Managing Dugout Water Quality

REGINA - Jun 29/04 - SNS -- Cattle producers need to manage the quality of water in their dugouts to prevent it from becoming unpalatable to animals.

It’s only natural that dugout turbidity, or the amount of suspended solids in the water, increases with animal activity around and in dugouts. And, as a result of this animal impact, odor is likely present, along with algal growth, and cyanobacterial or blue-green algae growth. Taste will also be affected.

"It has been shown that water intake may be reduced significantly by a reduction in quality factors," says Bob Klemmer, Livestock Agrologist with Saskatchewan Agriculture, Food and Rural Revitalization in Weyburn. "And any reduction in water intake can lead to a corresponding reduction in feed intake, which, in turn, affects cattle performance in areas such as weight gain, milk production, and fertility. In fact, weight gain can be affected by as much as 0.3 pounds per day on grazing yearling cattle."

Poor water also raises animal health concerns such as enteric diseases and the potential for blue-green algae poisoning which can kill cattle, horses, sheep and dogs.

"Unrestricted direct access to dugouts means that cattle will tend to wade-out into the dugout before drinking. This brings them into daily contact with mud and the organisms responsible for foot rot, which are found in soil almost anywhere cattle activity takes place. Because of this close contact with mud and the likelihood of disease causing organisms, there’s an increased risk of foot rot," Klemmer said.

As for enteric diseases, cattle that enter a dugout to drink will also urinate and defecate in the water. This can lead to cross contamination within the herd if any animal using the dugout is infected with enteric disease causing organisms such as e-coli, giardia, or cryptosporidia.

Animal poisoning and death can be caused by a toxin that is released by cyanobacteria, commonly known as blue-green algae, when its bloom dies off. Algae growth can occur in a dugout after an influx of soil nutrients caused by run-off from snow melt or torrential rain. The combination of readily available nutrients and warm weather provides the optimum conditions for both algae and cyanobacteria growth.

There are several simple and some inexpensive solutions to the problem of water quality in dugouts.

"Anything producers can do to limit animal impact in and around the dugout will enhance water quality," Klemmer says. "Simply fencing the dugout and constructing a wood or gravel ramp to the water’s edge can restrict animal impact and control the severity of pollution concerns. Even more effective is pumping the water into troughs adjacent to the dugout. Where power is available, the operational cost is minimal. However, solar powered pumping systems using a storage tank and troughs have proved practical where power is not economically feasible. Troughs need not be fancy, and costs can be quite low using a few posts, rails and a plastic liner."

Another effective way of preventing nutrient pollution and silting of the dugout is to establish grass on any waterways leading to the dugout, Klemmer said. This is especially important where the dugout is situated in a saline area. If, over a period of years, grass or alfalfa can be established around the dugout and along the waterways leading to the dugout, the plant growth will reduce the amount of surface salinity. It does this by reducing water evaporation at the soil surface and encouraging the downward movement of water and salts through the action of precipitation.

One of the most effective ways to limit algae growth and encourage the development of a healthy microbial ecosystem within the dugout is aeration, Klemmer said.

"Given the size of most modern dugouts, the use of an electrical compressor is usually necessary to ensure enough air volume to do the job," Klemmer said. "Air volume and distribution are both important, as it is necessary to establish a turn-over of water from top to bottom in order to be fully effective. Here again, AC power or solar electric DC power are both equally effective."

As a last resort, the application of copper sulphate, or bluestone, can be effective in controlling algal and cyanobacterial blooms on the dugout surface. Klemmer says both the amount and distribution is very important in order to be fully effective. An estimate of water volume is required in order to determine the amount of copper sulphate necessary.

"Application methods can include dissolving the copper sulphate in water and spraying the solution evenly onto the surface; or spot spraying; or employing the old stand-by of dragging a burlap or nylon bag through the water using a grid-like pattern. Regardless which of these methods is used to kill off the bloom, be certain to keep animals, including dogs, away from the water for 14 days following treatment. This is necessary to prevent accidental poisoning," Klemmer said.