22 December 1995

Muggy housing blamed for high mastitis levels

Mastitis is literally in the air at this time of year. But, as Jessica Buss reports, simple steps to improve ventilation promise to work wonders

POOR ventilation that has left buildings hot and humid in the recent mild weather is to blame for the high incidence of mastitis occurring on some dairy units.

In the worst case reported by ADAS senior consultant David Levick this autumn, 200 litres of milk a day were being discarded from eight or nine cows in a 120-cow herd.

At an average milk price of 26p/litre, this was £52-worth of milk a day thrown away.

Mr Levick claims that a major outbreak is occurring in some herds because hot humid cow housing has allowed the environmental mastitis bug Strep uberis to thrive.

"When you look up in the roof and see cobwebs it guarantees the building has poor ventilation," he says.

"As cows get bigger and more productive, they produce more heat and sweat increasing the stress on their environment."

Mr Levick advises that straw yards are cleaned out more often and that cubicles are bedded and limed more frequently when they are the source of mastitis bugs.

"In the long term consider altering the building to allow more air in," he says. However, he admits that often cow housing is surrounded by other buildings, so is difficult to improve. Slotting the roof will assist air movement above the cow.

"Strep uberis is a difficult bug as it grows in buildings quickly and is also passed around at milking time. It can even grow in teat cup liners between milkings affecting the first cows coming into the parlour at the next milking.

Versatile bug

"The bug is very versatile and also grows in muddy gateways and calving boxes," he adds. Risks are therefore increased when cows walk through muddy gateways – as has been the case with cows grazing late into this autumn to save winter forage stocks.

Strep uberis often causes mastitis in cows within a few days of calving. Mr Levick points out that the amniotic fluid around the unborn calf contains the bug. When her water breaks at calving, she is covered in the bacteria. When she is kept with the calf on infected bedding and suckled frequently, the teats remain open to infection.

Although these cases are usually mild, prompt diagnosis is essential for early treatment. When treatment isnt adequate symptoms will reoccur, warns Mr Levick. Advice on treatment must be sought from the vet.

He says milk samples of infected cows, healthy cows and a bulk sample will show the range of mastitis bacteria about.

The test results will allow the areas where bacteria are predominant to be targeted.