A Saskatchewan livestock specialist says visually inspecting water is not a reliable way to determine its suitability
Considering that a lactating cow needs between 55 and 61 litres of water each day during the summer, that water needs to be good.
Water quality issues often arise, sometimes causing herd health concerns and livestock deaths, but one case remains fresh in the minds of many people.
In 2017, more than 200 cattle died in the community pasture at Shamrock, Sask. The animals died from excess sulfates and total dissolved solids levels in the water source.
Catherine Lang, livestock and feed extension specialist based in Moose Jaw, said testing water sources is critical. And just because the water looks like it came out of a tap doesn’t mean it’s suitable, she said.
During a presentation as part of Ag in Motion Discovery Plus, she showed a photograph of four clear jugs containing water. From left to right the water in the jugs went from clear to dark.
The water was taken from Old Wives Lake in the summer of 2016. Lang said while the instinct might be to use the clearest water the laboratory test results showed the opposite.
The first jug had 1,731 milligrams per litre of sulfates, and the second contained 2,056 mg/L. These numbers indicate the first was borderline for use and the second was too high, according to current guidelines.
But the third jug containing the green water contained only 21 mg/L and the fourth jug with yellow-brown water contained only 15 mg/L.
“Three and four are sitting really awesome,” Lang said, noting they aren’t pretty but they are definitely safer for cows to drink.
Sulfate levels below 500 mg/L are considered safe, while levels between 500 and 1,000 mg/L have the potential to cause trace mineral deficiencies in high-performing cattle such as dairy cows and beef cows that are milking and trying to rebreed, she said.
Water with between 1,000 and 2,000 mg/L can be used but with a lot of caution and the use of chelated mineral. Anything above 2,000 mg/L is not recommended.
A study completed at the Livestock Forage Centre of Excellence earlier this year found cattle in well-controlled environments could tolerate higher levels than that. Lang said a second study scheduled for 2021 will more closely resemble pasture conditions and offer more detailed results.
She encourages cattle producers to test water sources in late May or early June to obtain a baseline and then monitor the water through the growing season.
Sources can vary even within pastures, she said.
“We’ve seen some that are 100 feet apart and one can be toxic and one can be really good,” she said. “It all has to do with different amounts of runoff and where those dugouts are placed.”
Tests should be done as close as possible to where the cattle drink. If using a well, the test should be done close to the watering bowl. If using a dugout, get a clean container as close to where cattle most like to drink and scoop the water out.
One litre is required.
Saskatchewan Agriculture regional offices staff can test for conductivity in the office, but the more detailed information comes from sending that sample on for assessment at the Roy Romanow provincial lab in Regina. The test is free for cattle producers who have a premises identification number and as long as the water is for livestock.
Lang said producers must remember that water quality can change quickly. A dugout near Old Wives Lake tested 1,480 mg/L on April 30 this year, 1,857 mg/L a week later and more than 2,000 a week after that. By June 18, it was already at 3,850 mg/L.
She added that in 2017 nearly half the water brought into the Moose Jaw office was not acceptable. For the last two years that has dropped to just over 20 percent.
That doesn’t mean the water is getting better.
“It could mean producers are not sampling the really bad ones anymore and they’ve just fenced them out,” she said.