Lambs at high risk of pasteurellosis

With autumn around the corner, AHDB Beef & Lamb and Farm Post Mortems Ltd are warning producers of the risk of pasteurellosis (pneumonia) in lambs.

Pasteurellosis is an opportunistic disease, caused by bacteria Mannheimia haemolytica or Bibersteinia trehalosi. It is often triggered by stress which can be caused by management tasks (eg gathering, handling or shearing), transportation, change in diet, worms and other diseases. Managing the flock to reduce stress is important in prevention and conol of pasteurellosis. Climate can also be a factor and the change in weather as we move into autumn means cases usually peak at this time of year. Losses can be high and may occur suddenly, with lambs found dead or almost dead.

Now is a good time to check whether lambs are prepared for a disease challenge. Vaccination is an effective way of reducing the risk, but lambs’ immunity is not stimulated until they have had two doses of a combined pasteurella and clostridial vaccine. It is important that the vaccine is given at the right dose and at the right time. Work carried out by Farm Post Mortem Ltd found around 25 per cent of the lambs that died due to pasteurella had not received the vaccine in accordance with the data sheet, eg received only one dose or the interval from the previous dose was more than three months.

The vaccination programme should be planned so lambs have completed the course two to three weeks before the risk period (late summer/early autumn). Even if lambs have received two doses earlier in the year, a booster dose may be necessary in some circumstances prior to periods of high risk, so store lambs may need a third injection before autumn to ensure they have sufficient pasteurella cover.  

It may be worth asking your vet to take blood samples from the lambs to check their trace element and Border Disease status. The risk of lambs dying from pasteurella will be higher with poor trace element status and a positive result for Border Disease. Farm Post Mortem Ltd found around 20 per cent of the lambs that died due to pasteurella had received the vaccine correctly but had other issues, such as Border Disease, that may have affected how well the vaccine worked.

Pasteurellosis can be treated with antibiotics in the event of an outbreak, but prevention is better than cure and using vaccinations to prevent the disease will reduce losses and help lower the use of antimicrobials within the flock.

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About The Author

Deputy editor of Agronomist and Arable Farmer as well as responsibility for the Agronomist and Arable Farmer and Farm Business websites. After 17 years milking cows on the family farm John started writing about agriculture in 1998 and has since written for a variety of publications and has developed a wide circle of contacts within the industry. When not working John is a season ticket holder at Stoke City and also of late has become a fitness freak, listing cycling, swimming and walking as his exercises of choice.