Matching animal demand to forage availability is a core principle in sustainable rangeland management. We evaluated the use of interannual flexibility in stocking rates compared with fixed stocking at light, moderate, and heavy stocking rates on livestock weight gains and economic responses for 7 yr (2016−2022) in North American northern mixed-grass prairie. The grazing season began in early June each year, so stocking rates in the flexible treatment were calculated on the basis of the amount of forage production predicted from actual precipitation received in April and May combined with long-term mean annual precipitation received at the study site in June, as well as an adjustment in stocking rate based on the amount of residual forage remaining at the end of the previous grazing season. Across years, mean stocking rate for the flexible stocking treatment (32.5 animal unit days [AUD] ha) was between heavy (38.6 AUD ha) and moderate (29.7 AUD ha) and was twice as high as the light (15.8 AUD ha). Cumulative total beef production for the 7 yr was highest with heavy stocking (282.6 kg ha), 17% less in the flexible (234.2 kg ha), and 19% less in the moderate (229.4 kg ha) stocking rates. It was 55% lower with light stocking (128.4 kg ha). Crude protein and digestible organic matter, as well as composition of plant functional groups in diets of yearlings, did not differ between the moderate versus the flexible stocking treatments. Compared with moderate stocking, flexible stocking resulted in 6.9% lower cumulative gross ($2 299) and 10.8% lower net ($1 407) economic returns per yearling. We suggest that future evaluations of flexible stocking strategies consider incorporating seasonal forecasts combined with intraseasonal adjustments in stocking rates as the growing season unfolds. Advancements in predictive forage forecasting tools and remote sensing capabilities are needed to support such a strategy.

中文翻译：

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灵活放养：混草草原的畜牧生产和经济反应

将动物需求与饲料供应相匹配是可持续牧场管理的核心原则。我们评估了北美北部混草草原 7 年（2016−2022 年）内放养率的年际灵活性与轻度、中度和重度放养率下的固定放养对牲畜体重增加和经济反应的影响。每年6月初开始放牧，因此灵活处理的载畜量是根据4、5月实际降水量预测的牧草产量，结合研究点长期平均年降水量计算的6月份的放牧量，以及根据上一放牧季节结束时剩余草料的数量调整载畜量。多年来，灵活放养处理的平均放养率（32.5 动物单位天[澳元]公顷）介于重度（38.6 澳元·公顷）和中度（29.7 澳元·公顷）之间，是轻度放养（15.8 澳元·公顷）的两倍。7 年的牛肉累计总产量在大量放养时最高（282.6 公斤公顷），在灵活放养时减少 17%（234.2 公斤公顷），在适度放养时减少 19%（229.4 公斤公顷）。少量放养（128.4 公斤/公顷）则降低了 55%。一岁鱼日粮中的粗蛋白和可消化有机物以及植物功能群的组成在适度放养与灵活放养处理之间没有差异。与适度放养相比，灵活放养导致每岁鱼的累计总毛额（2 299 美元）降低 6.9%，净经济回报（1 407 美元）降低 10.8%。我们建议，未来对灵活放养策略的评估考虑将季节性预测与生长季节展开时的放养率季内调整结合起来。需要先进的饲料预测工具和遥感能力来支持这一战略。