The increasing human population and demand for animal food products raise the issue of impacts of animal systems on food security caused by their use of human-edible feed and/or tillable land. The utility of replacing animal systems with potential food-crop systems needs to be assessed but is associated with many uncertainties. Some metrics analyse the contribution of current animal systems to food security, especially the dimension of food availability. These methods address feed conversion efficiency (i.e. total (‘gross’) or human-edible (‘net’)) or the efficiency of agricultural land use (i.e. total, permanent grassland, and tillable land) but never both simultaneously. The purpose of this study was to develop a new metric—‘net productivity’—to represent the performances of current animal systems more accurately by considering both the use of human-edible feed and agricultural land. Through a protein assessment, we analysed the ability of the existing and the new metrics to assess the performances of 111 dairy farms in Wallonia (Belgium). We found that net productivity was positively correlated with both metrics of feed conversion efficiency and negatively correlated with the three metrics of land use. To analyse the influence of farm characteristics, we grouped the farms into four clusters using k-means clustering based on these metrics of contribution to food security and then performed redundancy analysis to select the most influential farm characteristics aiming to highlight contrasted farm strategies. The highest net productivity was reached by an ‘intensive and net efficient’ farm strategy, which had intensive grass-based management, high milk production per cow, appropriate use of concentrates, and well-managed dairy followers (i.e. replacement heifers and calves). The newly developed metric of net productivity can be useful to quantify the contribution of dairy systems to food security by considering both the use of human-edible protein and agricultural land simultaneously.

不断增长的人口和对动物食品的需求提出了动物系统因使用人类食用饲料和/或可耕地而对粮食安全产生影响的问题。用潜在的粮食作物系统替代动物系统的效用需要评估，但存在许多不确定性。一些指标分析了当前动物系统对粮食安全的贡献，特别是粮食供应的维度。这些方法涉及饲料转化效率（即总的（“总”）或人类可食用的（“净”））或农业土地利用效率（即总的、永久草地和可耕地），但不能同时解决这两个问题。这项研究的目的是开发一种新的衡量标准——“净生产力”——通过考虑人类食用饲料和农业用地的使用来更准确地代表当前动物系统的表现。通过蛋白质评估，我们分析了现有指标和新指标的能力，以评估瓦隆（比利时）111 个奶牛场的绩效。我们发现，净生产力与饲料转化效率的两个指标呈正相关，与土地利用的三个指标呈负相关。为了分析农场特征的影响，我们使用以下方法将农场分为四个集群：我们发现，净生产力与饲料转化效率的两个指标呈正相关，与土地利用的三个指标呈负相关。为了分析农场特征的影响，我们使用以下方法将农场分为四个集群：我们发现，净生产力与饲料转化效率的两个指标呈正相关，与土地利用的三个指标呈负相关。为了分析农场特征的影响，我们使用以下方法将农场分为四个集群：基于这些对粮食安全贡献的指标进行k均值聚类，然后进行冗余分析以选择最具影响力的农场特征，旨在突​​出对比农场策略。最高的净生产力是通过“集约化和净效率”的农场战略实现的，该战略具有集约化的草本管理、每头奶牛的高产奶量、适当使用浓缩液以及管理良好的奶牛饲养者（即后备小母牛和犊牛）。新开发的净生产力指标可通过同时考虑人类食用蛋白质和农业用地的使用来量化乳制品系统对粮食安全的贡献。