Water quality guidelines for livestock watering in Southern Africa

The validity of the water quality guidelines for livestock watering is questionable as these are based largely on international guidelines and lack locally established water quality constituent lists, levels of acceptability and reference to Southern African livestock production systems. The water quality constituents fluoride chloride, total dissolved solids and sulphate were identified in a review of subterranean water samples for non-hydrogauging stations from the Northern Province, North-Western Province and the Northern Cap Province as being the primary constituents of concern for livestock watering. Biological trials-investigating toxicological and palatability aspects regarding the constituents fluoride, chloride, total dissolved solid, sulphate, nitrate and nitrite were conducted in sheep, cattle and poultry. The results indicated that the guidelines in use were too conservative for specific categories of livestock within Southern African livestock production systems, and that the guideline format used was inadequate in assessing the effects of water quality over the diverse range of livestock production systems found in Southern Africa. For a more accurate assessment of the effects of water quality for a given livestock production system the format should be based on ingestion levels, as opposed to a mg/l basis, and should take into account site-specific synergistic and antagonistic interactions within and external to the water to a greater extent. The results led to the compilation of the interim water quality guidelines currently in use and to the formulation of a water quality guideline index system.