Redwater infection in cattle is a disease that many farmers are aware of and that livestock are particularly susceptible to when on under-grazed rough pastures.
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.
Animal Health Ireland’s (AHI’s) Beef HealthCheck programme manager Natascha Meunier offered advice to livestock farmers in the company’s August newsletter on identifying the disease, preventing and treating the disease.
Signs and symptoms of redwater
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.
Keeping pastures well managed can help prevent the disease, although margins near hedges may still be a suitable environment for these ticks.
Recent studies have shown the disease is declining in Ireland and with fewer cases, farmers may be less familiar with the clinical signs.
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:
- 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.
Animals can die quickly following the first appearance of symptoms.
When an animal has redwater, an early diagnosis and timely veterinary treatment are key to survival.
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.
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.