Welfare measurements of finishing pigs on the day of slaughter: A review

• Pig welfare is described at eight stages on the day of slaughter.
• Behavioral observations are useful for welfare assessment but not for continuous documentation of welfare.
• Automatic blood sampling and analyses may be beneficial for documentation.
• Vocalization seems promising as an online indicator of welfare.

Animal welfare on the day of slaughter is of increasing concern to the authorities and consumers alike, creating a need not only to optimize the welfare of the animals but also to document the level of welfare. The day of slaughter is composed of a variety of stages, initiated when the pigs leave the home pen and including pick-up facilities, transport, lairage, stunning and sticking. At each of these stages, the animals are exposed to different stressors that, both individually and in interaction with one another, can compromise welfare. As part of the initial work aiming to document the welfare of finishing pigs on the day of slaughter, this paper provides an overview of the individual stages including a discussion of potential stressors and potential welfare measurements. These measurements are discussed with regard to their relevance and suitability for documentation of animal welfare on the day of slaughter for development of on-site tools for continuous automatic monitoring of animal welfare.