The use of faecal analyses to estimate the phosphorus intake by grazing sheep. II. The repeatability of the technique and the influence of varying the phosphorus intake

Abstract

Analyses of rectal faeces of sheep for phosphorus, calcium and magnesium may be useful to indicate the mineral status of the herbage being consumed. A number of sheep should be used for each pasture, but this would entail a large number of individual analyses. In this experiment it was shown that a pool analysis of faeces did not differ significantly (P < 0,01) from the arithmetic mean of the individual samples (20). In 13 replications this was true for phosphorus, calcium and magnesium, whether the sheep were non-pregnant, non-lactating, pregnant, or lactating. From the results it was estimated that 3 faecal pellets from at least 30 sheep should be used to make the pool. Blood was also taken on 11 occasions for pool and individual (20) analyses. No significant difference was found for plasma inorganic phosphate, magnesium and total protein, but on 3 occasions there was a significant difference (P< 0,01) for plasma calcium.