Comparison of stocking methods for beef production in northern Australia: seasonal diet quality and composition

Abstract

Managing and measuring the grazing and nutrition of cattle are required to improve the productivity and profitability of beef businesses in northern Australia. The quality and composition of the diet selected by cattle grazing in three stocking methods (continuous, extensive rotation and intensive (cell) rotation) on nine commercial properties in Queensland were estimated using near infrared reflectance spectroscopy analyses of fresh faeces; 585 faecal samples were analysed between 2005 and 2009. Sites were in two regions (north and south Queensland) and on two vegetation communities, namely brigalow (Acacia harpophylla F. Muell. ex Benth.) on clay soils and eucalypts on light-textured soil types. Pastures were dominated by perennial sown exotic grass species, predominantly Cenchrus ciliaris L. (buffel grass) at five sites and Urochloa mosambicensis (Hack.) (Sabi grass) at one site, and by native perennial tussock grasses at three sites. Seasonal profiles of dietary crude protein, dry matter digestibility, faecal nitrogen concentration, proportion of non-grass, ratio of crude protein to digestibility and an estimate of liveweight gain are presented for each stocking method. Overall, dietary crude protein, digestibility, faecal nitrogen, the crude protein : digestibility ratio and liveweight gain were significantly higher for animals grazed continuously, with short rest periods, than for animals in extensive or intensive rotations. There was a significant interaction between stocking method and pasture growing conditions, measured as a simulated growth index, for dietary crude protein and faecal nitrogen. There was no difference between stocking methods during periods when the index was <0.2, indicating no pasture growth, but during periods of active growth (index >0.5), crude protein and faecal nitrogen were higher with continuous grazing than in the extensive and intensive rotations. For cattle producers considering alternative stocking methods, the results suggest they can obtain similar ecological responses under any of the three methods and diet quality will be higher during the pasture growing period in continuously grazed pastures.

Research, development and adoption for the north Australian beef cattle breeding industry: an analysis of needs and gaps

“…For example, 30 years ago, O'Reagain and Turner (1992) concluded that there was little difference between continuous and rotational grazing systems in terms of effects on rangeland condition or animal production in South Africa. More recent Australian studies have supported this conclusion (Hunt et al 2013;Hall et al 2014Hall et al , 2016Schatz 2019), as have comprehensive reviews of the international literature (Briske et al 2008;Hawkins 2016). Therefore, it is not surprising that cell grazing was found to be much less profitable than set stocking because of its additional capital and operational costs, including the opportunity cost of labour (Hunt et al 2013).…”

Diet quality, liveweight change and responses to N supplements by cattle grazing

“…Nongrass species (forbs and browse) are present in many other seasonally dry native pasture rangelands both in northern Australia (Siebert et al 1968;Newman 1969;Hall 1981;Squires and Siebert 1983) and elsewhere such as tropical western Africa (Innes and Mabey 1964;Fianu 1982), and often make an important contribution to dry-season diet quality. However, these non-grass forages typically comprise only 50-150 g/kg of the diet during the dry season in the northern and southern speargrass, Aristida-Bothriochloa and semi-arid pasture systems (Squires and Siebert 1983;Coates and Dixon 2007;Dixon et al 2007bDixon et al , 2011Hall et al 2016). Moreover, because many browse species contain antinutritional factors (e.g.…”

Adaptive multi-paddock grazing management reduces diet quality of yearling cattle in shortgrass steppe

“…First, animals grazing at increased stock density may forage less selectively and have reduced diet quality because of greater intra-herd competition and the faster rate at which forage available is depleted (e.g. McCollum and Gillen 1998;Hall et al 2016). Second, long rest periods may allow maturation of forage in paddocks prior to the time that it is grazed (Denny et al 1977).…”