Farm algae warning

Victoria’s acting chief veterinary officer has warned farmers that blue-green algae in farm water supplies could poison stock and pets.

Dr Cameron Bell said seasonal conditions were ideal for algal growth in farm supplies, which often occurred in late summer and early autumn.

“Blue-green algal blooms typically appear as surface scum that looks like a suspension of green paint or curdled green milk,” he said.

“However, the colour might range from pale green to dark brown.

“Often an earthy smell will accompany a blue-green algal bloom.

“Deaths occur when stock drink toxins produced by the blue-green algae, often when it is concentrated on the down-wind side of a water supply and has formed a dense, surface scum.

“Animals that have consumed blue-green algal toxin can become ill very rapidly and die within 24 hours.

“Those that don’t die immediately often suffer severe liver damage.

“This might lead to the development of jaundice or photosensitisation over the next few days.”

Dr Bell said animals that recovered from these ailments might then suffer from chronic ill-thrift.

He said there is no specific treatment for blue-green algae poisoning.

“Blue-green algal poisoning should be suspected when animals are found dead and dying after access to an algal-contaminated water source,” he said.

“Dead animals might have their mouth, nose, feet and legs stained green by algae.

“Laboratory testing of the water supply for the presence of bluegreen algae, and a post-mortem examination of dead or sick animals by a veterinarian, will determine if the cause is blue-green algal poisoning.

“Checking stock water supplies daily for blooms remains the most effective way of preventing stock deaths.”

Dr Bell said another way to prepare was to develop a livestock water budget so farmers knew how much water stock required each day.

“Don’t forget to allow for high consumption during hot conditions,” he said.

“Identify an alternative water supply prior to the primary source of livestock drinking water being affected by a bloom.

“There might not be time to identify an alternative water source once the primary water supply is affected.”

Dr Bell said if farmers noticed a suspicious bloom, they should remove stock from the contaminated water source as quickly as possible and provide an alternate water supply.