Salmonellosis (Calf paratyphoid)
Common names: Calf paratyphoid
Description: Bacterial infection
Salmonellosis, also called calf paratyphoid, is a bacterial infection which affects all animals including cattle, birds, pigs, sheep and humans. It is more serious in young calves and weaned calves and can cause a wide range of symptoms.
There are more than 1000 types of salmonella. In young suckling calves, the disease is caused by a type of Salmonella called Salmonella typhimurium. In weaned calves, the most common cause of the disease is Salmonella Dublin. In adult animals Salmonella can cause abortion (see more here).
Salmonella are excreted into the environment by healthy symptomless carriers, which is either the dam or other calves. The calf becomes infected through ingestion of the salmonella from the environment (especially contaminated pastures and feeds, housing, and contaminated stagnant waters). Salmonellosis is common in unhygienic, dirty and wet environments and when calves are mixed at weaning.
A Salmonella infected herd may remain infected with Salmonella for several years with disease appearing now and then in calves but not in older animals.
Signs of Salmonellosis
In young calves when the disease is caused by S.typhimurium, the characteristic symptoms include the following:
- In the most severe form, there is profuse diarrhoea with a very bad smell accompanied by high temperature. Salmonella invade the whole body very fast – this is called septicaemia. Death may occur within 24 hours or less, before the diarrhoea becomes visible!
- In chronic form, the affected calf would have pasty dung, and is often unthrifty. Some calves can carry the disease for a long time without showing clear disease signs. Such calves shed a lot of salmonella in their faeces when they become stressed (e.g. cold and wet weather) thus infecting other calves
In weaned calves, affected with S. dublin, symptoms include:
- scouring which resemble the one caused by S. typhimurium may occur.
- Signs can vary a lot and include septicaemia, pneumonia, meningitis and also kidney infections.
- Sometimes, scouring may be seen containing lumps of intestinal wall, blood and mucus. Infected calves would be dull, lack appetite and may also be coughing
- Occasionally, a group of calves may appear thrifty abruptly and sudden deaths may be observed.
Prevention and Control
- Isolate the sick calves to reduce the likelihood of infection to the remainder of the group.
- Ensure clean housing, move animals out of dirty Bomas to avoid calves being exposed to faeces full of salmonella.
- Avoid wet and damp conditions. Salmonella thrive in the environment when it is wet.
- Vaccination using a live vaccine is a good control measure and this can be given from day old or soon after purchase of the calf, (but at the time the vaccine is only available in Botswana/South Africa).
- Give adequate colostrums (as soon as possible and as much as possible) to boost immunity of the calf soon after birth.
- Avoid purchasing replacement calves which may carry salmonella into your herd, instead it is advisable to rear your own replacement calves.
It is advisable to treat the animals as soon as possible with antibiotics. The drugs can be administered through the mouth or by injection. But response to treatment is often very poor, especially with septicaemic salmonellosis because it kills fast (and can kill 75% of the animals if they are not treated).