Review on euthanasia of suckling piglets on farm

The majority of animal losses in pig production occur during the first days postpartum, i.e. in new-born piglets. The necessity to euthanasia occurs particularly during this first period of pigs' life. The review will therefore focus on the euthanasia of suckling piglets. This group includes all such piglets until they are ready for weaning (up to 10 kg approximately). Euthanasia (“good death, in Greek “eu” meaning “good” and “thanatos” meaning death) includes ending the life of an individual animal in a way that minimizes or eliminates pain and distress (American Veterinary Medical Association [AVMA], 2020). This corresponds to the general requirement of the Council Regulation (EC) No 1099/2009 to protect animals at the time of killing such that they are spared any avoidable pain, distress or suffering (Article 3). The Regulation thus recognises that killing animals may induce pain, fear and distress even under the best available technical conditions. Therefore, any person involved in the stunning or killing of animals should take the necessary measures to avoid pain and minimise distress and suffering during the killing process, considering the best practices in the field. The main reasons for euthanizing a piglet are described below (including incurable diseases and injuries).
The killing procedure must spare animals any avoidable pain, distress or suffering. This implies that moving animals to the killing point and restraining them for the purpose of stunning and killing must be done without causing undue fear and distress. Animals may show the latter by vocalising and/or trying to escape. For killing animals, one-step procedures should be primarily used that lead directly to death without the application of any further subsequent killing procedure (e.g. bleeding). These one-step procedures are recommended from an animal welfare perspective to minimize the risk of application errors and from the user's point of view to reduce mental stress. The second step itself may additionally contribute to the mental stress of the person performing the procedure (Marahrens, 2014b). Only common methods that can be used by farmers are addressed. Basis is the EU legislation, but references are made to significant national differences. Additionally, new developed methods, not yet covered by the Regulation, are described.
Operators must affirm death of animals by confirming the absence of vital signs of cardiovascular, respiratory and neuronal functioning. Best practices maximally limit stress during handling and killing processes. This review should help to develop guides to good practice on operating and monitoring procedures for killing animals and to provide proper guidance on animal welfare for both, inspectors and business operators. It highlights the four key areas relevant for animal welfare at the time of stunning and killing, some of which can be subdivided further into appropriate decision-making on euthanasia, handling and moving piglets to the killing point, the killing process (physical and gas killing methods including restraint, if necessary), and post-mortem inspection of the carcass.
The review addresses the underlying scientific knowledge and key areas to focus on during welfare inspections related to on-farm euthanasia of suckling piglets. The review focuses on how to minimise welfare problems and facilitate improved practices, as well as the underlying legal requirements. This review will not deal with large-scale killing or depopulation.