Farmers are being reminded to be vigilant as a spike in the number of redwater infections has been reported in cattle herds in some regions of the country.
Traditionally, June and September are two times of the year when the risk of a redwater outbreak is most prevalent.
The hot weather this summer has been suggested as a potential contributing cause to the spike in cases this year.
Cattle are most at risk when on under-grazed rough pastures with heavy grass covers that were not grazed in the later part of last year.
Farmers who leased ground this year with heavy grass covers that may not have been grazed last year should also be vigilant as cattle grazing these pastures are particularly susceptible to redwater infection.
Redwater
The name of the disease comes from one of the most tell-tale symptoms of an infected animal: Frothy urine with a red-brownish colour.
Redwater is caused by the parasite Babesia divergens and is transmitted by a tick that is found in Ireland, particularly in the west and along the Shannon river system.
According to Animal Health Ireland (AHI), keeping pastures well managed can help prevent the disease, although margins near hedges may still be a suitable environment for these ticks.
In recent years, the disease has become less prevalent, but farmers should still be aware of the signs and symptoms of redwater infection in cattle.
After an animal is bitten by a redwater-infected tick, it can take up to three weeks for any signs of disease to show, according to AHI.
Early stage signs of redwater infection:
- Animals staying away from the group;
- Reduced appetite;
- High temperature;
- Frothy urine with a red-brownish colour (giveaway symptom);
- Diarrhoea (often ‘pipe-stem diarrhoea’ passed as a thin jet).
- Later-stage signs:
- Weakness/staggering, animal unable to stand;
- Changes in colour of gums and under eyelids to very pale (anaemic) or yellow (jaundice);
- Constipation;
- Death.
Animals on pasture should be monitored for signs of disease, particularly during spring or autumn and especially if they have been recently introduced to the herd.
When an animal has redwater, early diagnosis and timely veterinary treatment are key to survival. Animals can die quickly following the first appearance of symptoms.
According to AHI, treatment may include an injection of imidocarb dipropionate to kill the parasite, however this drug has a withdrawal period of 213 days for meat and 21 days for milk. Veterinary advice should be sought immediately if cattle are showing symptoms.
Prevention
There are a number of management practices that can help to reduce the risk of redwater cases in a herd.
Dense vegetation and under-grazed rough pasture are, as previously mentioned, favorable areas for infection-carrying ticks, so reducing livestock access to these areas can help avoid cases of redwater.
The most susceptible types of cattle to redwater include thin animals, cattle that have suffered a setback, pregnant cows, and animals without previous exposure to redwater parasites.
These cattle should be kept out of tick-infested areas, in particular during high-risk periods which are from April-May and August-October. Mild, wet weather can allow tick activity to continue through the summer.
Calves show natural resistance to redwater and tend to not develop clinical disease under six-months-old, according to AHI.
Calves over six to nine-months-old that have not been exposed to redwater ticks and are introduced to tick-infested areas are highly susceptible to infection and serious illness.
Specific preventative measures such as topical tick treatments or preventive drug treatment can be used to prevent redwater.
Concerned farmers should speak to their veterinary practitioner on the best approach from their herd.