Cyanobacteria, also known as blue-green algae, can be toxic to livestock and wildlife. They live in stagnant ponds or dugouts, forming large colonies that appear as scum on or just below the water surface.

Cyanobacteria produce toxins that can kill people, livestock and wildlife.

Usually, the algae blooms aren’t a problem until late summer or fall, but when there’s a drought, they can get bad early.

By early July in North Dakota, blooms were testing positive for cyanobacteria and were responsible for the deaths of at least six animals.

Here’s what Miranda Meehan, North Dakota State University veterinary toxicologist, says you need to know about blue-green algae to protect yourself and your livestock:

1. Live cyanobacterial blooms are usually green, but they also can be red or yellow. They often turn blue after the bloom dies and dries on the surface or shoreline.

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

3. Cyanobacteria can produce neuro and liver toxins. Signs of neurotoxin poisoning can appear within five minutes to up to several hours after ingestion. In animals, symptoms include weakness, staggering, muscle tremors, difficulty in breathing, convulsions and, ultimately, death.

4. Animals affected by liver toxins may exhibit weakness, pale-colored mucous membranes, mental derangement, bloody diarrhea and, ultimately, death. Typically, livestock are found dead before producers observe symptoms.

5. If cyanobacterial poisoning is suspected as the cause of death, check the edges of ponds for deceased wildlife. Put on gloves and collect a sample of the suspected cyanobacterial bloom from the surface of the water and deeper in the water. Keep the sample cool but don’t freeze it, 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. For more information on sample collection and submission, contact your county agent or the NDSU Extension Service.

6. If you lose livestock due to cyanobacteria poisoning, you may be eligible for compensation through the USDA Livestock Indemnity Program. Compensation is provided for the first episode of deaths linked to a specific water source. After that, producers must implement management practices to prevent additional losses. Producers also must report losses to the USDA Farm Service Agency within 30 days after the loss is apparent.

Prevention steps
To prevent cyanobacterial poisoning, Meehan recommends:

• reducing nutrient levels entering the water source by implementing a nutrient management plan or establishing buffer strips with perennial species

• creating a designated drinking area where the risk of cyanobacteria is minimal

• fencing off pond and pump water from the pond to the water tank

• providing other water sources following periods of hot, dry weather

• adding copper sulfate to water if the source has a history of algae blooms

Apply 2 pounds of copper sulfate per acre-foot of water, which is equal to a rate of 8 pounds per 1 million gallons. Livestock must be fenced out of treated water sources for at least 10 days.

For more information, see NDSU Extension Service’s Cyanobacteria (Blue-green Algae) Poisoning publication at tinyurl.com/NDSU-blue-green-algae.

Source: NDSU Extension