Blue-green algae poses threat to animals

By Bianca Hall

Nov 30, 2022

Warning: “Blue-green algal blooms typically appear as surface scum that looks like a suspension of green paint, often with an earthy smell. However, the colour may range from pale green to dark brown,” Agriculture Victoria senior veterinary officer Dianne Phillips said. Photo by Contributed

The recent flooding event combined with warmer weather conditions has produced favourable conditions for blue-green algae to thrive in farm water supplies and standing floodwater.

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Agriculture Victoria senior veterinary officer Dianne Phillips said blue-green algae could result in the poisoning of livestock and dogs when consumed.

“As there is no specific treatment for blue-green algae poisoning, producers should check standing bodies of water and farm water supplies daily for blooms, as this remains the most effective way of preventing stock deaths,” Dr Phillips said.

Animals may appear ill very rapidly, develop a staggering gait, collapse, convulse and die within 24 hours, depending on the toxicity and concentration of the bloom.

Those that don’t die immediately often suffer from severe liver damage, leading to jaundice or photosensitisation.

If a suspicious bloom is noticed, the water supply should be quickly isolated and a safe alternate water supply provided.

Dr Phillips said identifying an alternative water supply, prior to their primary source of livestock drinking water being affected by a bloom, was ideal.

“There may not be time to identify an alternative water source once the primary water supply is affected,” Dr Phillips said.

“We recommend laboratory testing of the water supply for the presence of blue-green algae and a post-mortem or examination of dead or sick animals by a veterinarian.”

Contaminated water should not be used to irrigate or come in contact with plants being grown for food, particularly those mostly eaten raw such as apples, grapes, tomatoes, strawberries, cabbages and other salad greens.