CATTLE in areas of Queensland, NSW and the Northern Territory that have been exposed to solid rain over the past month are already being impacted by heavy external parasite and disease challenges.
Three day sickness is being reported across wide areas of central, northern and southern Queensland, and buffalo fly populations have exploded in many areas fortunate enough to get rain since mid-January. Heavier cattle appear to be the most susceptible to three-day, judging by social media comments this week. Some suggested this was because they were not exposed to the BEF virus at a young age, building resistence, because drought conditions held the disease at bay.
Three day sickness, or bovine ephemeral fever, is a viral disease of cattle that is spread by mosquitoes and biting midges. It occurs across northern Australia and along the eastern seaboard south to the NSW-Victorian border.
Central Queensland veterinarian Alan Guilfoyle has had a number of clients reporting three-day outbreaks this month, across a wide area.
Dr Guilfoyle said he had lost cattle in his own herd earlier this week.
“As soon as buffalo fly numbers start to breed up after rain, the culicoides midges carrying three-day virus also start to breed up, and cattle start to succumb,” he said.
“The outbreaks always follow the insects, wherever there is hatchings going on.”
He said buffalo fly and other insect infestations were ‘savage’ this month, since the rain.
“But in fact we haven’t got into the peak season for three-day yet. From my experience, it is not a mid-summer disease, but a spring and autumn disease, because of the heat factor. So there could be worse to come.”
Dr Guilfoyle said many producers failed to recognise the sub-clinical impact of buffalo fly, sandflies and three-day on weight-gain and herd productivity. Rather than vaccinating annually, some producers tended to vaccinate weaner bulls only for three-day, and then rely on natural immunity later in life.
A few years ago, he did some sums, based on a mob of 500 steers, vaccinated for botumism, tick fever, three-day and five-in-one.
“At current market prices, you’ve only got to 5-7 grower cattle from a mob of 500 to cover the cost of vaccination. It’s cheap insurance, and that does not account for lost productivity and weight loss from the cattle that survive,” he said.
Dung beetle decline
Dr Guilfoyle said buffalo fly since the rain this year were likely to be worse than normal, because of the decline in beneficial dung beetle populations during the drought.
“I haven’t seen a dung beetle for ages on my block. Everything has to go through a recovery period after extended drought, and dung beetles are no different. Until then, fly challenge is likely to be worse than normal.”
Tick populations, also were likely to build up during 2020, having been held in check for the past two years by extremely dry conditions.
Toowoomba-based buffalo fly back-rubber manufacturer Keiran Gentry says demand for his products has been ‘unbelievable’ since the rain started last month.
His AC Back-rubbers business has been ‘run off its feet’ since January, he said.
“Because it’s been so dry for so long, there’s been no real buffalo fly challenge. But the recent high temperatures and prolonged wet, humid conditions have been perfect for numbers to rapidly breed up.”
Demand for back-rubbers and application products was coming from all over Queensland, the northern Territory and into northern NSW, Mr Gentry said.
“Some areas further south started to get some fly challenge back as far as November, after they had a few storms – especially closer to the coast. But since January, demand has spread everywhere. We literally cannot pack enough of our oil-based Cattle Coat product, to keep up with demand.”
Further south, the NSW Department of Primary Industries yesterday urged producers to vaccinate their livestock following confirmation of the first case of anthrax for 2020.
The detection occurred on the NSW Central Tablelands on a property with no previous record of anthrax. The affected animals were ewes that had not been vaccinated for anthrax.
Biosecurity measures at the affected property, including stock movement restrictions and the vaccination of remaining livestock were immediately imposed.
DPI Senior Veterinary Officer, Dr Graham Bailey said while there are no general public health risks or trade implications from the detection, it served as a timely reminder.
Cases of anthrax in NSW tend to occur in an area which runs through the centre of the state, between Bourke and Moree in the north, to Albury and Deniliquin in the south.
“Anthrax can be prevented by annual vaccination of cattle and sheep. Producers in high risk locations are encouraged to consider vaccination,” Dr Bailey said.
Central Tablelands Local Land Services District Veterinarian, Amy Masters said those wishing to vaccinate can apply to their Local Land Services District Veterinarian.
“Once approved you can order the vaccine through your local rural supplier or private veterinarian,” Dr Masters said.