The production of fattening cattle and extension of autumn grazing following three rates of application of nitrogenous fertilizer to a rye-grass/white clover sward

Publisher Website
Google Scholar
Abstract
1. Three levels of a nitrogenous fertilizer, supplying 0,104 and 208 lb. N per acre were applied in 1955 and 1956 to a rye-grass/white clover sward in its fourth and fifth harvest years on a loam soil overlying chalk.2. Levels of animal production were measured using fattening cattle maintained on the plots at a stocking rate of 1⅓ per acre: excess herbage was conserved and fed back to them later.3. Low rainfall in 1955 seriously affected yields of herbage and response to fertilizer, and severely reduced the clover content in all treatments.4. Rate of live-weight gain per head was not reduced by the application of fertilizer at either level. Vigour of the sward was maintained by fertilizer application in a dry spring period in 1956, whereas, in the control treatment, which was low in clover, gains per head were markedly reduced because of inadequate dry-matter production.5. By applying two-thirds of the fertilizer in late summer, a considerable extension of grazing time was obtained, particularly when rainfall was adequate. At the highest level of fertilizer application in 1956 the grazing season was extended from 6 months to 7½, and the cattle continued on conserved feed to a total of 8½ months. Response to the medium and high levels of application on grazed herbage only was 12 and 15 bullock-days per acre, respectively, in 1955. In 1956 the response was 46, and 67/59 (the two high nitrogen treatments). In terms of total live-weight gain per acre the response in 1955 to medium and high levels was 23 and 32% above control, up to 427 lb. per acre: in 1956 it rose to 51 and 52/55% with the highest treatment reaching 657 lb. per acre. Greater financial returns than are indicated by live-weight gain should result from the rising price per pound of carcass as the supply of fresh beef dwindles in early winter.6. Carcass data indicated that both greater rate of gain and the extra time spent on fertilized herbage and conserved feed increased carcass weight and maturity in the normal pattern of development, fat most rapidly, muscle next and bone least. No significant differences in conformation due to treatment was detected by analysis of grouped joints.