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In temperate regions of New South Wales, Australia, there is increasing evidence of pasture decline, especially of deep-rooted, perennial pastures. Due to the high costs of farm inputs and of re-establishing pastures, grazing management has recently been investigated as a useful management tool to maintain production levels over the long-term - for the benefit of both pasture and animal. There is however inadequate knowledge of how to use grazing management to match the nutritional requirements of grazing animals with a variable pasture supply. This study was conducted at the CSIRO's Chiswick property, Armidale as part of the Cicerone Project - a producer-led research and adoption group which commenced a whole farmlet study of grazing enterprises in July 2000. The overall aim of the farmlet study was to assess the relative sustainability and profitability of three farmlet systems varying in farm inputs and grazing management. The main purpose of the study reported in this thesis was to examine the balance between both supply of feed (mostly from pastures) and the demand for feed by the range of livestock able to be supported by each farmlet. The data collected allowed the calculation of a 'partial' metabolisable energy balance (the estimate of a 'partial' balance was based on pasture growth and supplements and animal requirements without taking into account utilisation of the standing herbage mass, due to insufficient measurement of intake) as a means of comparing the relative match between supply and demand over time on each farmlet. The two primary hypotheses tested in this thesis related to the effects of two different farm management strategies (high inputs or intensive rotational grazing) to provide superior pasture and/or animal outcomes compared to a moderate-input, flexible grazing system which is typical of the region. The three farmlet systems, each of 50 ha, were farmlet A (high input system), farmlet B (typical district practice) and farmlet C (intensive rotational grazing). The control treatment, Farmlet B, represented the most common grazing system employed by graziers on the Northern Tablelands of New South Wales. The farmlets differed both in the level of inputs applied (pasture and fertiliser) as well as the system of grazing management employed. |
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