The effect of high concentrations of the mineral components of coal mine pH water on productivity of steers

Abstract

Proc. Aust. Soc. Anim. Prod. 1996 Vol. 21 THE EFFECT OF HIGH CONCENTRATIONS OF THE MINERAL COMPONENTS OF COALMINE PIT WATER ON PRODUCTIVITY OF STEERS T.J. KING, G.S. HARPER and R.A. HUNTER Tropical Beef Centre, CSIRO Division of Tropical Animal Production, Rockhampton, Qld 4702. In a number of locations in Australia open-cut coal mining and beef production exist side by side. Water that accumulates in coal mine pits usually has a high mineral content from salts leached from surrounding parent material. This water is a potential source of drinking water for cattle, especially during drought. The current guidelines for tolerances of cattle to mineral contamination of drinking water have been based on field observations and not from rigorous experimentation (ANZECC 1992). This paper summarizes 5 experiments designed to determine the effect of the major individual constituents of coalmine pit water on health and productivity of beef cattle. Brahman crossbred steers were housed in individual pens in a roofed animal house and fed long-chopped hay ad libitum. There were 5 steers per treatment group. Treatments were usually 500, 1000 and 2000 ppm sulphate with town water (30 ppm sulphate) as control. In other experiments, treatments were 500, 1000 and 2000 ppm chloride, and 500,lOOO and 1500 ppm magnesium as a 1: 1 mixture of MgSO, and MgCl,. Animals were adapted to high concentrations of salts by increasing concentration by 500 ppm each 7 days until final concentration was reached. The duration of the experimental period at final concentration was at least 6 weeks. The results from the highest concentration groups of the 5 experiments are summarized in Table 1. These data, together with those of King and Hunter (1994), showed that in steers fed medium quality luceme (Medicago sativa) hay or low quality Angleton grass (Dicanthum aristatum) hay, feed intake, water intake, and growth rate were not significantly (P>O.O5) affected by concentrations of coalmine pit water, Na,SO,, MgSO, or CaCk up to 2000 ppm sulphate or chloride. Similarly, there was no significant effect of magnesium up to 1000 ppm (2000 ppm sulphate). Further, there were no visible signs of ill-health or any indication of dehydration, determined as body water content by urea dilution methods. Table 1 The effect of five salt treatments on water intake, dry matter intake and growth rate The guidelines for ppm for sulphate and tolerate at least twice productivity. We wish to thank maximum concentration of minerals in drinking water for livestock recommend 1000 400 ppm for Mg (ANZECC 1992). The results of this study suggest that steers can these concentrations when introduced over an extended time, without compromising BHP Coal Australia for their support. ANZECC (1992). In 'Australian Water Quality Guidelines for Fresh and Marine Waters' (Australian and New Zealand Environment and Conservation Council), ~~-5-21. KING, T.J. and HUNTER, R.A. (1994) Proc. Amt. Sot. Animal Prod 20: 341. 450