By Dr. Walter Willms and Dr. Doug Colwell, Agriculture and Agri-Food Canada and Orin Kenzie, Alberta Agriculture, Food and Rural Development
Field trials at the Agriculture and Agri-Food Canada Range Substation near Stavely, Alberta, have shown that the source of drinking water for livestock has a major effect on animal performance. Most water quality concerns have focused on salts or toxic blue-green algae, but our trials have shown that other factors, which are mostly unknown, may be equally important for the profitability of a ranch and the well-being of livestock.The trials compared two water sources: fresh water delivered to a trough and water in a dugout. The fresh water came from a well in one trial and from a flowing creek in the other. The dugouts were about 43 years old, at least two meters deep, and recharged from surface runoff. Twelve cow-calf pairs on rough fescue pasture in good condition were monitored.
Over a 33-day period to the end of September, cows drinking from the dugout lost 0.2 kg and their calves gained 26.3 kg. On the other hand, cows drinking from the trough gained 7.4 kg and their calves gained 33.9 kg.
A similar study in 1990 and 1991 used steers and found that over the course of 71 days, 18-month old steers gained 1.21 kg/day drinking fresh water and 0.93 kg/day when drinking from the dugout. This translates to a 23 per cent reduction in weight gain.
Water quality analyses did not show any reason for the differences in animal performance. Total dissolved solids, sodium, bicarbonates, and other chemical constituents were not excessive for livestock and were slightly lower in the dugout water, indicating that salts were not responsible for the effect. Algal growth was scarce and the blue-green species were absent during the trials. Therefore, other unidentified factors affected the performance of animals drinking from the dugout.
The immense difference in weight gains warrants further research to pinpoint the cause and find whether simply pumping water into a trough is a solution. We are developing research projects to answer the many questions posed by these trials. The lower weight gains associated with dugouts could be caused by harmful organisms in the water. Another possible factor is the reduced palatability of dugout water caused by organisms or the release of methane, ammonium, or hydrogen sulfide from the muck disturbed by the animal. Reduced water intake can result in lower forage consumption and, consequently, reduced weight gains.
In range management, water quality has been largely ignored, except when salts and toxic algae are a concern, or when livestock can damage riparian sites. It appears that the water source must be given much greater consideration to make better use of range resources and improve the profitability of livestock grazing.