Salmonella (Salmonellosis) is a disease of cattle, sheep, birds and other species. It is essentially a disease of the gastro-intestinal tract but can become a generalized infection. The disease can be characterized by low to high infection rates, low to high death rates, and carrier animals showing no symptoms. All ages of stock can be affected.

The Cause

There are a number of different Salmonellas including several different strains of Salmonella typhimurium, Salmonella bovis morbificans, Salmonella mbandka, and other Salmonellas. There has been one recorded outbreak of Salmonella brandenburg in dairy cattle in the South Island. Recent cases have been associated with high levels of supplementary feeding (meals such as kibbled maize and wheat – not palm kernel), Mineral Boost, and farmers mixing their own minerals.

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The Course of the Disease

Most outbreaks of Salmonella occur in well fed, well managed herds that are in good condition. Most outbreaks of Salmonella in cattle occur in farms where Salmonella has been diagnosed on the farm in the past. Therefore it is likely that there are carrier animals in the herd. For some reason that is not particularly clear, there is a change in conditions in the rumen (first stomach) contents through feed or mineral supplementation that changes the flora of the rumen, and creates conditions that favour multiplication of the Salmonella.
The first sign in a herd that the farmer is likely to notice is a fall in expected milk yield. This is followed by individual cows with a high temperature, and then diarrhea is seen. The diarrhea is typical for Salmonella in that the faeces are runny, and blood stained or brown.
Recent outbreaks have caused losses in production, treatment costs and deaths up to $150,000.


Early diagnosis and treatment will reduce deaths and limit financial losses. Diagnosis follows a veterinary visit with laboratory confirmation. If you suspect Salmonellosis, contact VetEnt urgently.


Treatment and Prevention

After a veterinary diagnosis has been made, treatment consists of controlling the infection with effective antibiotics or sulpha drugs, and maintaining fluid balance with electrolytes. Salmonella in calves can be prevented or treated with Rotagen containing Salmonella antibodies with fluid replacement therapy. A vaccine is available for prevention, and this should be discussed with your veterinarian.

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