Oklahoma-Farm-and-Ranch_543839

OKFR 12 | AUGUST 2026 D By OKFR Sta Is the Pond Safe for Livestock? During the hottest part of summer, a farm pond can look like a welcome source of water. Cattle may be standing belly- deep along the bank, and the pond may still hold enough wa- ter to appear dependable. How- ever, appearance alone does not reveal whether that water is safe. Hot weather, limited rainfall and falling pond levels can cre- ate water-quality problems. As water evaporates, salts, miner- als, nutrients and other sub- stances may become more concentrated. Warm, still water can also encourage the growth of blue-green algae, some forms of which can produce toxins ca- pable of killing livestock. Water is sometimes treated as an afterthought compared to grass, hay and supplemen- tal feed. In reality, livestock need a dependable supply of clean water to maintain feed intake, regulate body tempera- ture and support production. Poor-quality water may reduce consumption and performance even when it does not cause an obvious case of poisoning. A pond that has watered cattle for years should not au- tomatically be considered safe under every set of conditions. Producers should pay particu- lar attention during drought, extreme heat or any period when the water level drops sig- ni cantly. Watch the Water and the Livestock One of the most serious late- summer concerns is a bloom of cyanobacteria, commonly called blue-green algae. These organisms are naturally present in many bodies of water, and most do not produce dangerous toxins. The risk increases when certain toxin-producing species multiply rapidly under favorable conditions. According to Oklahoma State University Extension, toxic blue- green algal blooms typically develop in standing water fol- lowing periods of hot, dry and calm weather. Nutrients such as nitrogen and phosphorus can contribute to excessive growth. Those nutrients may enter a pond through manure, fertilizer runo , soil erosion and decaying vegetation. A suspicious bloom may make the water appear bright green, blue-green, pea-soup green or even brownish. Scum, foam or mats may collect along the shoreline, particularly where the wind pushes oating mate- rial into one area. Some blooms resemble spilled paint. Not every green pond is poi- sonous. Common aquatic plants and harmless forms of algae can also change the color or surface of the water. Unfortunately, it is usually impossible to deter- mine whether a bloom is toxic simply by looking at it. A pond can contain toxin-producing cyanobacteria without display- ing every commonly described warning sign. Owners should keep live- stock, horses, pets and people away from water that has an un- usual color, heavy surface scum, a bad odor or unexplained dead sh or wildlife nearby. Livestock should not be allowed to drink from another portion of the same pond under the assump- tion that the water is safe there. Wind can move a bloom, and toxin concentrations may vary throughout the pond. Blue-green algae can produce toxins that a ect the nervous system or liver. Depending on the toxin and the amount con- sumed, affected animals may develop weakness, staggering, difficulty breathing, tremors, convulsions, diarrhea or col- lapse. In severe cases, animals may be found dead near the water before the owner realizes anything is wrong. Treatment is often unsuccessful, making prevention especially important. Any suspected poisoning should be treated as an emer- gency. Remove the herd from the water source without driv- ing or unnecessarily stressing animals that may already be a ected. Provide another clean water supply and contact a vet- erinarian immediately. The local county Extension o ce can also help determine where and how to submit an appropriate water sample. Blue-green algae is not the only potential problem. Pond water may contain elevated levels of dissolved salts, sul- fates, nitrates, bacteria or other contaminants. Runo can carry manure, fertilizer, pesticides and organic matter into the pond. Low water levels can make some of these problems more pro- nounced because the remain- ing water becomes increasingly concentrated. Water with excessive dis- solved solids may taste bitter or salty, reducing the amount animals consume. Depending on the substances involved and their concentrations, poor- quality water may contribute to diarrhea, reduced feed intake, poor weight gain or other health concerns. Young animals and livestock that are not accus- tomed to the water may be more vulnerable. Producers should also watch the cattle themselves. Are they reluctant to drink? Are they crowding around a different water source? Has feed intake or weight gain declined without an obvious explanation? Are several animals experiencing digestive problems? Changes involving multiple animals can provide an early clue that feed or water should be investigated. OSU Extension recommends collecting a representative sam- Water is sometimes treated as an afterthought compared to grass, hay, and supplemental feed. (Courtesy photo)