Consumption of pluronics administered in drinking water and roller drums to grazing beef cattle

Abstract

Variability between grazing beef cattle in pluronic consumption from a roller drum was estimated on three occasions using tritiated water as a marker, and was ¦ 58, ¦ 66 and ¦ 77 per cent when expressed as a coefficient of variation. Corresponding values when pluronic was given as a discrete dose in drinking water were ¦ 53, ¦ 67 and ¦ 38 per cent; these values are increased when the number of troughfulls consumed daily increases and when inadequate mixing of water and pluronic occurs whiie the trough is refilling. Daily water consumption averaged 20.8 litres day-1 animal-1 and was not affected by the inclusion of pluronic in the water but was increased when animals had access to roller drums containing molasses. Diurnal variability in ruminal pluronic concentration was monitored using 51Cr-EDTA as a marker. Variability was large with both methods of pluronic administration, and was related to drinking behaviour. Estimates of the half-life of the pluronic in the rumen were obtained, and were used to predict diurnal variability in ruminal pluronic concentration for varying frequencies, intensities and intervals of pluronic consumption.