Milk producers are warned to be on the lookout for a new syndrome where single quarters dry up during lactation without any signs of mastitis or abnormal cell count.

It’s an expensive condition, says Gloucestershire-based vet Roger Blowey, of Wood Vet Group.

“Although the other three quarters partly compensate, there are still yield losses of up to 15%, plus there is the hassle of milking a three-quartered cow,” he explains.

He describes the syndrome as slow in onset, with the animal slightly light in one quarter.

“There is no swelling, clots or pain associated with mastitis and no consistent increase in somatic cell count.

The lightness progresses and eventually the quarter dries up over 1-2 months.”

Mr Blowey would like to hear from others with experience of similar cases, but believes the syndrome could easily missed in a busy parlour, only noticed when the quarter is almost dry.

“Report it to your vet.

As it is a new condition, you could get initial investigations free of charge.”

Three herds so far have reported cases, most in first lactation heifers.

One 300-cow herd had 13 cases of which seven were in first calvers; a second 240-cow herd saw six out of eight cases in first calvers.

Cell counts were low ranging from 17,000 to 58,000 cells/ml and cells were monocytes, rather than neutrophils which would be expected in the early stages of bacterial infection, he explains.

This suggests a chronic long term problem.

Extensive bacteriology has shown nothing significant, blood tests for mycoplasma have proved negative and Mr Blowey has found no obvious milking machine fault or genetic link.

He wonders whether the condition is an unusual response to a bacterial infection such as E coli.

Jay Greenwood, whose 240-cow herd has experienced this syndrome, points out that a disproportionate number of his affected cows also failed to get back in-calf.

He says those cows which did calve again milked normally, but then half of them dried up in the same quarter.

Mr Greenwood estimates yields for affected cows in his 10,000kg herd have dropped by 5-10%.

fwlivestock@rbi.co.uk