The H5N1 bird flu strain has reached Australia’s shores but it’s “business as usual” for the dairy industry, leaders say.

Australia’s biosecurity is on high alert this week after four confirmed H5N1 bird flu cases across Western Australia and South Australia.

There were more than 400 reports of sick or dead birds in 10 days to Monday.

Western Australia and South Australia are home to two of Australia’s smallest dairying regions, with about 100 (2.6 per cent) and 116 (4.4 per cent) dairy farms respectively.

WA Farmers Dairy Council chairman Peter Evans manages 900 milking cows at Busselton, about 20km away from a confirmed case.

“We’re aware and alert, we can’t do much,” he said.

“The ministers said (last year) it wasn’t a matter of if, it’s a matter of when.

“We expected it to come from the north, not the south,” Mr Evans said.

“Farmers aren’t panicking, there’s nothing to worry about yet.”

Dairy cattle can contract H5N1 bird flu, with reported symptoms including a severe drop in milk production, loss of appetite, lethargy, fever or colostrum-like thickened milk.

Dairy Australia and DAFF finished a risk assessment on H5 bird flu and Australia’s dairying industry in September. It found a low risk for the industry, but acknowledged there remained “significant knowledge gaps” in understanding of the virus at the time.

The US first found H5 bird flu in dairy cows in March 2024. The virus spread across farms through exposure to infected milk, with 1145 cattle affected across 20 states since.

But the Dairy Australia assessment set the US apart for its larger, intensive operations compared to Australia’s mostly pasture-based systems with fewer interactions between farms.

Australian Dairy Industry Council chairman Ben Bennett said the H5 genotypes linked to the US dairy cattle outbreaks were not found in Australia, and the risk remained low.

“There is no evidence from the current situation that would alter that assessment,” he said.

South Australian Dairyfarmers Association president Robert Brokenshire said the state government had worked quickly with dairy industry leaders, hosting two meetings so far.

“It’s business as usual (for dairy farmers),” he said. “The chances of it mutating into dairy cattle is very, very low.

“If you see anything unusual occurring on your farm, whether it’s a sick or dead bird … notify the animal disease hotline, and let them instruct you.”

Call the Emergency Animal Disease Hotline: 1800 675 888.