Watch for Sulphates and Blue-Green Algae in Cattle Water Supplies

Some livestock producers are still feeling the effects of consecutive years of drought on the Prairies.

Over the past few years, cattle producers have been forced to haul water from nearby wells when creeks ran dry and the remaining potholes turned salty. Some producers lost cattle from complications associated with sulphur toxicity.

In some cases, water analysis of potholes in creeks indicated sulphate levels in excess of 5000 mg/L - higher than the recommended maximum of 1000 mg/L. Health effects such as scours may be seen in calves drinking water with only 500 mg/L of sulphate, but at this concentration they will usually adapt over time with few health problems.

To prevent sulphur toxicity, producers should also be aware of the sulphur content of feed sources, as well as their water supply. High sulphate feed, coupled with higher concentrations of sulphate in water, can cause problems.

Increased sulphate levels can cause deficiencies in trace minerals which can contribute to a depressed growth rate and infertility in the herd. The most serious is thiamine deficiency, which can result in nutritional polio B a disorder which can cause loss of co-ordination and blindness. Other signs of sulphate toxicity are Ahead pressing@ (animals pushing their heads into a solid wall), star-gazing and convulsions. Early treatment with intravenous thiamine, reduced sulphate content in feed sources and improved water quality can rapidly improve the health of the animal.

Total dissolved solids (TDS) is a measure of all salts, including sulphates. If TDS levels exceed 3000 mg/L, additional testing and close monitoring of the water are advised. TDS tests are inexpensive and can be performed by most labs. Removal of these materials can be challenging and costly and is not often pursued. This usually means finding another water source.

Cyanobacteria (blue-green algae) can also appear in dugout water supplies during prolonged dry spells due to increased concentrations of nutrients. Some varieties of blue-green algae can produce liver or brain toxins. A rapid release of toxins may occur when the cyanobacteria die from lack of nutrients, or from the application of an algaecide such as copper sulphate.

Keeping cattle out of the dugout, minimizing inflow of nutrients and using floating intakes will help minimize potential problems with toxins. Aeration will also reduce algae growth by decreasing the resuspension of nutrients which occurs when oxygen is depleted in the bottom of the dugout.

Remote watering will also reduce the level of bacteria, viruses and parasites entering the water. These organisms can cause numerous diseases and health problems which can lead to production losses. Concentrations of these organisms tend to increase under dry conditions, exposing cattle to greater health risks.

In dry years, many producers search for alternative water supplies, such as wells, sloughs or groundwater fed dugouts to supplement their supply. However, these sources may be high in salts, and should be tested before using.

Testing of water is always important, but more so during dry periods or when health problems are observed in the livestock. Many labs now test for algae toxins or algae species that produce toxins.

For more information on managing through drought conditions, contact your nearest Agriculture and Agri-Food Canada – PFRA office.