Farming contributes to the sustainable production of proteins

Animal production is often incriminated for its inefficacity in using plant proteins, which seems to be confirmed by raw statistics. It takes about 2 and 10 kg of plant proteins to make up about 1 kg of proteins of animal origin. But these overall numbers ignore that proteins from meat or milk have a greater nutritional value than plant proteins and that it is necessary to eat 20 to 25% more to cover daily protein needs. They ignore that animals eat plant proteins that cannot be used in human foods and they graze on surfaces that cannot be used to produce annual cultures. The real contribution of animals to protein safety must therefore be evaluated by comparing the proteins produced and the plant proteins that can be consumed by humans but which are consumed by animals. Meat production with grazing cattle is overall neutral; that is to say it produces as much proteins consumable by human it consumes vegetable proteins that could have been directly used as human food. When cattle are fed large amounts of concentrate in order to attain their full production potential they generally produce slightly less protein than they consumed valuable protein for human food. These results underline an important tension between the necessity to have animals with rapid growth to satisfy a growing need for animal proteins and the necessity to limit competition between animals’ and human’s need for proteins. There is still room for progress to improve the efficiency of protein use notably by using alternative protein sources and by well-organized complementarity between plant and animal production on the regional scale in order to maximize the production of proteins that can be consumed. These points are discussed in this article.