The influence of the grazing animal on the composition and productivity of the pasture sward has been a major subject for investigation by Grasslands Division over the past 10 to 12 years (l), (2), (3). In particular we have been interested in the effect of dung and urine on pasture growth, and at previous conferences of this association (4) papers have been presented to show that the quantities of plant nutrients returned to high-producing pastures are . equivalent in nitrogen to over a ton of sulphate of ammonia per acre per year, in phosphorus to over 6cwt. of superphosphate, and in potash to nearly a ton of 30 per cent. potash salts.