By Scout Nelson
Hot summer weather increases the risk of toxic cyanobacteria, commonly called blue-green algae, developing in ponds, dugouts, lakes, and other water sources. These harmful blooms can produce dangerous toxins that affect livestock, wildlife, and people, making careful water management important during warm months.
North Dakota State University (NDSU) Extension advised agricultural producers to closely monitor water sources as temperatures rise. Miranda Meehan, NDSU Extension livestock environmental stewardship specialist, explained that warm to hot weather creates ideal conditions for cyanobacteria growth.
“The hot, dry conditions projected for July are ideal for the growth of cyanobacteria,” says Meehan.
The North Dakota Department of Environmental Quality maintains a list of cyanobacteria blooms on lakes and reservoirs. For a list of reported blooms, visit: https://deq.nd.gov/WQ/3_Watershed_Mgmt/8_HABS/Habs.aspx.
Cyanobacteria grow quickly when excess nutrients, especially nitrogen and phosphorus, enter surface water. Nutrients from manure and commercial fertilizers can wash into ponds and lakes if they are applied at the wrong rate or time. These nutrients encourage the rapid growth of harmful algae and other microorganisms.
Blue-green algae are commonly found in stagnant water with high nutrient levels. They often form thick layers of scum on the water surface and just below it. Blooms usually appear green but may also look red or yellow. After the algae die and dry along the shoreline, they often turn blue.
Some cyanobacteria produce toxins that can seriously harm animals. The severity depends on the species affected, the toxin level, and the amount of contaminated water consumed. Neurotoxins may cause weakness, muscle tremors, difficulty breathing, convulsions, and death within minutes or several hours. Liver toxins may cause weakness, pale gums, mental confusion, bloody diarrhea, and death. In many cases, livestock die before visible symptoms are noticed.
“A veterinarian can determine which samples would be appropriate for each situation,” says Dr. Jake Galbreath, NDSU Extension veterinarian and livestock stewardship specialist.
When collecting a water sample, follow NDSU Extension’s livestock water testing guidelines at ndsu.ag/watertesting-26.
If poisoning is suspected, producers should wear gloves while collecting water samples because cyanobacteria can also harm humans. Samples should include water from both the surface and deeper areas, remain cool but not frozen, and be submitted to the NDSU Veterinary Diagnostic Laboratory or another commercial laboratory for testing.
NDSU Extension water engineer Laxmi Prasad recommends several prevention measures, including reducing nutrient runoff with nutrient management plans, planting buffer strips, fencing livestock away from ponds, pumping water into tanks, using cleaner water sources after hot, dry weather, and drawing water from below the surface where bacteria are less concentrated.
“Unless steps are taken to reduce the nutrient load and minimize the potential for nutrients to enter the water body, the risk for cyanobacterial blooms will continue,” says Prasad.
Photo Credit: pexels-adam-sondel
Categories: North Dakota, Livestock