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Livestock-based bioeconomy

The 75th annual conference of the Society of Nutrition Physiology (GfE) from 16 to 18 March 2021 was intended to be a very special anniversary event, which it ultimately was since it took place in exclusively digital form. In scientific dialogue, the participants focussed on the perspectives and the conflicting objectives in the use of livestock in the agricultural production of food of animal origin

(GfE). The essential future scenario of agricultural animal production is concealed in the exploitation by livestock of biomass that cannot be eaten directly by humans. Because unequivocally foregoing livestock not only equates to an absolute loss of food but also reduces the productivity of crop production or necessitates the increased use of mineral fertilisers.

The question concerning the necessity of livestock goes back to the fundamental principle of primary agricultural production based on crops, since these always contain significant quantities of inedible biomass besides the actual 'food'. This has to be broken down into plant nutrients and returned to the farmland. Farm animals therefore fulfil a fundamental function in maintaining the agricultural nutrient cycle and make an extensive contribution to reducing the use of mineral fertilisers or substituting them.

As 80% of agricultural biomass are not directly edible by humans, the great potential and the unique characteristic farm animals consist of producing edible biomass, i.e. high-quality animal foods, from inedible biomass via the animals' digestion and metabolism. Livestock accomplishes this task in a form that has been established for millennia. A complete bioeconomic analysis of agricultural biomass production must therefore always include livestock as well.

Prof. Wilhelm Windisch (Chair of Animal Nutrition, TUM School of Life Sciences) dedicated this year's plenary address to the research results and correlations concerning 'Livestock-based bioeconomy and the perspectives and conflicting objectives in the role of livestock in the agricultural production of food of animal origin'.

In his remarks, he explained the transformation of biomass into edible protein and the perspectives for the more efficient and sustainable production of food of animal origin. He also took a stand concerning the conflicting objectives, and analysed and questioned the individual technical and social perspectives. As the most important finding, he pointed out that the use in livestock nutrition of organic biomass and numerous by-products that cannot be consumed directly by humans is unavoidable to safeguard the food supply of a continuously growing global population.

This is reflected in the increasing discussion surrounding food competition and will foster livestock systems that offer high potential for using inedible biomass in the future. In order to make the debate concerning food competition between man and animals more objective, the human edible fraction (hef) of the various feeds should be illustrated.

The contribution made by animal production supports the use of co-products from the cultivation of (edible) crops, from inedible biomass from intercrops as part of crop rotation, from (permanent) grassland and by-products from food production and bioenergy production as well as from food residues. In this context, food production has to analysed in the overall system, not merely individual crops within crop rotation. As the emissions also have to be related to the overall system, animal production is ultimately technically responsible for adapting the scope and intensity to the respective regional situation.

The original contribution was published as a book chapter entitled 'Tierbasierte Bioökonomie' in 'Das System Bioökonomie' (Thrän, Moesenfechtel (Eds.) (2020): Das System Bioökonomie. Springer-Verlag, ISBN 978-3-662-60729-9,; the English translation is printed in the current proceedings (see below).

The annual conference is considered to be the most important scientific dialogue platform for animal nutrition focussing on nutritional physiology and animal health in the disciplines of agricultural sciences and veterinary medicine in the German-speaking world.

The call to the conference was heeded by a total of 257 participants from the fields of science, applied research, consulting, the feed industry and other related disciplines, thus highlighting both the high level of interest and the enormous importance of scientific dialogue even under the current constraints.

The basis for the technical debate was provided by 101 appraised scientific contributions (subdivided into 45 brief presentations and 56 posters) which were presented and discussed in various sections. Besides classic topics concerning individual nutrients or digestion and absorption processes, great importance was once again attached to aspects regarding feed evaluation and feeding as well as feeding concepts in interaction with intermediary metabolism, inflammatory processes or conversion in the rumen, for instance.

A workshop on the topic of 'Methane loss reduction in cattle by means of feeding and breeding?' was additionally offered in the technical programme; in a total of four contributions, this dealt with the following aspects:

  • Fundamentals of ruminal methane production, its significance to the greenhouse effect and natural limits of methane reduction – Dr Björn Kuhla (Institute of Nutritional Physiology, Department of Metabolism Efficiency of the Leibniz Institute for Farm Animal Biology, Dummerstorf)
  • Possibility of using mid-infrared spectra (MIR) of milk to estimate the methane emission of cows – Prof. Nicolas Gengler (Gembloux Agro-Bio Tech, University of Liege, Belgium)
  • Role of genetics in methane emission in cattle – Prof. Hermann H. Swalve (Chair of Animal Breeding, Institute of Agricultural and Nutritional Sciences, Martin Luther University Halle-Wittenberg, Halle/Saale)
  • Controlling methane emission through feedingProf. Michael Kreuzer (Chair of Animal Nutrition, Institute of Agricultural Sciences, Eidgenössische Technische Hochschule, Zurich, Switzerland).

The proceedings of the 75th annual conference of the Society of Nutrition Physiology can be purchased from DLG-Verlag ( (price: €29.90 plus postage, ISBN 978-3-7690-4114-9). Other contributions published by the GfE are available via the Society's website ( The 76th annual conference of the Society of Nutrition Physiology is scheduled to be held from 8 to 10 Match 2022 in Göttingen; invitation and registration will take place at a later point in time via the GfE website. DLG manages the GfE.