Producers should be on the lookout for Akabane in their calving herds this season, with an increased potential risk of losing both cows as well as calves.
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Producers should monitor calving herds for Akabane virus affected calves following detection of positive results in sentinel herds and the investigation of reported cases of increased late term abortions and affected calves.
“Routine blood samples are collected from sentinel herds in NSW as part of the National Arbovirus Monitoring Program. Samples collected from both NAMP herds and affected calves at both Glen Innes and Tenterfield have returned positive antibodies to Akabane virus,” Northern Tablelands LLS District Vet Dr Lisa Martin said.
Akabane is a virus that is carried by biting midges that generally spread on winds from the north and east of the country. Akabane can cause deformities in calves or late term abortions if a cow or heifer that has not previously been exposed to the Akabane virus, comes in contact with the virus during pregnancy.
The effects of the virus within a herd largely depends on the immune status of the breeder females and the stage of pregnancy at exposure. Cows or heifers that are immune to the virus from previous exposure do not have any pregnancy or fetal problems.
Infection with Akabane virus late in pregnancy can cause cows to abort, with a higher percentage of pregnancy tested in calf cows failing to produce a calf. Late term infections can also produce calves that appear normal but are uncoordinated. These calves are very susceptible to predation or misadventure.
The classic first sign of an outbreak occurs as the result of calves born with fused joints and flexed legs. The other common presentation with Akabane virus is an enlarged, dome-shaped head as a result of severe brain damage. Calves may appear blind and may wander aimlessly.
“We experienced a very mild Autumn and early Winter on the Tablelands which will have favored the midges carrying the virus”, said Lisa.
There is nothing that producers can do to reduce the deformities seen with Akabane virus if your herd is affected. Producers should also remember Akabane is a virus and not a genetic defect so it is not necessary to cull bulls that produced these calves. Females that have affected calves are also immune against future infections but may end up culled this year just on productivity terms.
