Use caution when testing water quality with hand-held meters

The best time to test is now, says SaskAg livestock and feed extension specialist

Livestock and feed specialists with the Saskatchewan Ministry of Agriculture have learned that not all methods of testing water quality are equal, especially when it comes to total dissolved solids and sulphates.

Leah Clark, livestock and feed extension specialist with the Saskatchewan Ministry of Agriculture, took part in a study comparing the accuracy of water quality measurements taken by hand-held meters to that of laboratory testing. This study was conducted by provincial specialists with the help of Phil Bailey and staff at the Roy Romanow Provincial Laboratory, as well as the Western College of Veterinary Medicine at the University of Saskatchewan.

Clark, who works out of the Agriculture Knowledge Centre in Moose Jaw, Sask., first became interested in the importance of water quality in livestock production when working in the Weyburn office, where problems with water quality were frequent. “I think it’s kind of the forgotten nutrient,” she said. “It wasn’t getting the recognition it deserved, and I think it was causing more production issues than producers realized.”

One of the most common water quality issues that Clark encounters is increased sulphates in exposed water, which can intensify in the summer. “That is just purely due to heat, dryness, wind causing evaporation, and what evaporates is the water and it condenses the minerals and the other water constituents left in,” she said. “We know we have elevated sulphates around Saskatchewan, particularly in the south, and so last year, there was that hot, dry weather and those dugouts… really condensed in sulphates and total dissolved solids.”

In samples of Saskatchewan dugout sulphates obtained and analyzed by the Roy Romanow Provincial Laboratory, 40 per cent of the samples fell into the Good (0-500 milligrams per litre) and Satisfactory (500-1,000 mg/L) categories, 12 per cent were in the Caution category (1,000-2,000 mg/l) and 49 per cent were in the Not Acceptable (2,000 plus mg/l) and Death (7,000 plus mg/l) categories.

One particularly deadly instance in the province made headlines in July 2017 when 200 head in a community pasture with poor water quality died of dehydration and heat stress. The total dissolved solids (TDS) in this water source reached 33,400 mg/l. A TDS of 5,000 mg/l and higher is considered unacceptable for cattle and will lead to health problems and or death. The level of sulphates was 24,000 mg/l, much higher than the threshold for death in cattle.

While extremely high levels of sulphates in water can be deadly, Clark says the most commonly seen effects relate to metabolic interference. There is a wide range of symptoms to watch for, some of which can be subtle or difficult to identify.

Appearances are deceiving when it comes to water quality as evidenced by the sulphate levels in these 2016 samples: 1,731 mg/l in jug 1; 2,056 mg/l) in jug 2; 21 mg/l in jug 3 and 15 mg/l in jug 4. Photo: Supplied

“What happens with elevated sulphates is it starts off by causing trace mineral deficiencies,” she explains. “In particular, it affects magnesium, copper and zinc, and with those deficiencies, the first symptoms we see are lightening of the hair coat or changes in the hair coat from more curly or more kinked, some people say.”

Facing trace mineral deficiencies, an animal’s immune system weakens. More cases of foot rot and pink eye could be one symptom.

“From there we start to see more dramatic things, like conception rates declining, and in extreme cases, polio, which is essentially a thiamine or B vitamin deficiency in the animal, and that’s when you see neurological symptoms.”

Test wisely

The 2017 Western Canada Cow-Calf Survey suggests 60 per cent of producers don’t lab test the quality of their water sources. Clark isn’t surprised by this finding. She often encounters producers who’ve never tested their water.

“Water is just one of those things that doesn’t get tested regularly, and if it gets tested, it’s usually through Sask. Health and it’s usually just a bacterial panel, so the minerals are oftentimes overlooked.”

She recommends testing water sources even when there are no visible issues. “Both humans and animals can adjust to certain high minerals in their body, but it still can be impacting body function,” she said. “The best time to test is now, if you haven’t tested before.”

The testing method used matters, however. In their study, Clark and other specialists took hundreds of hand-held electroconductivity measurements, then compared the results to a comparable lab analysis. What they noticed was some hand-held meter readings were less accurate when compared to the lab results.

“This is one of the issues that we are worried about, because guys are going out and saying, ‘okay, we can get an eletroconductivity meter and we can test our water,’” she said. “In theory, yes, you can, and that’s great, but what we’re seeing is that there are some big inaccuracies with some of the hand-held readers.”

Proper upkeep of the meter can affect the readings. “A hand-held reader needs to be cared for, it needs to be calibrated, the probe needs to be cleaned, and if it’s not taken care of, it can really throw off the reading.”

The more troubling explanation for the inaccuracies, though, has to do with the water’s conductivity, or ability to hold an electronic charge, which rises the higher the ionic concentration. Hand-held meters use a conversion rate to get a TDS measurement from the conductivity reading. However, conductivity isn’t always related to TDS, as different types of ions vary in the way they carry electricity, meaning each water sample will read differently.

“Some of the electroconductivity meters that producers can get automatically convert to total dissolved solids, and what those meters are doing is they’re just reading electroconductivity and converting to total dissolved solids. That conversion factor usually is around 64 to 71 per cent, so that TDS conversion, from what we saw last year, is way off,” said Clark.

In a group of more than 500 water samples, they found that the average conversion factor from electroconductivity to TDS was 91 per cent. “The range was from 60 per cent to 115 per cent,” she said. “So when relying on that total dissolved solids reading from those meters, be careful. Proceed with caution, because in Saskatchewan, our waters are showing us that they’re not 64 per cent total dissolved solids from conductivity.”

It’s also important to remember that the water’s appearance isn’t always an indicator of quality. For example, a brown tinge may be due to iron, which doesn’t cause major issues in cattle.

“Sometimes people get grossed out with green. Well, there’s a lot of beneficial green growth that can happen in a dugout,” she said. “Clarity of water does not always correlate with good quality of water. In fact, a lot of those green things only grow in good quality water.”

For producers who suspect that water quality is affecting their cattle, Clark stresses the importance of first testing the water. Provincial agriculture offices can help, as specialists can assist producers with testing. “Once we get that test back, we can help make recommendations on how to best use that water,” she said.

“Our recommendations will change based on levels of minerals and what minerals are elevated, but generally speaking, when the levels of sulphates, for example, are 2,000 parts per million or less, we can usually work with a mineral program to help compensate some of the deficiencies that those animals will experience from those sulphates, trace mineral deficiencies in particular. Once we get above that, we can start talking about… different times of year that would be best for breeding animals to use that water.”

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