The health and performance of the grazing animal in relation to fertilizer nitrogen usage. II. Weaned lambs

Abstract

1. Experiments were carried out in 1961 and 1962 to study the effect of high levels of nitrogenous fertilizer on the health and performance of early weaned lambs. The lambs were artificially reared and grazed in a ‘worm-free’ area. In 1961, levels of Nitro-chalk were applied at 22 and 110 kg. N/hectare/month and in 1962 an intermediate level of 66 kg. N/hectare/month was added; the actual totals applied per hectare were 220,660 and 1100 kg. to treatments N1, N2 and N3 respectively. All nitrogen treatments were carried out with and without irrigation (applied to maintain a soil moisture deficit of less than 2.5 cm.).2. Lambs were introduced to the experimental plots when 8-10 weeks of age and grazed in rotation a series of four paddocks on each treatment; a low grazing pressure was maintained at all times.