Blue-green algae are actually a type of bacteria, Cyanobacteria. “The bacteria contains chlorophyll, which converts sunlight into energy allowing the bacteria to grow, just as plants do,” said Dr. Dave Sparks, area food-animal quality and health specialist at Oklahoma State University.
Dan Obrecht, senior research associate in the school of natural resources at the University of Missouri, said that this particular type of blue-green algae differs from other algae because their cell structure is similar to a bacteria’s cell structure.
“When the water is warmer, the bacteria multiply faster therefore giving off more toxins,” Sparks said. An additional reason for more occurrences of the bacteria this summer is the lack of rain, resulting in lower pond levels and stagnant water, which causes higher toxicity levels in the water.
The broadest categories of cyanobacterial toxins include hepatotoxins, neurotoxins, dermatotoxins and endotoxins. Respectively, these interrupt the proper functioning of the liver and kidneys, nervous system, skin and gastrointestinal system. “Cases involving mortality are rare, or at least rarely reported or identified properly,” said J. Thad Scott, assistant professor in the crop, soil and environmental sciences department at the University of Arkansas.
“Producers need to realize that appearance and odor of the water are not good indicators of whether or not your pond has the Cyanobacteria,” Sparks said. “The bacteria can form in any color, not just blue and/or green. The one consistency to rely on is that there will be a type of pond scum that looks like someone literally poured a bucket of paint on top of the water.”
Proper pond management is the most effective means to minimize risks to livestock. “Like land plants, the biomass of all photosynthetic pond organisms depends on nutrient availability,” Scott said. “Managing your pond so that it receives minimal nutrient inputs is advisable. Also, depending on the size of the pond there are many types of mixing devices such as bubblers or aerators that help create turbulent water conditions. This helps avoid large cyanobacterial blooms.”
If producers want to find out if they actually have Cyanobacteria in their pond(s) or water sources, they need to contact their veterinarian or local extension agent to find a diagnostics lab to test their water. A sample of water from the pond should be taken and sent to the lab if anyone suspects high levels of the Cyanobacteria.
“If toxicity is found in the pond, producers need to immediately fence off the pond or water source so no animals can get to the water,” Sparks said. “If the producer cannot fence off the pond they need to provide another water source, such as a stock tank with water from a different water supply.”
Producers can attempt to eliminate the bacteria causing toxins by adding copper sulfate to the pond. However, this must be done with caution and may end up causing more harm than good if not done properly. Thus, it is probably best to wait for a good amount of rain to cause runoff, a natural eliminator of the bacteria and its’ toxicity. Either way it is best to keep the livestock away from the infected water source at least 10 days to make sure the toxicity level is reduced to a safe level.
