Challenge to control ewe mastitis

Mastitis, more usually a problem of the dairy sector, is testing the patience of many shepherds this spring, as increasing numbers of ewes experience the condition.

But there are few if any guiding principles to follow in its management, making prevention and treatment difficult to achieve.

Independent vet consultant Tony Andrews says there can be a number of causes of mastitis in sheep, including pasteurella, environmental causes, such as E Coli, and contagious causes, such as the staphylococcus bacteria.

“Where mastitis is seen early in lactation it is often due to the involvement of pasteurella.

This can either come from ewes themselves or lambs may pass it to ewes when suckling.

“Vaccination against pasteurella may be beneficial, but its efficacy in preventing mastitis is difficult to quantify.

However, anything which reduces the level of infection in the environment has to be beneficial,” he explains.

When it is being caused by one of the staph bacteria Dr Andrews says hygiene in and around the lambing shed is of paramount importance.

“Group yards housing ewes before lambing should be bedded regularly to ensure ewes udders are kept as clean as possible.

“And once ewes have lambed and move to individual pens these should also be kept as clean as possible.”

Dr Andrews recommends cleaning out pens between each ewe and using a suitable disinfectant before restocking them.

“The simple act of cleaning out individual pens will remove most of the organisms responsible, so this must be done as often as possible.”

When there is insufficient time or labour available for pens to be cleaned out between every ewe Dr Andrews suggests using a disinfectant and bedding pens with a deep layer of straw.

But Shropshire-based shepherd Nick Davies reckons despite rigourous cleaning and disinfection of individual pens between ewes he still sees about 30 cases of mastitis in ewes every year.

“With 3000 ewes on the farm that means we’re seeing mastitis in 1% of ewes, meaning we have more ewes with mastitis than we do barren ewes.”

Historically, Mr Davies has tried a variety of methods, including using mastitis tubes intended for treating dairy cows.

“We now use a targeted antibiotic treatment which treats cases rapidly, reducing the number of ewes unable to rear their lambs due to mastitis.”

However, SAC sheep specialist John Vipond believes much of the problem comes from previous years.

“Organisms tend to enter teats at weaning and hold over until the following year when they cause infection during lactation.”

To prevent this Mr Vipond suggests feed blocks and salt licks shouldn’t be placed out for ewes in late lactation.

“The danger of these blocks is that lambs can lick them and pick up bugs from other lambs.

Once they return to their dams and suckle they can pass infection to the teat and hence the udder.”

Where farmers believe the problem is being caused by infection being picked up in the lambing shed Mr Vipond believes using pine woodshavings instead of straw in lambing pens may be beneficial.

“This can reduce the bacterial challenge in lambing pens and hence may reduce mastitis incidence.

“Additionally, shearing ewes’ bellies before lambing can reduce the amount of dirt and debris carried around by ewes, so reducing the chances of bugs being picked up and transferred to the udder.”

This year Mr Davies intends to manage mastitic ewes as a separate group to aid both treatment and prevention of further cases.

“Splitting problem ewes out from the main flock means there should be a reduced chance of infection spreading to other ewes from either cross suckling or contamination by salt licks.”

For the long-term Mr Vipond suggests it may be a breeding challenge for farmers to address.

“Ewes with big teats or low udders can be particularly prone to mastitis, so retaining replacements from these ewes should be avoided.”

On this front Mr Davies believes hard culling is the only way of limiting the number of problem ewes.

“But with most farmers buying in replacements it is difficult to select against poor udders,” he adds.