The crude protein production of grassland and the utilization by milking cows.

An attempt was made with experimental data of various origins to quantify the intake of N from pasture grass by milking cows during the grazing period. It was also demonstrated how much of this N was removed by secretion in the milk as well as the conc. of N in the faeces and in the urine remaining on the pasture after grazing. From a fertilizer application to the pasture of 450 kg N/ha yr an equal conc. was taken up by the herbage. Of this herbage N about 75-80% remained on the pasture after grazing. The conc. remaining on the grassland increased sharply with increasing N rates and this went parallel with an increasing intensity in the N circulation in the system soil-plant-animal-soil and a rising NO3 content in the surface layer of ground water. (Abstract retrieved from CAB Abstracts by CABI’s permission