EFFECT OF FERTILISER AND SUPPLEMENTARY PHOSPHORUS ON THE INTAKE AND DIGESTIBILITY OF THE LEGUME Desmodium introtum

The application of fertilizer P to Desmodium intortum at 40, 60 and 100 kg/ha resulted in the P content of the legume regrowth being 0.10, 0.13 and 0.16% on a dry matter basis. When the forages were fed alone to sheep in metabolism pens the corresponding voluntary intakes by sheep of the three forages were 27.3, 42.7 and $54.3g/W_{kg}{^{0.75}}$, respectively. Provision of additional P by rapid infusion into the rumen each morning before any fresh food was offered depressed the voluntary intake of all three feeds. It is suggested that the adverse effect of supplementary P was probably caused by an induced deficiency of either Ca or Mg and led to a reduction in microbial activity in the rumen.