The Effects of Water Quality on Cattle Weight Gain : Summary of Results of Study Years 1999 - 2002

A collaborative study conducted by Agriculture and Agri-Food Canada and the Western Beef Development Centre.

Summary

Dugouts are a common means of storing water for range cattle on the Canadian prairies. Variability in the quality of dugout water raises questions about the possible impacts on animal health and productivity. A four year study was undertaken to evaluate the effects of remote watering, aeration and coagulation of livestock drinking water, and to identify causal factors affecting livestock water intake. There were four treatments in the study: 1) direct access to a dugout; 2) dugout water pumped to a trough 3) aerated dugout water pumped to a trough; 4) coagulated and chlorinated dugout water pumped to a trough representing an increased level of treatment. Eleven (11) steers were allocated to each treatment. The steers in each treatment were in a rotational grazing system and had access to only one type of water. Water intake (except direct access), water quality, forage production and quality; parasites, and livestock weight gains were monitored.

The following water quality parameters: E. coli, iron, manganese, chlorophyll a, color, turbidity and ammonia all decreased with increasing level of treatment. Dissolved organic carbon, total phosphorous, and odour, were lower in the coagulated treatment than the other three treatments.

Water treatment affected (P<0.10) weight gains by steers in the early summer but not (P>0.10) in late summer. Although the only statistically significant weight gain improvement was a 0.09 kg/day improvement in weight gain of the aerated treatment versus the direct entry, there was a tendency for improved weight gain with a ranking of direct access < pumped < coagulated < aerated. Water consumption was higher for coagulated and aerated treatments than the pumped treatment. The quantity of water consumed per unit of weight gain increased as the season progressed, presumably, as the forage became senescent and average air temperature increases. Steers drinking direct access water spent less time grazing and more time resting than the steers in the other treatments. Drinking frequency was similar among treatments (P>0.10), but steers spent more actual time ingesting water in the direct access, coagulated, and aerated treatments than the pumped. This may be linked to the fact that animals may reduce their intake due to palatability factors.

Water consumption showed consistent trends in 1999 and 2000, with consumption highest for coagulated water. In 2001 and 2002 the results were inconsistent. In 1999, the variation in seasonal weight gain closely matched the variation in seasonal water consumption.

The variable animal weight response to water treatment is open to speculation and further investigation. It seems reasonable to assume that in the drought of 2000 and 2001, the reduced forage quality and quantity may have been a limiting nutrient and obscured any benefit of improved water quality. There is no doubt that live weight gain is the end result of a treatment response produced by animal behavior, physiological reaction and, possibly, livestock management. There is a trend developing with the steers showing an increase in weight gains with an increase in water quality.

Inexpensive treatments of dugouts can reduce levels of taste, odour, and animal health related constituents. Water quality impacts both water intake and weight gains. The aerated treatment demonstrated a significant increase in water intake and weight gains. Thus aeration can be an economical method to improve water quality, livestock production, and dugout longevity.