Sustainability, changing animal feed to reduce the consumption of natural resources

The results of a study published on the cover of Nature Food: a replacement of 11-16% of high-energy crops currently used as animal feed with agricultural by-products would save approximately between 15.4 and 27.8 million hectares of land, between 3 and 19.6 km3 and between 74.2 and 137.8 km3 of irrigation water and rainwater

The greater use of by-products in the feed sector in a circular perspective it can lead to a significant savings in the use of land and water resources and therefore to greater sustainability of agri-food systems. This is what is highlighted by a study published on the cover of Nature Food, the result of a collaboration between the Polytechnic of Milan and the University of Milan. At the basis of the work written by Camilla Govoni and Maria Cristina Rulli of the Polytechnic of Milan, Paolo D’Odorico of the University of California at Berkeley and Luciano Pinotti of the University of Milan there is an accurate analysis of the competition for natural resources between the production of animal food and human food and a search for strategies to reduce both this competition and the unsustainable use of natural resources that can derive from it.

I study

The study shows that replacing 11-16% of high-energy crops currently used as animal feed (e.g. cereals) with agricultural by-products would save approximately 15.4 to 27.8 million hectares of land, between 3 and 19.6 km3 and between 74.2 and 137.8 km3 of irrigation water and rainwater.

Agricultural by-products are secondary products derived from the processing of primary crops such as cereals and sugar. The study includes: cereal bran, sugar beet pulp, molasses, distillery residues and citrus fruit pulp. Foods of animal origin are an important source of protein in human diets and contribute on average to 16% of global food needs compared to a use of land and water resources for their production equal to 1/3 of the resources used in agriculture and up to 3/4 of all agricultural land. Animal production can therefore compete directly or indirectly with plant food production.

Less human-animal competition and pressure on resources

“The use of agricultural by-products in animal diets not only competition between sectors and pressure on resources decreasesbut it would also increase the availability of directly consumable calories for the human diet (e.g. cereals) or, in the event that the saved resources are used for other purposes including the production of plant foods lacking in current diets, it would improve food security in various countries, with healthier as well as more sustainable food choices”, comments Camilla Govoni, researcher at the Polytechnic of Milan.

“The use of alternative ingredients in animal diets would result an increase in sustainability and a reduction in environmental impact not only at a local level, where the company raises and produces meat and animal products, but also over great distances. A decrease in the demand for feed, in fact, could lead to a lower importation of the same with consequent economic and socio-environmental benefits. In fact, the production of some feed products corresponds to overpressure on water resources, and deforestation with consequent effects on the concentration of greenhouse gases in the atmosphere, loss of biodiversity, etc. – explains Maria Cristina Rulli, professor of Hydrology and coordinator of the Glob3ScienCE Lab (Global Studies on Sustainable Security in a Changing Environment) of the Polytechnic of Milan – The intersectoral decrease in demand for cereals is of particular importance, in a historical moment in which the supply of these crops is facing serious shortages due to the combination of the ongoing war between Russia and Ukraine, to the residual effects on food supplies of the Covid-19 pandemic and to a decline in harvests caused by increasingly frequent extreme events such as floods, droughts and heat waves induced by climate change”.

“Animal production, by converting fodder and agricultural by-products into products and services with high added value, contributes fundamentally to the modern bioeconomy. Alongside this, livestock farming is often held responsible for a significant environmental impact at a global level, and for this reason it is essential to rethink animal nutrition above all as it is one of the main reasons for competition for resources – concludes Luciano Pinotti, professor of Nutrition and Food of the University of Milan – The approach must be to develop ‘smart animal nutrition’, in which research must propose solutions to increase the production of animal proteins without increasing their environmental footprint. Hence the importance of studying animal nutrition not only in terms of competition, but also of synergies and complementarity with human nutrition, in order to optimize the use of nutrients in the food chain. The main challenge, therefore, is to study innovative and alternative feedstuffs to conventional ones, where possible not in competition with human nutrition, which are part of a circular economy, from a ‘one nutrition’ perspective”.