Salmonella Dublin Infection in Cattle

Diseases caused by Salmonella bacterial infection cause high death rates in cattle. All salmonellae found in cattle can potentially spread to humans.

Cause

The source of the infection is usually feces from infected cows. Sub clinically affected cows can shed as many organisms in their manure as the cows that are sick with salmonellosis. Other sources of infection may be rodents, birds, flies, feral cats, dogs, and, rarely, people. Salmonella outbreaks commonly last several months. It is also very seasonal with most cases occurring around October.

Symptoms

• Fever
• 
• Lethargy
• Drop in milk production
• Bloody and often watery diarrhoea and mucus
• Death occurs in around 75 per cent of affected animals if they are not treated.

The sub acute form varies from a milder form of the acute disease to infection without obvious disease. Abortion can occur in severely ill animals, but more often it occurs in a cow with no other signs of disease. Abortion due to Salmonella dublin is the most commonly diagnosed cause of abortion in UK laboratories. In calves, Salmonella dublin is usually seen around two to six weeks old.

 

Treatment

Antibiotics and supportive treatment, particularly fluids either orally or in the vein, increase survival rates in calves and adults. Salmonella dublin is usually sensitive to most antibiotics.

An additional problem with treating adults is that some, but not all, treated animals will become carriers, that is excrete Salmonella dublin in their faeces for prolonged periods without ever showing signs of disease. When treating S. dublin get advice from your vet on which animals to treat and what to treat them with.

Prevention

Infected animals must be separated and isolated away from the rest of the animals in the herd.

Ensure to have proper barrier nursing and handle, feed and treat ill animals after feeding and handling others.

Ensure that isolation is effective – too many farms have isolation facilities that are near calving boxes. This is a highly effective means of spread of disease as calving cows are at their peak risk of infection.

Milk from ill cows should not feed to calves. Milk is a very good source of bacteria and disease is very common in calves fed infected milk. Hygiene is essential..

Vaccines are available, however once Salmonella dublin has entered a herd, vaccination alone will not control the spread of infection. Good husbandry and hygiene is essential if control is to be achieved.