There have been a number of reports in the wider Dungog district of suspected cases of Bovine Ephemeral Fever (BEF), also known as 'three day sickness'.
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The illness is currently circulating in mosquitos and is affecting cattle in the Hunter Local Land Services area.
The virus was confirmed on the Mid Coast in late March and cases in the Hunter are expected over the next few months.
Hunter Local Land Services is encouraging all cattle producers to step up monitoring of their herd to identify affected cattle and be prepared to treat and nurse animals.
District Vet Dr Lyndell Stone said while three day sickness is relatively common on the coast, frequently occurring in late summer or autumn, we have had very little virus transmission during the previous two-three years of drought.
"Producers should be prepared that any cattle born on or introduced to the coast particularly after 2017 (last period of BEF transmission) could be affected by three day sickness until mosquitos disappear with cold weather," said Dr Stone.
"Cattle older than about four years, that were born on the coast, most likely have been infected before and probably have good immunity.
"Daily monitoring of your herd is particularly important during this time, to ensure you identify any affected cattle and provide timely and suitable treatment and/or nursing care - for the most part, BEF is a mild transient illness hence the name 'three day sickness'."
BEF causes a short but significant fever, drooling, shivering, a discharge from eyes and nose, lameness and muscular soreness. Many animals become recumbent for a few days with heavy animals such as bulls and big cows most severely affected. A transient infertility in bulls can occur and a small proportion of pregnant cows can abort, presumably from the high fever.
"Early veterinary treatment can mediate these impacts and prevent animals from becoming recumbent," said Dr Stone.
"Good nursing care can be the difference between affected cattle recovering in the normal three-day window or succumbing to secondary health effects from dehydration, particularly in hot weather, or sustained recumbency."
The Hunter Local Land Services District Vet team has the following advice, to assist your on-farm management plan.
Monitoring Cases on Farm
Inspect cattle daily particularly if three-four years of age or younger or have been introduced to the region after the summer of 2017.
Seek advice from your private vet if you are unsure if your cattle are suffering from three day sickness or another illness mimicking the signs of three day sickness
Diagnosis is either on clinical signs or blood test. However, BEF can be difficult to confirm via blood test as cattle clear the virus very quickly.
Blood needs to be sampled as soon as the animal looks sick to get a positive result (i.e. within the first 24-36 hours of illness). Veterinarians are skilled at identifying the clinical signs of BEF and diagnosing on this basis. In a few situations however it may be useful to test animals to obtain a diagnosis if clinical signs are inconsistent.
Managing cases on the farm
Nursing care is very important for any cattle that are down or relatively immobile.
The virus causes considerable inflammation and pain in muscles and joints and cattle may become recumbent or stop moving. This can prevent access to water, food and shade. They may also have trouble swallowing as the virus can paralyse the pharynx hence they often dribble saliva. To mediate the effects of the disease please;
- Shade affected animals from the hot sun
- Provide a large tub of cool fresh water within easy reach of immobile cattle. Make sure the tub is stable and can't be easily knocked over and is full at all times. Shade and water are both essential to prevent dehydration.
- Provide good quality food such as lucerne hay as recovery from illness requires good nutrition.
- If cattle are immobile in a paddock you may have to erect a temporary fence to protect their food and water supply from the unsympathetic access of their paddocks mates. Otherwise lifting the animal to a safe and protected spot or shed with soft bedding is worthwhile.
- Lift and roll recumbent cattle at least one-two times a day to prevent secondary nerve and muscle compression, if they have been down for more than a day or so.
Dairy Australia has excellent resources on nursing down cattle available at https://www.dairyaustralia.com.au/farm/animal-management/animal-welfare/cow-welfare
Speak to your private vet about the suitability of injectable anti-inflammatory medication to mediate fever and muscle inflammation.
In addition, having a couple of flopaks of a 4in1 calcium supplement (available from your vet or produce store) on hand for injection under the skin of down cattle can help with muscle function.
The action of the virus depletes calcium from the animal and if cattle cease eating calcium levels can also fall. An injection of calcium can just be the added help they need to get up or stay up right.
These steps may be warranted particularly in larger and valuable cattle, bulls and pregnant cows.
Insect protection (pour-on or rub on backline treatments) might also be of assistance in protecting cattle from being bitten by mosquitos and reducing the viral load that cattle receive.
In a very small percentage (1%) of infected cattle the virus lodges in the nervous system and these animals might never regain the ability to stand or walk. Thus seek veterinary advice for animals that remain recumbent after five-seven days despite good nursing care as outlined above.
Mosquitos carrying the virus have also made their way to some inland areas of NSW that haven't had virus distribution for more than 10 years. Thus many areas of the state are experiencing issues with BEF.
The NSW DPI fact sheet on BEF is available at https://www.dpi.nsw.gov.au/animals-and-livestock/beef-cattle/health-and-disease/viral-diseases/bovine-ephemeral-fever
