Research
Our research group focuses primarily on the sustainable nutrition of livestock animals, with particular emphasis on ruminants, pigs, and poultry. At the core of our work is the development of feeding strategies that contribute to reducing competition for food and land, conserving natural resources, and promoting circular economy – for example, by maximizing the use of human-inedible biomass from permanent grasslands and/or by-products of food processing.
Another key research area is feed conservation, especially the conservation of alternative protein sources (e.g., insect protein). Our research also focuses on the development of innovative conservation approaches, such as the use of enzyme complexes derived from anaerobic rumen fungi to improve forage quality ‘post-harvest’, or the targeted increment of mineral bioavailability using organic acids.
In the context of climate change, we develop feeding strategies to adapt animal nutrition to the reduced availability of high-quality feed and water. We also investigate the impact of increasing stressors in livestock production, such as heat stress and the growing exposure to various feed contaminants. In this regard, we place a strong focus on feed safety, particularly the occurrence and effects of mycotoxins, in line with the One Health approach.
Our research combines a broad methodological spectrum of feed science, including both in vitro and in vivo models, and is embedded in interdisciplinary collaborations at the interface with different research disciplines – predominantly microbiology, agricultural engineering, animal breeding, veterinary medicine, as well as nutritional and food sciences.
Current doctoral theses
Nitrogen (N) is not utilized efficiently in dairy production systems. Grassland forages represent a regionally produced and cost-effective feed source with high potential to enhance nitrogen utilization. However, conservation of the forages diminishes their protein quality, which – although not entirely avoidable – can be influenced by several factors. This project investigates two different approaches aimed at improving the protein and energy supply in ruminants by comparing differently preserved grasses and legumes. A comprehensive characterization of the conserved forages will be carried out using various analytical methods. As feed intake is a critical factor in animal production, the conserved forages will subsequently be evaluated in preference and feeding trials with goats. These trials will assess both the acceptance of the conserved forage types as well as the impact on feed intake and milk performance. This integrated approach will provide in-depth insights into the effects of different conservation strategies on forage protein quality, enabling the formulation of practical recommendations for agriculture (OptiKons).
Funded by the German Federal Ministry of Food and Agriculture based on a resolution of the German Bundestag.
The aim of this project is to develop a practical laboratory-based approach to estimate the standardized ileal digestibility of crude protein (SID-CP) and amino acids (SID-AA) in pig feeds. This enables the use of small seeded legumes in a sustainable, performance-oriented, and N-reduced protein supply in livestock production – taking into account specific characteristics and variation in protein quality. Existing data gaps will be closed, thereby improving the utilization, acceptance, and economic viability of legume-based feeds. By comparing in vivo data with laboratory-based results, a reliable prediction equation for SID-AA can be developed. Based on the extensive analytical dataset, a NIRS calibration will be created, allowing rapid, practical, and cost-effective assessment of protein quality. This ultimately supports N-optimized feeding strategies. The project contributes to the integration of regional legumes into efficient feeding systems that harmonizes animal requirements (animal health), economic considerations (flexible ration design, optimized production processes), environmental policies (reductions in greenhouse gases and nitrate in water, improved nutrient balances), and societal expectations (ecological sustainability, avoidance of animal testing and GMO soy) in a coherent and future-oriented manner (KLEE).
Funded by the German Federal Ministry of Food and Agriculture based on a resolution of the German Bundestag.
Soybean meal is a predominant feedstuff in the European poultry and pig production. However, its use is increasingly being criticised, primarily due to the strong dependency on imports from overseas („protein gap“), ecologically questionable cultivation practices and public concerns regarding genetically modified plants. The local cultivation of soybeans is not yet providing sufficient amounts to meet the current demand in livestock feeding. Likewise, the use of alternative local protein crops and oilseeds is limited due to their lower protein quality and the presence of antinutrive substances.
Given these challenges, larvae of the insect species Hermetia illucens are gaining attention as a promising alternative protein source. So far, the larvae are commonly dried to obtain a storable feedstuffs. This process, however, is associated with a high energy demand, hence reducing the overall sustainability and economic efficiency. One potential solution may be the efficient conservation of larvae by ensiling or acidfication.
The present project therefore conducts comprehensive research on the conservation of both untreated and defatted Hermetia illucens larvae. This comprises the investigation of the effects of different co-substrates and preservation additives on conservation success, nutrient composition, hygienic quality and feed acceptance by the animals. Consequently, the project aims to develop a future-oriented, sustainable, and storable insect-based feedstuff that can be used as an alternative protein source in poultry and pig feeding (SiLarve).
Funded by BIOS Science Austria – Association for the Advancement of Life Sciences within the framework of achieving the „UN Sustainable Development Goals“
Funded by the Federal Ministry of Agriculture, Food and Regional Identity on the basis of a resolution of the German Bundestag as part of the BMLEH Protein crop strategy
Further Research Projects
For the first time a practical approach for the estimation of the standardized precaecal digestible crude protein (cdCP) and amino acids (cdAA) in feedstuffs for poultry is being developed. With regard to specific characteristics and the range of variation in the protein value between e.g. varieties, locations and years of cultivation this enables the use of small-seeded legumes in a performance-based and nitrogen-reduced protein supply in animal production possible. Existing data gaps will be closed; this has a positive impact on use, acceptance and economy of legumes. Protein sources of various origin/treatment are characterized by non-fibre bound amino acids. By comparison of in vivo data with laboratory analytical results a generalised estimating equation for cdAA may be derived. A nitrogen-optimized feeding strategy will be possible and include the use of local, i.a. specifically-treated feedstuffs trough precise combination of various protein sources and gains and supplementation of specific amino acids. A unique pool of samples of up to now 200 feeding stuffs (legumes and soybean-based commodities, various treatments and genotypes) and 100 compound feeds, of which cdAA in poultry has already been determined in vivo, is available. Thus regionally produced legumes may be integrated in efficient feeding strategies thereby harmonising animal requirements (animal health), economic (flexible planning of rations, optimised production processes) and ecopolitical needs (reduction of greenhouse gases and nitrate in ground water,) as well as social expectations (ecology, reduction of animal experiments and GMO soy). In this project an equation will be developed to estimate the precaecal digestible amino acids (cdAA) of poultry diets using a laboratory method and solutions will be given.
Alfalfa (Medicago sativa L.) is one of the most important forage crops in ruminant nutrition, supplying animals primarily with crude protein, energy, calcium, and structural fiber. However, the proportions of the ingredients change significantly over the course of the growing season: the crude protein content declines while the proportion of cell wall constituents (NDF) increases. On the one side, this shift directly reduces the feed value. On the other side, the total biomass yield continues to rise with plant maturity. The central challenge is therefore to determine the optimal harvest date by balancing feed quality and harvest yield. The heterogeneous development of large stands – driven by abiotic and biotic factors – makes uniform assessments indeed challenging. Our research addresses this issue by deploying UAV‑based drone systems for objective, field‑wide monitoring of the alfalfa stand status. Regular flights equipped with RGB cameras and LiDAR scanners generate high‑resolution point clouds that document canopy development over time. In parallel, we collect alfalfa samples for laboratory analysis of key feed value parameters, notably crude protein and NDF. The project aims to determine the correlation between UAV‑derived growth variables and traditional feed value metrics, thereby providing practical decision‑making tools for determining the optimal harvest window.
This work is a collaboration between the Animal Nutrition group and the Geodesy group or the Bonn Excellence Cluster PhenoRob (“Robotics and Phenotyping for Sustainable Crop Production”) at the Frankenforst campus.
Doctoral Theses
2024
Ziade Abraha Kahsay
Chemical composition and in vitro evaluation of the feeding value of brewery by-products for ruminants - An ethiopian perspective.
Dissertation, Rheinische Friedrich-Wilhelms-Universität Bonn, 2024.
Deitmers, Jan-Helge
Quantitative evaluation of ruminal nutrient degradation using in situ and in vitro methods.
Dissertation, Rheinische Friedrich-Wilhelms-Universität Bonn, 2024.
https://bonndoc.ulb.uni-bonn.de/xmlui/handle/20.500.11811/12084
Schmitz, Klara Theresa
Analytical and nutritional evaluation of rye grain in diets for growing pigs.
Dissertation, Rheinische Friedrich-Wilhelms-Universität Bonn, 2024.
https://hdl.handle.net/20.500.11811/11340
2023
Enke, Nick
Drinking behaviour of Ilamas (Lama glama) and horses (Equus caballus) in response to saline drinking water.
Dissertation, Rheinische Friedrich-Wilhelms-Universität Bonn, 2023.
https://hdl.handle.net/20.500.11811/10722
2020
Denißen, Jana
Fütterungsstrategien zur Optimierung der Energie- und Nährstoffversorgung laktierender Milchkühe.
Dissertation, Rheinische Friedrich-Wilhelms-Universität Bonn, 2020.
https://hdl.handle.net/20.500.11811/8569
Schemmer, Ralph
Phosphorus digestibility and metabolizable energy concentrations of contemporary cereal grain varieties fed to growing pigs.
Dissertation, Rheinische Friedrich-Wilhelms-Universität Bonn, 2020.
https://hdl.handle.net/20.500.11811/8907
2019
Scherer, Rebecca
Impact of ensiling conditions on formation of biogenic amines in grass and legume silages and feed intake behaviour of goats.
Dissertation, Rheinische Friedrich-Wilhelms-Universität Bonn, 2019.
https://hdl.handle.net/20.500.11811/7991
Rombach, Markus
Differentiated identification of behavioral elements during herbage intake – a tool for intake estimation of grazing dairy cows.
Dissertation, Rheinische Friedrich-Wilhelms-Universität Bonn, 2019.
Hartinger, Thomas Dietmar Said
Effects of pre-ensiling treatments on quality of lucerne silages, in vitro rumen fermentation and microbiota composition.
Dissertation, Rheinische Friedrich-Wilhelms-Universität Bonn, 2019.
https://hdl.handle.net/20.500.11811/8027
2018
Brüning, Dave
The effect of air exposure before and after ensiling on maize silage quality and dietary choice by goats.
Dissertation, Rheinische Friedrich-Wilhelms-Universität Bonn, 2018.
https://hdl.handle.net/20.500.11811/7352
Rauen, Anna Christina
Nachhaltigkeitsbewertung in der Rinderhaltung – Entwicklung eines indikatorenbasierten Systems zur Bewertung der Fütterung.
Dissertation, Rheinische Friedrich-Wilhelms-Universität Bonn, 2018.
2017
Böttger, Christian Georg
Laboratory evaluation of the nutritional value for ruminants of European distillers dried grains with solubles.
Dissertation, Rheinische Friedrich-Wilhelms-Universität Bonn, 2017.
Trautwein, Julia
Lucerne silage for high yielding dairy cows – evaluation of the nutritional value using chemical and in vivo methods.
Dissertation, Rheinische Friedrich-Wilhelms-Universität Bonn, 2017.
https://hdl.handle.net/20.500.11811/7325