Three day sickness

March 2020

Three Day Sickness, otherwise known as Bovine Ephemeral Fever or BEF has been diagnosed in cattle right across the Central West region. It started in the north around Coonamble in late February and has now been reported as far south as Forbes. It may remain active in the region for the next couple of months, so producers are encouraged to be on the lookout for clinical signs in their herds.

About the condition

BEF is a viral disease that causes high fevers that last a few days, hence the common name of the disease, Three Day Sickness. The disease is spread by mosquitos which have been blown from Queensland with the easterly and northerly winds that our part of the world has experienced lately. The warm wet conditions and local mosquito populations have amplified the disease.

BEF is also known as the “one in eight year disease”, meaning that it sweeps through an area roughly every eight years or so. We have not seen BEF since the wet summer of 2010-2011 so we are overdue for an outbreak, and it is thought that most of our animals will be immune-naïve and susceptible to this wave of disease. Once they’ve had it, they should get good immunity and not become re-infected in their lifetime.

Symptoms and impact

Animals affected by BEF get stiff, lame, may lay down and refuse to move. Some animals may have a marked drop in milk production, or may abort calves. Heavily conditioned animals such as bulls and big cows are most severely affected, and we have had reports of some deaths, although this is not common. While the vast majority of animals recover after a few days, the disease can cause quite marked loss of condition and economic loss.


BEF can become an issue for long term production when bulls become infected. The prolonged fever affects sperm production and quality, which can cause transient infertility lasting 3-6 months. For this reason, it is recommended that bulls are prioritised for vaccination, are treated early in the course of the disease, and be semen tested 3-6 months post infection or prior to their next joining by an Australian Cattle Veterinarian.


As mentioned, prevention is possible using an available vaccine, although there are a few things to consider before using it. Primarily, it is now too late to vaccinate for most herds; but also the vaccine is costly (between $15-20/dose) and there are issues with supply at the moment. Talk to your local district veterinarian, or private veterinarian about vaccination, especially if you have high value animals such as bulls and heavily conditioned cows, and you are one of the lucky ones who hasn’t been hit by BEF yet.


If you find you have animals affected by BEF, they can be treated using anti-inflammatory drugs, also available from your private veterinarian. A 4-in -1 flowpack given under the skin can also help the animal recover. Treatment is best given early on, preferably before the animals lie down, so please be on the lookout for disease and act early. Nursing care is also important such as provision of food and water to down animals, and rolling cattle to avoid pressure sores and muscle damage to their limbs.

If you see any illness in your livestock, please contact your nearest District Veterinarian.

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