This study determined the impact of a change in grazing system on beef production from lucerne pastures in Argentina. One system (T500) used the traditional recommendation to commence grazing in spring when lucerne was near to 10% flowering. The grazing interval was ~ 500 growing degree‐days (GDD; above a base temperature for growth of 5°C) from mid‐spring to mid‐autumn. In contrast, the T350 system commenced grazing 11–15 days earlier at ~ 1,000 kg DM/ha and the grazing interval was ~ 350 GDD from mid‐spring to mid‐summer, and from mid‐summer to mid‐autumn, it was ~ 500 GDD. Total live‐weight production was ~ 30% or 185 and 115 kg/ha higher in T350 than T500 in Years 1 and 2 respectively. This was due to a higher live‐weight production per head and a higher stocking rate, because T350 produced 1,600 kg DM ha⁻¹ year⁻¹ more forage. Plant population (~70 plants/m²) and perennial biomass (root plus crown) at the end of the second year did not differ between treatments. This suggests that lucerne persistence was not affected by the more intensive spring grazing of T350, because an adequate period of autumn recovery was allowed. This work quantified the live‐weight gain (+30%, +150 kg/ha) when the grazing management of lucerne during the spring–summer period was based on crop growth status (i.e. standing biomass, canopy height) rather than on crop phenology.

中文翻译：

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温带气候下不同放牧条件下卢塞恩（Medicago sativa L.）草场的动物和草料响应

这项研究确定了放牧系统变化对阿根廷卢塞恩牧场的牛肉生产的影响。一种系统（T500）使用传统的推荐方法，于春季在卢塞恩开花接近10％时开始放牧。从春季到秋季，放牧间隔约为500个生长日（GDD；高于5°C的生长基本温度）。相比之下，T350系统在11至15天前以〜1,000 kg DM / ha开始放牧，放牧间隔是从仲夏至仲夏〜350 GDD，从仲夏至中秋〜 500 GDD。在第1年和第2年，T350的总活重产量约为30％，即分别比T500高185和115 kg / ha。这是因为人均活重产量和放养率较高，因为T350的产量为1,600 kg DM ha ^-1 - ^1年增加草料。在第二年末，不同处理之间的植物种群（〜70株/ m ²）和多年生生物量（根加冠）没有差异。这表明，由于允许足够的秋季恢复期，T350春季放牧强度不会影响卢塞恩的持久性。这项工作量化了春夏期间卢塞恩的放牧管理是基于作物生长状况（即站立的生物量，冠层高度）而不是基于作物物候的动态体重增加（+30％，+ 150 kg / ha）。