Mastitis in ewes is estimated to cost the UK sheep industry £120 million a year. Dawn Prime examines the disease.
Last year’s wet spring and dry summer led to challenging grazing conditions, which could be one of the main reasons why ewe mastitis was more of an issue in 2018.
Emily Gascoigne, a vet with Synergy Farm Health, says mastitis, an inflammation of the mammary gland, poses a significant health and welfare concern.
She explains: “It is a multifactorial disease with more than 30 bacteria types being responsible, but there is one dominant bacteria, called staphylococcus aureus, caused by skin bacteria from the lamb’s mouth or from the environment.
“The first line of defence for the udder against mastitis is the teat end. This has a sphincter closes to protect the teat canal, preventing the entry of bacteria.
“There are cells in the canal of the udder which also play a good defensive role.”
Ms Gascoigne explains that when the lamb is suckling, or during milking, the teat end is open and can stay open for at least two hours.
This means any damaged or injured udders are more vulnerable to bacterial invasion, either due to damaged cells or the teat end not closing correctly.
“The second line of defence a sheep has is the inflammatory response,” she adds.
“This includes cells which help to destroy any invading bacteria.
“However, the inflammatory response does vary depending on the type of bacteria, as some can be harmful and release toxins which can destroy the udder, impair function and cause pain.”
WHAT ARE THE SYMPTOMS OF MASTITIS?
■ Heat and swelling in the udder
■ Pain in the udder which makes the ewe look lame
■ Udder could turn black
■ The milk becomes watery or has a bloody secretion
■ Loss of appetite
■ As the condition is painful, the ewe will not allow her lambs to suckle, resulting in the lambs looking hungry
Chronic mastitis is most commonly found post-weaning with palpable lumps in the udder and culling is recommended.
Some ewes have a sub-clinical infection, so the sheep shows no visible signs. It is estimated that up to half of all ewes are affected by this, however sub-clinical signs are hard to detect, so that amount could be higher.
In all sub-clinical signs, the mammary gland is still infected, with concerning indicators including decreased yield and quality of milk, poor lamb growth and the formation of intro-mammary masses in the udder.
MS Gascoigne says prompt examination is needed if it is suspected a ewe has mastitis.
“You should consult your flock health plan for choice of treatment which should include antibiotics and pain relief as discussed with your sheep vet,” she says.
“It is vital to get prompt treatment for the infection to prevent further damage to the udder function and to minimise the welfare impacts of the disease.
“Culling is recommended because of the risk of reduced milk yield or even coming in with no milk in subsequent years.
“Clear identification at lambing or when the cases are identified is important to ensure animals are not lost in the flock.
“A vaccination is available, and should be given pre-lambing, to reduce the incidence of subclinical mastitis. Speak to your own vet to discuss if this has a role for your flock,” she says.
THERE are factors which you can used on 1000’s of farms do to help reduce the risk:
■ Meeting the ewe’s requirement for energy and protein during pregnancy and while lactating is essential, so they can produce healthy lambs and sufficient milk. Well-fed ewes are in a much better position to fight infection
■ Research has suggested poor body condition (below score three) has been linked to problems with mastitis, as the ewe struggles with milk production. The problem arises where hungry lambs butt the udder and bite at teats to gain more milk, causing udder damage
■ Poor hygiene at lambing will allow environmental bacteria to multiply and increase the chance of mastitis
■ Good udder confirmation is associated with a decrease in the risk of mastitis. In ewes with mastitis or poor udder confirmation, culling should be considered