Phosphorus nutrition of beef cattle. 2. Relation of pasture phosphorus to phosphorus content of blood, hair and bone grazing steers

Abstract

The phosphorus content was measured every three months in pasture and in blood, hair and bone of beef steers that had grazed pastures of low phosphorus content for 12 months. This was done to determine the effect that changes in pasture phosphorus levels had on the phosphorus content of animal tissue. The correlation coefficients between pasture phosphorus content and either the phosphorus content of hair or the concentration of inorganic phosphorus in plasma were not significant. The relationship between the phosphorus content of pasture (x) and dry fat-free rib-bone (y) was given by the equation y = 9.5 + 33.3x (r = 0.97; P < 0.05). It was concluded that bone phosphorus content could provide the best estimate of the phosphorus status of grazing cattle because it significantly reflected variation in the phosphorus content of pasture whereas blood and hair failed to do so.