First call this morning was to a two-year-old heifer who was off-form and slightly nervous. Like most calls, before you get on farm you start thinking about potential diagnoses that might fit the clinical picture.

Things like meningitis were running through my head. On arrival to the farm, however, another vital piece of information was given to me: “She was bought in recently.”

Again, this can change your train of thought in relation to disease. This was especially true in this case given that I was on a suckler farm that grazes a lot of hilly ground. Before we got to the crush, I was asked: “Could it be redwater?”

I might often run through clinical diagnoses in my head before I arrive on farm, but I have learned never to presume anything until I do a full clinical exam. I was presented with a Limousin heifer that had lost a lot of condition rapidly and had a sweat up.

She was difficult to examine but finally we discovered she had a high temperature, diarrhoea and an extremely fast heart rate. Moreover, her urine was a dark red port colour. All these clinical signs confirmed the suspicion of a disease called babesiosis, or redwater.

The cause and treatment of redwater

Redwater or babesiosis is caused by a blood parasite that attaches to and destroys red blood cells. This parasite is carried by ticks. When the infected tick feeds, it is transferred into the animal’s blood system. Thankfully, this heifer’s blood volume was not yet massively affected, meaning that treatment should resolve the situation. However, depending on the stage the animal is presented at, this can vary widely.

We often have to give these animals blood transfusions as well as other treatments. As the condition progresses, these animals can present with constipation and weakness due to the anaemia. If you suspect redwater, minimal stress should be caused and great care taken, as these animals tend to be nervous, possibly due to low blood oxygen in the brain.

Life cycle

Ticks have a three-year life cycle. If they feed on cattle at any stage throughout this cycle, the disease can be transmitted. There are certain types of ground where ticks will survive better, such as marginal hill ground or rougher grazing ground. In well-managed pastures we see fewer ticks, but they can still be present.

Ticks prefer mild wet conditions and do not like excessively dry, hot weather, so conditions at the moment are perfect for tick-related diseases. Where we see problems is when older animals from tick-free ground are introduced to tick areas. Younger animals on farm will have a good degree of resistance. Interestingly, we have seen an increase in tick activity and subsequent diseases associated with ticks such as TBF (tick-borne fever).

It will be two to three weeks before the parasite is introduced into blood stream and you see clinical signs. So, observation of newly purchased cattle or new grazing ground is often the best way of spotting the disease. Cattle that are isolated from the group that are slow to rise and hollow in the rumen should always get further attention and observation. There is a treatment available for your vet to give – imizol (imidiocarb dipropionate). There is a 213-day meat withdrawal on this product and 21-day milk withdrawal.

Control and prevention

Controlling and preventing disease can be done in a number of ways.

Imizol can be used as a preventative dose by using twice the dose of a treatment dose. It is important to talk to your own vet about using this product. It requires infected ticks to be active at the time and will only give four weeks’ cover, allowing the animal to develop a natural immunity.

Pasture management is important to inhibit ticks. It is crucial to prevent favourable conditions for ticks to prosper. However, the laws in relation to burning hill ground have made these controls difficult for a lot of hill farmers.

It is important, especially when buying in stock over six months old from areas with no tick prevention techniques, that careful monitoring is used. There are also some pour-on solutions available which reduce the risk of ticks, but they are only part of a control plan.