Cyanobacterial poisoning threat grows with warming temperatures

NDSU Extension is starting to receive reports of blue-green algae in stock ponds used for livestock water. In addition, several water samples submitted to the NDSU Veterinary Diagnostic Laboratory have tested positive for cyanobacteria.

Cyanobacteria, also known as blue-green algae, can produce toxins that are

harmful to livestock, wildlife and people. “The growth of this bacteria is facilitated by the high temperatures common in July and August,” says Miranda Meehan, North Dakota State University Extension

livestock environmental stewardship specialist” Blue-green algae often occurs in stagnant ponds or dugouts with elevated nutrient levels, forming large

colonies that appear as scum on or just below the water surface. Live cyanobacterial blooms can be green, but also red or yellow, and often turn blue after the bloom dies and dries on the surface or shoreline. We expect to see the occurrence of blooms increase with temperatures during the next week.

Some species of cyanobacteria can be toxic when livestock and wildlife ingest them. Toxicity is dependent on the concentration of the toxins and the amount of water ingested.

Cyanobacteria can produce neuro and liver toxins. Signs of neurotoxin poisoning can appear within five minutes and up to several hours after ingestion. In animals, symptoms include weakness, staggering, muscle tremors, difficulty breathing, gastric-distress, convulsions, mental derangement and death. Often livestock are found dead before producers observe symptoms. If cyanobacterial poisoning is suspected as the cause of death, producers should check the edges of ponds for dead wildlife.

When collecting a water sample, follow NDSU Extension’s “Livestock Water Testing Guidelines” available at https://tinyurl.com/NDSU-LivestockWaterTesting.

For more information on sample collection and submission, contact your NDSU Extension agent. “Be sure to wear gloves because cyanobacteria can be toxic to humans,” Meehan

warns, “Collect a sample of the suspected cyanobacterial bloom from the surface

of the water and deeper in the water. The sample should be kept cool but not

frozen, and submit it to the NDSU Veterinary Diagnostic Laboratory or a commercial laboratory. The sample can be evaluated microscopically for algae, or the water can be analyzed for several of the toxins at commercial labs at a higher cost,” she adds.” Here are three ways producers can prevent cyanobacterial poisoning of livestock:

• Create a designated drinking area with minimal risk of cyanobacteria.

• Fence off the pond and pump water from the pond to the water tank.

• Use water from other sources following periods of hot, dry weather.

 For more information, check out “Cyanobacteria Poisoning” publication at http://tinyurl.com/NDSU-blue-green-algae.