A Mayo vet is linking increased number of redwater cases in cattle to rising deer numbers in the county.

Paul Cummins, a vet based in Ballinrobe, Co Mayo, said that ticks are taking over in parts of the county as deer numbers increase.

“Nothing kills them. The deer population has gone up drastically around Lough Mask, Partry, Clonbur, Ballinrobe and Ballyglass. As they spread, we’re seeing more cases of redwater,” he told the Irish Farmers Journal.

Redwater is transmitted to cattle by ticks, which he believes are being carried by the deer. Redwater causes fever, anorexia, diarrhoea, weight loss and red discolouration of urine before cattle go down.

Cummins said that immunity is an issue in cattle too. “What’s happening is that with contracting cattle numbers, we’re not getting as many cattle grazing on rougher ground, so there are less cases of redwater.

“If you introduce cattle to that ground you will have redwater. They have no immunity built up on it. My theory on immunity is that it is age-related. You’ll rarely see an animal under one year with redwater. The first year of contact with ticks is where the immunity comes from,” the vet said.