## 1 Introduction
### EU Strategies for Livestock Management--What Has Been Done So Far and Next Goals  
The demands of the global market, the effects of climate change on biodiversity, and the quality of the soil and water present challenges to the continuing growth in livestock production. To support farmers in addressing these issues and adapting to the shifting attitudes and expectations of the public, EU agriculture policy has undergone significant transformation in recent decades [22]. The EU presides over several sectors, among which are climate, energy, agriculture, research, and innovation.  
As an example, the European Green Deal focuses on three fundamental objectives for clean energy transition that are expected to help reduce GHG emissions: (i) to guarantee a secure and affordable EU energy supply, (ii) to modernise the EU energy market, and (iii) to prioritise energy efficiency, primarily concerning renewable sources [5].  
The Farm to Fork Strategy is at the heart of the European Green Deal for a fair, healthy, and environmentally friendly food system. However, the circular bio-based economy is still a mostly unexplored potential for farmers and their cooperatives. As stated in the Farm to Fork Strategy (2020), farmers should take advantage of opportunities to lower  
Figure 1: Pig meat production in 2023 [30; 32].  
methane emissions from livestock by investing in anaerobic digesesters to produce biogas from agricultural leftovers and waste, such as manure, and by developing the generation of renewable energy [33].  
Another important political instrument from the EU is the revised Renewable Energy Directive EU/2023/2413, adopted in 2023, which sets Europe's new 2030 climate targets. Bearing in mind that the energy sector is responsible for more than 75% of the GHG emissions from the EU, it becomes important to increase the share of renewable energy across several sectors of the economy, raising the renewable energy target to a minimum of 42.5% and reducing the GHG emissions by at least 55% by 2030, and aiming to become a climate-neutral continent by 2050.  
In addition, the European Commission has published the REPowerEU plan, which stands on three pillars: save energy, produce clean energy, and diversify the EU's energy supplies. The EU's prospects for achieving the proposed results are promising; the target level for 2020 was exceeded by 2%. Besides being a significant accomplishment, this is also an important milestone on the EU's path towards climate neutrality by 2050.  
Portugal also overachieved its established target for renewable energy in 2020 and is committed to developing strategies for the energy transition. Portugal launched for public consultation (still needs approval to be implemented) a Biomethane Action Plan (BAP) on the horizon of 2024-2040, which represents a strategic vision for the production and application of biomethane, focusing on synergies between sectors. Among the several goals for BAP, there are a few that need to be highlighted, such as: (i) to prioritiise the use of livestock effluent for biogas production; and (ii) to provide agro-industrial and agricultural companies with training and capacity building surrounding the proper operation of anaerobic digesters, including anaerobic co-digestion.  
Although this is not yet a final implementation plan, it is undoubtedly a very important step towards AD promotion and implementation, livestock effluent valorisation (among other waste streams), circular bioeconomy, and energetic transition.