With no rainfall to recharge stock dams, the concentration of sulfates in the water is increasing to dangerous levels, says Adele Harty, South Dakota State University Extension cow/calf field specialist.
Some cattle have been poisoned and died.
"It is critical to test the water," she says.
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 levels greater than 3000 ppm, sulfates are acutely toxic
"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 says. 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 says. "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. It does not clump together like more conventional algae. Look for it on the edges of a dugout or body of water. The best method to protect their cattle is to fence off polluted water.
"It is challenging to get rid of and unpredictable," she said.
If you think livestock died from consuming blue green algae, Harty suggests having a veterinarian verify it.
Russ Daly, SDSU Extension Veterinarian says if cattle have consumed water high in sulfates they may have symptoms ranging 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
To ensure that your water source is safe for livestock, Harty recommends testing water
"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 says.
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.
For more information contact one of the following Extension Regional Centers:
- Aberdeen -- 605-626-2870
- Lemmon -- 605-374-4177
- Mitchell -- 605-995-7378
- Pierre -- 605-773-8120
- Rapid City -- 605-394-1722
- Sioux Falls -- 605-782-3290
- Watertown -- 605-882-5140
- Winner -- 605-842-1267