Livestock animals play a key role in organic farming systems by providing nutrients for croplands through manure production and nutrient-dense food for human consumption. However, we lack global, synthetic view about livestock productivity in organic farming and about its differences with conventional farming. Here we fill this important gap of knowledge by providing a first global comparison highlighting differences between organic and conventional farming on animal productivity, feeding strategy and feed use efficiency in dairy cattle, pigs and poultry (both layers and broilers). We found (a) a 12% lower animal productivity under organic treatment, (b) significant differences in feeding strategy, especially for organic dairy cattle fed with a lower proportion of concentrate and food-competing feed than in conventional systems, (c) an overall 14% lower feed-use efficiency under organic treatment (−11% and −47% for organic dairy cattle and poultry broilers, respectively) compensated by (d) a 46% lower human-food vs animal-feed competition in organic dairy cattle. These results provide critical information on the sustainability of organic livestock management. They are also key for modelling global organic farming expansion while avoiding overestimation of organic farming production in upscaling scenarios.

牲畜通过有机肥料的生产为农田提供营养，并为人类消费提供营养丰富的食物，从而在有机耕作系统中发挥关键作用。但是，对于有机农业中的牲畜生产率及其与常规农业的差异，我们缺乏全球综合的看法。在这里，我们通过提供首次全球比较来填补这一重要的知识空白，重点是有机耕作和常规耕作在奶牛，猪和家禽（包括蛋鸡和肉鸡）的动物生产力，饲喂策略和饲料使用效率之间的差异。我们发现（a）经过有机处理的动物生产率降低了12％，（b）喂养策略存在显着差异，尤其是对于有机和浓缩饲料和食品竞争性饲料所占比例低于传统系统的有机奶牛，（c）在有机处理下，整体的饲料使用效率降低了14％（有机奶牛和家禽肉鸡分别降低了-11％和−47％），而（d）人类食品与动物饲料的竞争降低了46％在有机奶牛中。这些结果提供了有关有机牲畜管理可持续性的重要信息。它们也是建模全球有机农业扩张的关键，同时避免了在规模扩大的情况下高估有机农业产量的情况。