Livestock Water Quality

A number of factors affect the quality of surface water sources. Nutrient loading from spring or summer run-off, little to no re-charge from a dry spring/summer, animal impact from direct cattle watering, and sub-surface soil or water salinity are but a few of the possibilities.

Many dugouts located in saline areas may be fed from the bottom with saline ground water. These dugouts may also be fed by spring run-off, which can impact both quantity and quality of the water. The water in these dugouts may have naturally high mineral levels to start with and, without fresh water recharge (as well as summer evaporation causing mineral concentration), producers may find the mineral content in the water elevates to levels that are not suitable for use by fall. The only way to determine the mineral content of these water sources is to have water tests done by a lab.

Tables 1 and 2 provide levels of some parameters and consequent effects on livestock.

Table 1.Total Dissolved Solids interpretation chart for livestock use

Total Dissolved Solids (TDS) Water content (mg/L or ppm)	Usefulness for cattle, sheep, or horses
<1000 - 3000	Acceptable
3,000-5,000*	Generally Acceptable; Requires further mineral analysis May cause diarrhea May reduce performance, reduce growth and affect health of ruminants
5,000-7,000	Poor Likely to cause diarrhea Avoid use for pregnant and/or lactating cows Test for sulphates Reduced animal performance
7,000-10,000	Potentially unsuitable – unfit for young, pregnant or lactating cattle Sulphates likely high Negative effects in all animal classes Further mineral analysis required
>10,000	Unsuitable

Table 2. Sulphate interpretation chart for livestock use

Sulphates (SO₄) Measured as SO₄ Water content (mg/L or ppm)
<500	Good
500-1,000	Good Diarrhea or refusal of water by animals not accustomed to it 500 to 800 mg/L may affect calves, inducing a trace mineral deficiency Trace mineral deficiencies can cause depressed growth rate, depressed fertility and depressed immune response Decreased performance in feedlot cattle 1,000 mg/L recommended maximum if feed level is high in sulphates or if ambient temperature is high
1,000-1,500	Acceptable Laxative Performance reduced High levels of sulphates can also contribute to copper and other trace mineral deficiencies
1,500-2,000	Poor Chelated or Hydroxy minerals may be required High chance of trace mineral deficiency Symptoms include: decreased gains, depressed immunity and reduced conception, etc. Sporadic cases of polio possible 2,000 mg/L> can cause diarrhea and reduced milk production in dairy cows
>2,000	Unsuitable Sporadic cases of polio are highly probable Performance reduced Scours likely Greater than 4,000 mg/L dangerous health problems expected

In general, the tolerance of animals to sulphates in water depends on total dietary intake of sulphate and will depend on the levels in feed and total water consumption. Total water consumption will be influenced by environmental temperatures, moisture levels in feed and stage of production. There is also the opportunity for cattle to become accustomed to sulphates, as rumen microflora can slowly shift over time. It is recommended that this tolerance not be relied upon when making management decisions.

Elevated water sulphates have been shown to also negatively impact growth and performance of cattle. A trial done by Loneragan et al. (2001) fed backgrounding cattle water with varying amounts of sulphates. When introduced to a water source containing varying levels of sulphates, cattle fed water approaching 2,000 mg/L sulphates gained 19 per cent less weight (0.9 lbs/day less) during the first 28 days on that water source compared to cattle introduced to water that had only 200 mg/L sulphates.

Lab testing is the single best way to test for dissolved minerals including sulphates, conductivity and Total Dissolved Solids (TDS). Handheld conductivity meters have been increasing in popularity and can be a useful screening tool when working properly. Field testing in 2017 by Livestock and Feed Extension Specialists demonstrated the following considerations when using handheld meters:

Meters must be tested against lab results to maintain accuracy;
Meters/probes have lifespans and should be replaced according to manufacturer specifications; and
Conversion factors used to calculate TDS from conductivity can be misleading. Commonly these meters are calibrated to estimate TDS at 67 per cent of conductivity when 2017 testing (n=555) demonstrated TDS was on average 89 per cent of conductivity.

Water Consumption Requirements and Sources

If trucking or piping water becomes a necessity, the following are some guidelines for drinking water requirements for various sizes of animals. These will be useful when trying to determine the size of water storage required. Keep in mind that water requirements increase at higher temperatures.

Cows: 67.5 L (15 gallons) for nursing cows; 54 L (12 gallons) for bred dry cows and heifers.
Bulls: 54 L (12 gallons).
Growing cattle: 45 L (8 gallons) for 400 lb. animal; 45 L (10 gallons) for 600 lb.; 54 L (12 gallons) for 800 lb.
Finishing cattle: 85.5 L (19 gallons) for 400 to 1,200 lb. animal.

Keeping stock physically out of the water source will increase the water available, as well as increase the quality of the water. There are a number of ways to accomplish this, but no perfect system fits all situations. Some viable options may include:

Access Ramps	Improves access and preserves slopes on water site and will limit nutrients entering from manure and urine. Some improvement in quality is likely to occur.
Nose Pumps	Animals will need to learn how to use this system. Need one pump for every 25 to 30 animals. May need more than are recommended by the manufacturer.
Gravity Flow Reservoirs	Requires some excavation to build. Not suited to all sites, as water must flow downhill from water source to trough.
Solar Pumping Stations	Works in remote locations. Requires storage batteries and water storage.
Windmills	Works in remote locations and requires little maintenance. High variability in winds means that water storage is necessary.

Every individual watering site may have characteristics that make it more suitable to one system than another. As a result, consultation with a Livestock and Feed Extension Specialists is a good idea prior to developing alternative systems. These systems will have benefits in subsequent years through better quality water and longer watering site lifespan.

Summary

If you encounter poor quality water, the following options may be considered:

Switch to a source of better quality water, or use the better quality water to dilute the minerals in the poor water; you must be aware of the quality of both sites;
If your herd is large enough, it may be less costly (per cow per year) in the long run to look into installation of a water treatment system;
Depending on the mineral levels, make use of poorer quality water at certain parts of the year or with certain classes of animals that are less affected; and
Make use of the Farm and Ranch Water Infrastructure Program to help with pasture pipelines, new water infrastructure (wells or dugouts) or through expanding an existing dugout of known good water quality.

Staff in the Ministry of Agriculture Regional Offices can assist with interpretation of water test results and provide information on management and program funding options.