Nov2013_News from UQ Vets Dayboro
Welcome to part two of our coverage on bovine vaccinations and diseases.
This time we will write about a viral disease of cattle, known as Bovine Ephemeral Fever (BEF), also known as ‘Three Day Sickness’.
What is BEF or Three Day?
BEF is a virus transmitted by biting insects. Biting midges and Mosquitoes are the usual culprits.
This disease is predominant in Coastal SE Queensland and Coastal Northern NSW; with a seasonal pattern seen from December through to April each year.
BEF poses a real threat of economic loss, as it is often the more valuable stock which are most affected i.e. lactating cows, pregnant cows, bulls and heavy (fat), well-conditioned animals.
Clinical signs and effect of disease:
Affected cattle display symptoms of fever (which can wax and wane), sudden drop in milk yield, abortion, loss of appetite, depression, (shifting) lameness, swollen joints, salivating, excess nasal discharge, watery eyes, and recumbency. Many animals can get sick but, with good nursing care, few die.
Clinical signs often have a sudden onset, generally lasting three days (hence the name ‘Three Day Sickness’); however in some animals it can seem more like ‘Three week sickness’!
Age seems to affect the severity of the disease with stock under 12 months of age demonstrating milder clinical signs.
In our lactating dairy cattle, the effects can be dramatic – both to the animal and the producer! Lactating cattle will often have a drop in milk production by 50% and commonly more. Some papers report that these affected animals will have more than a 15% drop in milk yield following their recovery. Cattle in late lactation will often dry off. Farmers can expect an increased occurrence of mastitis and an elevated somatic cell count.
In our beef cattle, the disease shows the most dramatic effects in heavier stock and in bulls. That is, the ‘best’ animals often seem worst affected. Heavy animals tend to lose significant condition and may not fully return to their previous condition. The fertility of bulls can be affected due to the fever, rendering them temporarily infertile. This could mean that some bulls would not be able to be used for an entire season as infertility can last for up to six months. There are reports of BEF causing permanent infertility.
High fever can cause abortion.
Deaths are usually due to problems caused by cattle being down for many days.
Diagnosing BEF:
Diagnosing BEF is usually made based on the animal’s clinical signs. Tests can be performed through the DPI, by comparing the animal’s antibodies at the onset of clinical signs and again a few weeks later.
Treatment:
Some animals do not require treatment (despite their lameness, some animals are unable to be caught and restrained for assessment!). High producing cattle (dairy cows and bulls) should receive treatment to improve their outcome and productivity and for their welfare!
Downer animals should be provided with shade at all times and easy access to water and feed. It is important to remember that cattle can drink up to 50L per day. If these animals are not eating or drinking then veterinary attention is important so as to rehydrate the animal and provide pain relief and anti-inflammatory medication (they are likely to have painful, swollen joints). Cattle should be turned regularly so as to improve blood flow and reduce muscle damage caused by poor circulation and weight from the animals body. Due to the animals’ weakness and difficulty/inability to get up it is recommended to move them off steep hills where they are at risk of rolling or sliding down, (possibly into a dam).
Prevention and Immunity:
Initiating a vaccination program can result in long term immunity and minimise the effects that BEF has in the herd.
The live vaccine is a prescription medication, which is given under the skin followed by another injection four to six weeks later to provide the animal with 12 months cover. The vaccine is repeated annually.
Following vaccination (boosters) the animal should have immunity four weeks later.
Animals can be vaccinated from five months of age.
It is recommended that the vaccine be given prior to the commencement of the BEF season (i.e. September to November); and that the annual vaccination ideally be administered at least 10 weeks prior to the start of the season. However, the vaccine can be administered at any time of the year.
Unvaccinated cattle infected naturally with BEF will have long immunity; however it is not lifelong and varies from case to case. Therefore, for those animals which become infected, it is recommended they receive their annual booster commencing the following season.
When introducing new stock, it is recommended to commence their BEF vaccines early, or vaccinate them a month prior to arrival on the new property.
Further information:
Further information on Bovine Ephemeral Fever can be found on our website www.dayborovet.com.au and on the Queensland and New South Wales DPI websites.
PS…
A big thank you to the Dayboro Joey Scouts…Dr Scrivens had a fantastic afternoon on Thursday (October 17th) spending time with you at the clinic. J
UQ Vets Dayboro,
125 McKenzie Street, Dayboro.
Phone 3425 1544 ALL HOURS
