: the past into the future. NZVJ. 50:3. 57- 60.
  5. Daly, S. (2019). Salmonella Brandenburg on Canterbury dairy farms. Proceedings of the Society of Dairy Cattle Veterinarians of the NZVA. 29-30.
  6. Gruenberg, W. (2019). Overview of Salmonellosis. Merck Veterinary Manual Online.
  7. Li, H., et al. (2005). Vaccination of pregnant ewes against infection with Salmonella Brandenburg. New Zealand Veterinary Journal. 53:6. 416-422.
  8. McGuirk, SM. & Peek, S. (2003). Salmonellosis in cattle: a review. Proceedings of the 36th Annual Conference of the American Association of Bovine Practitioners, Columbus Ohio.
  9. West, DM et al. (2009). Salmonellosis. The Sheep: Health, disease and production—3rd Edition. NZVA press. 322-327.


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top farmers know how text

Top Farmers Know-How provides a reference library of industry best practice in some key animal health management areas including mastitis, dry off, calf health, BVD, salmonella and campylobacter. We know that farmers and vets are busy people, so we’ve created resources in different formats and in bite-sized chunks to make it more flexible and accessible.