How to spot the symptoms of Salmonella in calves
- 26 Sep 2022
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Salmonella - Spot it, Stop it!
Salmonella infection can have serious economic consequences on farm, presenting itself in a multitude of different ways and also posing a zoonotic risk to humans.
There are several different groups of Salmonella, only two of which we can vaccinate for (Salmonella Dublin and Salmonella Typhimurium). We often see issues with Salmonella infections in youngstock and taking the time to assess the risks on your own farm can help identify if improvements can be made to reduce the spread of the disease.
How to identify infection in Calves
Salmonella bacteria infect calves via the faecal-oral (muck to mouth) route. Once ingested the bacteria invades the lining of the gut and the enterotoxin causes extreme damage reducing absorption capacity. This can result in scours, septicaemia, dehydration and potentially death.
Other, more unusual, signs can include damage to the tips of the ears when septicaemia causes blood flow to the extremities to be reduced. Any calf suffering from stress or poor immunity is going to be more susceptible to infection.
How do I know if Salmonella is on my farm?
There are a number of different samples that can be taken to work out if Salmonella is a potential risk on your farm. Firstly, any scouring calves should be sampled and faecal culture can reveal if Salmonella is the causative agent. Blood sampling of a group of young stock approximately 3- 6 months of age and testing for antibodies can show if they have been exposed to Salmonella.
Finally, bulk milk antibody is a really useful tool to show if Salmonella is being shed by adults on the farm. Salmonella can be shed in the faeces of asymptomatic cows and so does pose a real risk to calves when these animals pass through the calving yard.
How can you control the risk on your own farm if Salmonella is present?
1. Calving yard management:
- Ensuring that the calving yard is cleaned out regularly (at least every 3 weeks and more frequently if stocked high or with a large number of calvings) will reduce the infection pressure.
- Don’t allow sick cows in the calving pen. These cows are potentially at risk of spreading large numbers of bacteria if they are infected.
- Separate calves and dams as quickly as possible, to reduce the chance of suckling and ingestion of infected faeces.
2. Optimise immunity:
- Ensure all calves receive a volume equalling 10% of body weight of good quality Colostrum as soon as possible after birth. Ideally, this should be in the first couple of hours, as the gut’s capacity for absorbing antibodies reduces quickly after birth.
- If S.Dublin or S.Typhimurium is identified on farm vaccination can provide whole herd immunity. The timing of this may depend on the outbreak and clinical signs seen so is best decided upon with your vet. Ensuring revaccination 3-4 weeks prior to calving will ensure colostrum contains antibodies for Salmonella, which will help improve calf immunity and health
3. Cleanliness is key- The solution to pollution is dilution:
- Ensure all Calf feeding equipment is cleaned thoroughly. You can measure how effective your cleaning protocol is using a luminometer. This machine measures bacterial
- ATP (bacterial energy). This gives a direct indicator as to how much bacteria is on the equipment and how effective your cleaning protocol is. It can be a good starting point to see if any modifications to the cleaning protocol are required.
- Ensure water, feed and any equipment used in the calf housing is kept clean and free from faecal contamination.
- Ensure plenty of fresh clean straw is regularly applied and calf housing is cleaned out with an appropriate disinfectant.
If you are having any challenges with youngstock disease, it is always worth discussing with your vet any diagnostics and potential action you can take. Salmonella can present in many different ways and so knowing what samples take and how best to manage the risks on your own farm should reduce the impact of the disease.
