Better control of Salmonella in sheep

Salmonella can be found in some sheep flocks, possibly contaminating their meat and the farm environment leading to direct and indirect infection of people and animals. It can cause serious illness, including abortion and death, in adult sheep and lambs.

To protect your flock, you should be aware that:

• Any new sheep added to your flock or land could be carrying an infection.
• Vehicles, people and equipment entering your farm may be carrying contamination.

If you suspect salmonella in your flock, you should contact your private vet immediately for advice.  However, prevention is better than cure, and the following steps should be taken to reduce the risk of salmonella to your flock. 

Cows, bulls, calves and pigs may also carry infections more commonly than sheep.

• Keep the flock ‘closed’ where possible.
• Only deal with reputable sources,
• Ask your vet to check the health status of flocks that you may buy from.
• Keep new stock away from the main flock for four weeks.

Salmonella survives well in pooled water, which can be a source of infection or contamination for wildlife, pets or vehicles.

• Place muck heaps and manure stores away from buildings.
• Control run-off to stop it contaminating other pens, feed, bedding stores or vehicles.
• Do not spread manure from other farms on grazing land.
• Leave at least four weeks between spreading manure and grazing or harvesting forage crops.

Movements may spread infection between farms, units or groups.

• Take care when allowing entry to people who have recently worked on other farms
• Provide a clean parking area for vehicles away from animal housing, feed stores and animal waste.
• Clean and disinfect vehicles and equipment that have been on other livestock farms.
• Provide clean hand washing facilities for people visiting the farm. Ideally provide boots and overalls.
• Accept visitors by appointment only.
• On open farms (including Open Farm Sunday) provide adequate hand washing facilities and instructions for visitors, including disinfection of footwear and appropriate use of PPE.

Sick animals usually excrete very large numbers of Salmonella organisms – often billions per day.

• Keep sick animals away from others and take care not to carry infection to other groups on boots, hands or equipment.
• Get a proper diagnosis of the cause of disease quickly so it can be dealt with effectively

Pens and grazing land contaminated by faeces from infected animals can infect the next animals to be placed there. Grazing with or after cattle is the biggest risk, or using cattle housing for lambing.

• Clean and disinfect sheep pens before and after use by other species.
• Pay special attention to cleaning feeders and drinkers/troughs.
• Leave 4-6 weeks between grazing cattle and sheep on the same pasture.

Ineffective disinfection wastes money and in some cases may increase contamination.

• Remove as much organic matter (like mud and faecal contamination) as possible prior to disinfection.
• Use only Government-approved disinfectants at the correct concentration.
• Wash surfaces, allow them to dry then spray with disinfectant to saturation point.
• Allow disinfected surfaces to dry before use.

People can get Salmonella infection from animals or pen surfaces.

• Do not eat or drink in areas where animal faeces are present.
• Wash and dry hands thoroughly before eating and drinking.
• Limit access to animal areas, especially for the elderly, children or immune-compromised people (e.g. after chemotherapy).
• Do not take contaminated boots into the farm house.
• Wash farm overalls in a hot wash immediately after use.
• Ensure that anyone with diarrhoea, stomach cramps or flu-like illness consults their doctor.

‘Straight’ feed ingredients such as soya meal are often contaminated by Salmonella

• Ask to see Salmonella testing records of major suppliers.
• Consider random testing of some consignments and notify suppliers that you will be doing this.
• Store feed in enclosed, dry containment.

If Salmonella occurs on your farm you may wish to discuss vaccination with your vet.

• Vaccination is likely to reduce the chances of clinical cases of main Salmonella types, but may not have much effect on the total length of time that the flock remains infected.
• Good nutrition and parasite control in ewes will provide benefit. To help protect lambs against Salmonella, early colostrum intake is needed to protect the lambs after vaccination of the ewes.

Wild birds and rodents can carry Salmonella and other pathogens between farms. Rodents can be easily infected by Salmonella and amplify it; increasing the risk of spread to farm animals.

• Reduce wildlife problems by keeping feed in vermin proof containers.
• Remove clutter, excess vegetation and perching places around buildings.
• Have an effective rodent control plan.  Regularly check for rats and mice and act at an early stage to stop breeding populations becoming established.
• Bird-proof netting and deterrent programmes can be applied to most situations, e.g. birds are unwilling to fly under netting or through fine threads at entrances to buildings.
• If you have footpaths on the farm, put up signs to remind dog owners to pick up any dog faeces.