1 March 2002

Stress and pasturella

EWE stress due to recent changeable weather has been blamed for pasturella reappearing in some flocks and increasing lamb losses.

Surrey vet Rob Drysdale has recently seen a number of acute pasturella cases. "It is a stress-related disease, any reduction in immune function and the bacteria will take advantage.

"Recent weather with cold and mild spells has stressed many ewes. In addition, good grazing last autumn meant some ewes were left out longer and moved later than normal."

Another reason for the cases is that some ewes have not received their annual pasturella booster vaccination. One flock had abandoned routine pasturella vaccinations to reduce costs, he says.

"This can be tempting as pasturella may not appear for 2-3 years after stopping vaccination. All it takes is stress from bad weather or being chased by dogs and lamb losses rise sharply."

Mr Drysdale believes it is not too late to act. "Consult your vet and devise an action plan. Ideally, ewes should be vaccinated 3-4 weeks before lambing as it protects them during this stressful period and lambs gain protection from antibodies in colostrum." &#42

Pasturella can also cause mastitis – black bag – with the risk of ewes losing a whole quarter or death in severe cases. To combat this, many clients now include antibiotics for mastitis in their lambing kits, adds Mr Drysdale.