Salmonella growing on a petrie dish

Salmonella is a cause of diarrhoea in calves from 2-12 weeks old. It typically presents with high temperatures, watery/mucoid diarrhoea, possibly blood and flecks of white in the faeces, and a bad smell.

Salmonella is very contagious and can have a high death rate. Calves are infected when they eat salmonella bacteria, which can be present in the environment, feed, or water.

External factors are required to allow infection to take hold – usually lack of colostrum, poor weather or housing, close contact with other infected calves, poor disinfection procedures or bringing in carrier calves. Carrier calves are bought in calves that have met salmonella strains that they have no immunity to and have been stressed during transport. The new strain of salmonella is brought onto your property and because the new calf’s immunity isn’t strong it can take hold and work its way through the shed.

As with most calf diseases getting adequate colostrum into calves is the best prevention. On farms that have had salmonella outbreaks in the past, vaccinating cows pre-calving helps to boost antibodies in colostrum.

Maintaining good hygiene practices in the calf shed will reduce the passing of infection between pens. Things to think about are:

  • Cleaning and disinfecting water troughs
  • Changing or disinfecting boots, changing clothes, and washing hands and arms between areas of healthy calves and sick calves
  • Disinfecting equipment such as feeders used in the sick pen
  • If using gloves discard between sick and healthy calves, avoid stuffing gloves into pockets
  • Feeding younger calves first, do not return to younger calves without thoroughly cleaning boots, changing overalls and washing hands and arms. Feed sick calves last.

Lastly, salmonella can cause diarrhoea in people so be careful of your own health and any children on your farm. Not drinking raw milk while salmonella is on your farm is important as salmonella can be in the milk. Practising the same hygiene practices for yourself is important-leave boots at the shed/away from the house, wash hands thoroughly and be conscious of how you are handling any dirty clothes.