iREACT

Intensive beef production faces criticism regarding its environmental footprint, low efficiency in converting grain feed into human edible proteins, and concerns about animal welfare and human health risks when too much beef is consumed. However, when beef cattle are fed mainly with grass, farming systems are more sustainable and provide numerous ecosystem services. These benefits include, among others, maintaining the biodiversity of grasslands, offsetting greenhouse gas emissions by grassland carbon fixation, vitalising the soil through manure production, producing highly nutritive meat for humans, and supporting the income and livelihood of many rural areas where economic alternatives, including agricultural ones, are rare. The introduction of grass-fed cattle production should be considered in the context of a circular economy at the territorial scale, as well as for local and global food security, as beef cattle produce more highly valuable proteins for humans than they consume. These many advantages make such systems fully compliant with agroecological principles. Nevertheless, beef meat production from grass remains a challenging task for farmers. Grass availability remains seasonal, uncertain, and sensitive to climate changes, resulting in disrupted cattle production itineraries and the discontinuous availability of nutrients. For beef cattle, this means that maintaining a satisfactory level of growth performance without compromising animal health and welfare or meat quality is a priority. The rationale of the iREACT project is that beef-on-dairy crossbred cattle combine high efficiency and resilience capabilities due to their ability to deposit fat tissue relative to muscle (high fat-to-lean ratio) and consequently mobilise body energy reserves when faced with periods of reduced feed availability. Further, their ability to transform grass into proteins may improve competitiveness and reduce the environmental footprint. The main question addressed in iREACT is, “Does a variability in the fat-to-lean ratio induced by the crossbreed and grass-feeding practices differentially influence the metabolic resilience and adaptability of beef-on-dairy heifer, as well as the trade-offs among meat qualities and economic and environmental impacts? Thus, iREACT targets the following objectives: • To develop tools for monitoring and predicting the fat-to-lean ratio during heifers’ growth • To understand the biological drivers of the fat-to-lean ratio, resilience and adaptive capabilities through large-scale molecular phenotyping and integrative analyses • To select image- and molecular-based features related to the fat-to-lean ratio, resilience, and adaptive capabilities for future phenotyping of bovine genetic resources for these traits • To quantify the trade-offs among carcass quality, meat nutritional and sensory values, and economic and environmental impacts in grass-based beef-on-dairy systems compatible with agroecological practices The originality of iREACT lies in its integrative biology approach, encompassing feed, animal, and meat sciences, biochemistry, imaging, proteomics, lipidomics, data modelling, mechanistic modelling, and statistics. To achieve its goals, iREACT leverages a multidisciplinary approach to provide fundamental knowledge about the biological drivers of the fat-to-lean ratio and its applied benefits. For farmers and public policy bodies, iREACT will deliver guidelines for the efficient use of grass-based diets, ensuring meat production all year round and providing valuable food for human consumers, as well as economic and environmental evaluations of the practices of “beef-on-dairy bovine fed with grass-based diets”. Several well-designed and reliable modelling and imaging tools will be offered to scientific and R&D communities interested in the prediction and phenotyping of the bovine fat-to-lean ratio. Lastly, new methods for the longitudinal integration of heterogeneous data will be developed.