Livestock producers need to test their water for sulfates, says Adele Harty, South Dakota State University Extension cow-calf field specialist.
"There have been some ranchers who have lost cattle in the western part of the state due to water quality issues," Harty said. "This means it is even more critical to test the water before turning cattle into a pasture."
As the drought continues, Harty says water quality issues continue to worsen as low precipitation and increased evaporation from wind and high temperatures increase the risk of high sulfate water.
"With no rainfall to recharge the dams, the concentration of sulfates continues to increase. Ranchers need to test wells, as well as stock dams," Harty said.
Harty explains that excess sulfate leads to problems in livestock ranging from reduced water intake to poisoning and death.
"If poor water quality is a problem, it can result in reduced water intake which in turn will cause animals to reduce feed intake, leading to reduced performance," Harty said.
Based on data from several research projects, Harty said levels of sulfates that will reduce livestock performance are 2000 - 3000 ppm. If cattle are consuming water with a sulfate level of 1500-2500 ppm it could cause temporary diarrhea. At higher concentrations of sulfate, i.e. levels greater than 3000 ppm, sulfates are acutely toxic, contributing to polioencephalomalacia (PEM). This basically means it causes softening and deterioration of brain tissue.
High sulfate water & blue green algae
Harty explains that water that is high in sulfate salts can be found throughout the western portions of the Northern Plains, including the Dakotas, Nebraska, Wyoming, and Montana.
"Water high in sulfates will have a bitter taste. Animals will avoid it if better quality sources of water are available, but will be forced to consume it if that is their only choice, especially in hot weather," she said.
She adds that non-native cattle are at greater risk than those raised on sulfate water.
"There is a higher incidence of morbidity and mortality in naïve animals, brought in from other states, than in animals that have been drinking high sulfate water their entire life. Preliminary research suggests there is genetic variation among individual animals in a herd for susceptibility to high sulfate levels," Harty said. "Susceptible animals have likely been eliminated - died or were culled for poor performance - in native herds that have been exposed for generations to high-sulfate water, but naïve herds will be likely to have susceptible individuals."
Along with sulfates, the hot dry weather provides a perfect environment for production of blue green algae. Harty says if a body of water is infected with this algae and it is consumed by livestock, death is certain.
She says the algae is difficult to detect because it does not clump together like more conventional algae. Livestock owners should look for it on the edges of a dugout or body of water. If they find blue green algae, Harty says the best method to protect their cattle is to fence it off.
"It is challenging to get rid of and unpredictable," she said.
If a livestock producer thinks their livestock died from consuming blue green algae, she encourages them to contact their vet for verification.
Signs to watch for
Dr. Russ Daly, Extension Veterinarian says if cattle have consumed water high in sulfates and may have PEM, symptoms range from reduced water and feed intake, lethargy, star-gazing, head-pressing to blindness, staggering, going down and possibly end in death. He says cattle can progress through this range of symptoms rapidly without treatment and recommends working with your local veterinarian in the treatment of PEM.
Unfortunately, Harty says ranchers with high-sulfate water have limited options. She says if rural water is available; the return on investment in pipelines would be well worth the cost.
"If you are in an area that is not served by a rural water district, drilling a new well is another option, but it is expensive and has the risk that the water may also have high sulfate levels," Harty said.
Another option, though extremely expensive, is to haul low-sulfate water to the pastures. Unfortunately, this may be the only viable option, at least temporarily.
Sulfate testing available at SDSU Regional Extension Centers
To ensure that your water source is safe for livestock, Harty recommends testing water periodically throughout the summer.
"Some water that is muddy and murky may be OK, while other water that is clear may be quite dangerous. Many are surprised to hear this, but clear water often means there's little to no life because of high sulfates," she said.
SDSU Extension Regional Centers have electroconductivity (EC) meters, which measure total salt content in water. This is an indicator of sulfate levels. If the EC meter reads greater than 3,000 ppm total dissolved solids, SDSU Extension recommends additional testing at an accredited laboratory to determine the actual sulfate level.