Bovine Ephemeral Fever (BEF) is a viral disease of cattle and buffalo that is spread by mosquitos and biting midges. Usually, affected animals are only sick for a few days, hence its common name – Three Day Sickness.
BEF usually occurs in the summer months between January and April, with the greatest number of cases typically reported in March. Three Day Sickness is known to occur in northern Australia and along the eastern seaboard south to the NSW-VIC border, where periods of heavy summer rainfall are experienced.
The virus causes considerable inflammation and pain in muscles and joints, causing many cattle to go down and may be unable to get up. As a result, access to water, food and shade becomes limited. They may also have trouble swallowing as the virus can paralyse the pharynx, leading to drooling.
Signs of BEF / What to look out for
Diagnosis of Three Day Sickness will require assistance from a veterinarian. Signs include:
- sudden onset of fever as high as 41°C
- shivering
- drooling and nasal discharge
- watery eyes
- animals stop eating and drinking
- lameness and swelling around joints/jaw
- stock may lie down and refuse to move
- sudden and severe drop in milk production
Complications
Deaths are uncommon and generally involve less than 1% of the herd.
The virus can affect the nerves that control swallowing and affected animals are at risk of getting food, water, or saliva into their lungs. This can result in pneumonia.
Heavier cattle that go down are at an increased risk of developing complications. Hence, bulls, heavy bullocks, and pregnant cows are more likely to get worse. While laying down for long periods, nerves and blood flow to the legs can be impacted and, if left untreated, animals may die. A small number of animals that go down may suffer permanent paralysis due to spinal cord damage either as a direct result of the virus, compression while down, or from a fall.
Cows in advanced pregnancy may abort following BEF, due to their high body temperature rather than the virus itself. Bulls, also because of the high fever, commonly suffer temporary infertility lasting from three to six months.
Treatment of BEF
Nursing care is very important for any cattle that cannot get up. To minimise the effects of BEF:
- Get your veterinarian involved. Ask about the suitability of injectable anti-inflammatory medication to decrease fever and muscle inflammation.
- Injections of anti-inflammatory medication or calcium need to be administered early in the course of the illness to make a difference.
- Shade and water are essential to prevent dehydration. Provide a large container of water within easy reach. Ensure the container is stable, full, and has low sides for easy access.
- Provide quality food such as lucerne hay as recovery from illness requires good nutrition.
- If cattle are down, erect a temporary fence to protect their food and water supply from other animals. Otherwise, lifting the animal to a safe and protected spot or shed with soft bedding is useful. Always consider whether lifting and moving is beneficial and practical.
- Lift and roll cattle that have been down, at least one to two times a day to prevent secondary nerve and muscle compression.
- The action of the virus reduces calcium and if cattle cease eating calcium levels can also fall. An injection of calcium can just be what is required to help the animal to get up or stay upright. Have packs of a 4-in-1 calcium supplement available to inject under the skin of down cattle.
- Pour-on or rub-on backline insect treatments to assist in protecting cattle from mosquitos and reduce the viral load that cattle receive.
Prevention of BEF
Prevention of BEF relies largely on vaccination. Many producers will invest in the vaccine for their most productive and valuable stock. This requires some thought as the vaccination program requires two doses. Administer the first dose well before the disease is prevalent in the district. Administer the second dose 4 weeks later (and as close as possible to when BEF enters the area). If left unvaccinated, immunity will develop naturally in your stock over time, with exposure. If in doubt, talk to your vet or get in touch.
References
Be on watch for three day sickness this season | Meat & Livestock Australia
Three day sickness/Bovine Ephemeral Fever | Meat & Livestock Australia
Bovine ephemeral fever: Three Day Sickness | NSW DPI