Monitor Livestock Water Quality Throughout The Grazing Season

Having access to good-quality water is one of the limiting factors for cattle in most grazing systems.

“Across the region, many livestock producers depend on surface water sources, such as ponds and dugouts to provide livestock water,” says Miranda Meehan, North Dakota State University Extension livestock environmental stewardship specialist. “Unfortunately, the quantity and quality of surface waters can fluctuate greatly throughout the grazing season, depending on weather.”

The quality of water impacts cattle intake and weight gain. Studies have reported improved gains by as much as 0.24 pound per day in yearlings and 0.33 pound per day in calves drinking good-quality water.

Thanks to high levels of runoff, recent water quality screenings conducted by NDSU Extension have found sources acceptable for livestock use. However, the outlook for June shows a high probability for drier and hotter-than-average conditions across the state, which could lead to declines in water quantity and quality. These conditions create greater challenges for producers. As water quantity decreases, the potential for toxicity increases.

Many water sources in the state naturally contain salts, which are dissolved minerals or solids. When surface waters become low, the mineral component of the water becomes more concentrated because minerals do not evaporate with the water. Of particular concern are increased concentrations of total dissolved solids (TDS) and sulfates.

Elevated concentrations of TDS and sulfates can be toxic to livestock, resulting in decreased performance, abortions, blindness, central nervous system disorders and death, says Meehan.

For most classes of grazing livestock, the TDS in the water should be less than 5,000 parts per million (ppm). Sulfate is part of the TDS. The recommended concentration should be less than 500 ppm for calves and less than 1,000 ppm for adult cattle.

Ranchers should monitor TDS and sulfate levels throughout the grazing season because weather and other factors can influence water quality. NDSU Extension specialists recommend a couple tools to aid in monitoring water quality, a hand-held TDS meter and sulfate test strips. Both these tools are affordable and easy to use. If the screening indicates the TDS is greater than 4,500 ppm and/or sulfates are greater than 800 ppm, submit a sample to a lab for additional analysis.

Hot, dry conditions also increase the risk for cyanobacteria (blue-green algae) blooms that can produce toxins that are harmful to livestock, wildlife and people. Toxicity is dependent on the species consuming the water, the concentration of the toxin or toxins and the amount of water ingested.

The best method for monitoring cyanobacteria is visually, says Meehan. However, this can be difficult due to how rapidly a bloom can develop and ranchers’ ability to check water frequently. One potential solution is to use a camera to monitor water locations.

If a bloom is observed, ranchers should remove livestock immediately and submit a water sample for testing. The sample can be evaluated microscopically for potentially toxic species of cyanobacteria, or the water can be analyzed for several of the toxins at commercial labs at a higher cost.

As the grazing season progresses, continue to monitor water to ensure livestock have adequate, good-quality water, Meehan advises.