Contagious mastitis is on the increase – and all too often infection is spread because it’s assumed water temperature used in line-washing is “hot” when in fact it’s far from reaching the required temperature needed for effective cleaning.


And when seemingly correct steps are taken to milk infected cows at the end of the milking session, ineffective washing of the line will simply allow infection to spread.

Talking to Lancashire dairy farmers at a contagious mastitis event organised by Livestock North West, Ian Ohnstad of the Dairy Group said strict parlour hygiene was essential to combat the spread of infection, along with precise monitoring of the water temperature used in the line-wash.

“Hot water can vary by 20C on individual units depending on who is washing the plant – and this is a concern,” he said.

Looking at the role of the milking machine in the spread of contagious mastitis, Mr Ohnstad said it was important to treat infected cows immediately, but equally to prevent the spread of infection.

“Old and soiled milking liners, poorly sanitised equipment and poor operator technique are the three keys areas of most associated with the spread of contagious mastitis.

“Hygiene is king and yet it still needs attention on many farms, especially as we see herds getting bigger and run with less labour. The lack of attention to detail that can cause contagious mastitis is not necessarily through negligence but often because staff are simply under too much pressure.”

And in order to ease pressure on staff thus allowing more time for fundamental health issues, Mr Ohnstad recommended using automatic back-flushing systems.

He also recommended milking high cell-count cows last and urged farmers to be “obsessive” about their standards of milking equipment cleaning. “Never assume anything; always check temperatures, flow rates and levels of chemical being used and ensure that air-injectors are working properly.”

Vet Jude Roberts, Leonard, Lambert and May also urged farmers not to be complacent about “the odd case of contagious mastitis”.

“When something has gone wrong in the parlour and it triggers a case of contagious mastitis it’s essential to find the root cause of the problem – as well as making sure the infection doesn’t spread to other cows.”

And one of the best preventative measures for dealing with contagious mastitis was to be constantly aware of any “noise changes” coming from the milking equipment in the parlour.

“Working in the parlour for several hours a day means the sounds of the system are regular throughout milking time – you get tuned-in to the regular noises when everything is working properly. But when there is any change in the pattern of noise coming from any part of the system it should be checked out immediately.

“The fault signified by a noise change probably means the pressure has altered and that causes cows not to be milked properly.

“Cows that look uncomfortable, clusters dropping off and cows still leaking milk can mean the vacuum isn’t working and when that’s the case it must be investigated immediately,” she said.

Ms Roberts also said carriers of infectious pathogens were not always identified early enough. “These animals often come from the high-yielding group, but other cows in the mid-range of cell counts are nevertheless potential carriers of infection. These cows should not be overlooked and should be treated as though being a confirmed mastitis case.”