As of late February, most of the southern Great Plains region was considered to be in long-term moderate to exceptional drought, according to the National Drought Mitigation Center. In fact, except for “normal” precipitation in June 2022, over 70% of the region has been rated in the moderate to exceptional drought categories each month since the dry period began (September 2021).
While feed availability and cost remain the primary factors driving herd liquidation, water availability and water quality are of increasing concern. In general, minerals and other contaminants concentrate in both surface and groundwater sources during long-term drought.
Water quality is a function of the concentration of elements or substances that may compromise livestock health and performance or result in toxicity. It is not uncommon to drill a new water well in Oklahoma only to discover “brackish” water. Brackish water generally contains high concentrations of salt and other potentially dangerous minerals or other compounds, such as sulfur and nitrate.
Total dissolved solids (TDS) concentration is a good place to begin in monitoring water quality and to consider the use of brackish water as a drinking water source for cattle. Most recommendations suggest cattle drinking water contain less than 5,000 parts per million (ppm) TDS. Water containing 5,000-7,000 ppm TDS should not be consumed by pregnant or lactating cattle and consumption of water containing greater than 7,000 ppm TDS should be avoided altogether.
We have had several reports of water sulfur concentration increasing in western Oklahoma groundwater sources. While maximum tolerable sulfur concentration in drinking water for cattle is not well defined, the National Academy of Sciences, Medicine and Engineering recommends less than 500 ppm (or mg/L) for calves and less than 1,000 ppm for adult cattle. Consideration must also be given to forage and concentrate feed sulfur content in combination with water sulfur content.
The good news is that water quality is not difficult nor expensive to test. The Soil, Water and Forage Analytical Laboratory at Oklahoma State University (OSU) charges $15 per livestock water sample. For that, you get sodium, calcium, magnesium, potassium, iron and zinc levels; electrical conductivity, pH, nitrate-nitrogen, chloride, sulfate, TDS and hardness.
Here is how you can obtain and ship a quality water sample to a testing laboratory:
• Most county Extension offices can assist with this process.
• Obtain a clean 4 oz. plastic water bottle (the laboratory does not recommend glass bottles). A wide-mouth bottle with a screw-on lid works well.
• Go to the water source that you want to test.
• Fill the water bottle halfway, shake and rinse the bottle and pour out.
• Repeat the previous step three more times.
• Finally fill the bottle as full as possible. Cap it, leaving as little air space as possible.
• Be sure the bottle is well labeled, and the laboratory’s submission form is completed and included in the shipping container.
Just because a water quality test comes back from the laboratory as “brackish,” does not mean it cannot be used for livestock. Once the chemical composition is determined, it may be possible to blend the brackish water source with a more purified source, such as rural water, to dilute the minerals down to a safe level. Be sure to consult your veterinarian and a nutrition expert to investigate and monitor water quality in concert with your supplementation program. — David Lalman and Marty New, OSU Extension specialists
