Feeding livestock food residue and the consequences for the environmental impact of meat

The environmental impact of meat is high mainly due to the feed required by livestock in combination with the impacts of cultivating, transporting and processing of feed crops such as tapioca and grains. Like regular feed crops, livestock also feed on residue from the food industry, such as pulp, scrap and peels. Both types of raw material have different environmental impacts. Feeding food residue to livestock is an efficient way to upgrade a low quality material into high quality foods. In the Netherlands, food residue represents the majority of the feedstock for feed. Distinguishing crops from food residue has consequences for the ascribed environmental impact of meat. This paper separates these two streams using volume, environmental impact and their relevance in meat production. An assessment is made of three food industries (sugar beet industry, vegetable oil industry and potato product industry) that produce the largest stream of food residue, and of the pork industry, as an example of meat production. The environmental impact of food residue-based feed is allocated in three different ways: mass ratio, economic basis, and no assigned burden. We found that the amount of pork produced from food residue is substantial. The environmental impact of food residue-based feed is also significantly lower than grain-based feed. We discuss changes in vegetable and in animal product consumption that influence the environmental impact of pork. It is concluded that the use of current food residue keeps the environmental impact of livestock foods relatively low. However, a further increase in meat consumption would require more feed grains with a correspondingly larger environmental impact because food residues are used up.