Context Modern crop stubbles provide an important source of feed for sheep during summer but can vary widely in their feeding value due to Genetics × Environment × Management interactions during crop growth, and how chaff is managed at harvest. Stubbles are difficult to assess for grazing value, due to the heterogeneity of forage components (e.g. stem, leaf, grains), which means that livestock producers rely on their observations and experience to manage sheep grazing stubbles. Aims To provide current information on the feeding value of stubbles, and to establish better methods for estimating stubble feeding value. Methods In the present paper, we report the results of sheep grazing wheat-stubble paddocks and a survey of the nutritive value of standing stubbles and chaff lines and piles of grain crops (including wheat, barley, canola and lupins) from crop paddocks in the mixed-farming region of Western Australia. Key results Without supplementation, wheat stubbles provided 50–100 dry sheep equivalent grazing days per hectare, before the estimated metabolisable energy (ME) intake of sheep fell below maintenance. This was influenced by ewe body condition score, where sheep of lower body condition gained more weight on stubbles (89 g/day higher weight gain per unit lower body condition score). Estimated ME content of edible chaff (leaf, fine stem and seed sheath or pod, excluding main stem and grain) was 5% higher in barley, 19% higher in lupin, and 5% lower in canola, than in wheat chaff, which was 5.9 MJ ME/kg DM. Implications While the grazing value of modern stubbles is variable, they have an important role in the seasonal feedbase by providing several months of feed during summer. Chaff by itself does not meet the energy or protein requirements of livestock, so a high-protein grain supplement (e.g. lupins) is necessary to maintain non-lactating ewes fed only chaff. The increased use of chaff lines and piles at harvest, primarily for weed control, provides a new opportunity to fill feed gaps in sheep and cattle enterprises if the material can be transported and stored efficiently, or if grazed in situ, as is common practice.

中文翻译：

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谷物作物的残茬和谷壳作为夏季羊饲料来源的价值

背景现代作物残茬在夏季为绵羊提供了重要的饲料来源，但由于作物生长过程中的遗传 × 环境 × 管理相互作用，以及收获时如何管理谷壳，它们的饲喂价值可能会有很大差异。由于草料成分（例如茎、叶、谷粒）的异质性，残茬难以评估放牧价值，这意味着畜牧生产者依靠他们的观察和经验来管理绵羊放牧残茬。目的 提供有关残茬饲喂价值的最新信息，并建立更好的估算残茬饲喂价值的方法。方法在本文中，我们报告了绵羊放牧麦茬围场的结果以及对立茬和谷壳线以及谷物作物（包括小麦、大麦、油菜籽和羽扇豆）来自西澳大利亚混合农业区的作物围场。主要结果 在没有补充的情况下，小麦茬每公顷提供了 50-100 天的干羊当量放牧天数，然后绵羊的估计代谢能 (ME) 摄入量低于维持水平。这受到母羊身体状况评分的影响，其中较低身体状况的绵羊在残茬上增加了更多的重量（每单位较低的身体状况评分增加了 89 克/天的体重）。估计食用谷壳（叶、细茎和种皮或豆荚，不包括主茎和籽粒）的 ME 含量在大麦中比小麦谷壳高 5%，羽扇豆高 19%，油菜籽低 5%。 5.9 MJ ME/kg DM。影响 虽然现代残茬的放牧价值是可变的，它们在夏季提供几个月的饲料，在季节性饲料库中发挥着重要作用。糠秕本身不能满足牲畜对能量或蛋白质的需求，因此需要高蛋白谷物补充剂（例如羽扇豆）以维持仅饲喂糠秕的非泌乳母羊。在收获时更多地使用谷壳线和草堆，主要是为了控制杂草，如果材料可以有效运输和储存，或者如果按照惯例就地放牧，则为填补羊和牛企业的饲料缺口提供了新的机会。