Reducing enteric emissions in dairy cattle through feeding strategies

General introduction

The VLAIO LA project HappyCliMi has demonstrated that there are several targeted feeding strategies for dairy cattle that can reduce the animals' enteric methane emissions while maintaining or even increasing milk production. In addition to the already documented ration with rapeseed meal and brewers' grains, the methane-reducing capacities of duckweed, the brown seaweed Alaria, and hop cones have now also been substantiated. Enteric emissions are methane emissions from the rumen of ruminants and constitute a significant part of the climate impact of cattle farms. Within the Covenant on Enteric Emissions from Cattle (CEER), it is crucial that livestock farmers can choose from a sufficient number of recognized, practical methane-reducing measures. That is why the project focused on refining and possibly expanding the list of recognized feed materials and additives, with a focus on broad applicability in Flemish dairy cattle rations. 

Research approach

In a first step, the researchers screened the methane-reducing potential of several dozen feed materials, including by-products and new raw materials, as well as feed additives, in vitro. The aim was to identify options that could also be used in the medium and long term for cattle farming. In addition, practical research was conducted to determine whether the recognized measure involving rapeseed meal and beer draff could be applied more widely in Flanders. At four dairy farms with different basic rations, rations with extra rapeseed meal and brewers' grains were compared with the standard ration. Enteric emissions, dry matter intake, and milk production were accurately measured to assess the effectiveness and practical feasibility of this feeding strategy under realistic farm conditions.

Relevance/Valorisation

The final results show that the covenant measure 'rapeseed meal and beer draff' can be applied more widely in practice. Concrete reduction percentages are available: Compared to the basic ration, a ration rich in rapeseed meal and brewers' grains achieved a methane reduction of 2.4%. As there was no impact on dry matter intake and milk production increased by an average of 4.6%, this led to a 5.6% reduction in methane per kg of dry matter intake and an 8.2% reduction in methane per kg of milk. The project also identified three new feed ingredients with methane-reducing potential: duckweed, the brown seaweed Alaria, and hop cones, which deserve further study for inclusion in future lists of measures. These results are directly relevant to dairy farmers, feed specialists, and policymakers who are committed to feasible feed measures to achieve the CEER targets.