Development of non-aversive stunning methods for pigs

In EU pig slaughterhouse two stunning methods are commonly applied: electrical stunning and carbon dioxide stunning at high concentrations. In 2004 and 2020, the European Food Safety Authority (EFSA) concluded for the gas stunning of pigs that at concentrations above 30% CO2, the gas is aversive and causes hyperventilation and irritation of the mucous membranes. This is likely to be painful, and elicits hyperventilation and gasping before loss of consciousness. For this reason, high concentration CO2 stunning has been criticized.
The general objective of this project is to encourage EU pig slaughterhouses using high carbon dioxide concentration for stunning pigs to convert to more animal welfare friendly systems, by developing technical specifications for four promising alternatives. Three of these alternatives involve gas stunning, one of them aims at improving electrical stunning process. They are:
1 Marel System lead by Marel. System that facilitates in pre-grouped animals transported into a multi-phase-stunning system. Starting point is CO2. The unit can be equipped to facilitated other gas mixtures.
2 Helium lead MRI. It involves helium in a one- or two-phase stunning system in combination with nitrogen.
3 TIGER lead by FLI. This is a gas stunning system that can be retrofit to existing Dip-Lift and paternoster stunning devices to allow for stable gas mixtures of alternative gases at very low oxygen levels.
4 Improved Electrical Stunning developed at Compaxo. This approach will look at ways to improve the process of electrical stunning with special emphasis to pre-stunning handling, design of raceways and entrance of pigs into the stunner.
For each of them, there is scientific literature available that points to improvement of animal welfare. However, before they can be further developed and tested at commercial line speeds, the technical settings need to be optimised and remaining practical difficulties need to be overcome. This will be done through 5 different work packages:

WP1. Descriptive phase: the description of the current stunning practices for pigs in high throughput slaughterhouses and their socio-economic drivers.
WP2. Planning phase: the selection of alternatives to high CO2 stunning that can be tested in the PigStun project, as well as the technical and socio-economic data that needs to be collected.
WP3. Implementing phase: the implementation of the selected alternatives under commercial conditions or conditions similar to the commercial situation, and the collection of the pre-defined types of data.
WP4. Analytical phase: the analysis of data collected and the production of recommendations for facilitating the transition towards any proposed alternatives.
WP5. Dissemination phase: the production of communication materials and their dissemination to the target audience.

The beneficiaries and associated partners of the PigStun consortium come from four leading pig producing countries: The Netherlands, Denmark, Germany and Spain. They include academic research partners Wageningen Research (NL), Aarhus University (DK), Friedrich Loeffler Institut (DE), Max Rubner Institut (DE) and IRTA (ES). It also includes developers of slaughter house equipment Marel Meat BV (NL), Danish Meat Research Institute (DK) and Air Liquide (DE). Finally, five pig slaughter companies are involved: Compaxo Vlees (NL), Danish Crown (DK), Norfrisa (ES), Vion Perleberg (DE) and Westfort Meat (NL).
The results of the project will be published and widely communicated. All disseminated materials will be kept traceable and digitally available after the project finalizes in close collaboration with the European Union Reference Centre for Animal Welfare (EURCAW-Pigs), thus contributing to medium-term outcomes and long-term impacts set in the project.