In current livestock farming practice, a number of painful procedures, often termed as mutilations, are carried out on animals for purposes associated with the prevention of injurious behaviour, identification of individuals, improving ease of management, or enhancement of product quality. Amongst these, the most widespread is the practice of castration of male animals, done in most species to avoid unwanted breeding, prevent the development of undesirable and possibly injurious male sexual behaviours, and prevent the development of unpalatable male odours and flavours in the meat. Whilst the practice of castration is subject to some legal restriction, it is still the case that each year many millions of farm animals are subject to a painful procedure that is often carried out without anaesthesia or analgesia. This has become a subject of increasing public concern, which has been particularly focussed on pigs because the anatomy of this species has meant that only surgical methods have been possible until very recently. As a result of this concern, the European Union (EU) commissioned a specific scientific review of the welfare issues associated with the castration of piglets by European Food Safety Authority (EFSA) in 2004, and subsequently a Specific Support Action (Attitudes, practices and state of the art regarding piglet castration in Europe, PIGCAS) to review the state of the art and critically appraise possible alternatives to the current widespread practice of surgical castration without pain relief.
This themed volume of Animal contains a series of papers arising from the PIGCAS project. At the outset of the project, it was apparent that there was limited information on the current practices for pig castration in different EU member states. This was addressed by carrying out an EU-wide survey, whose results are reported in the first paper (Fredriksen et al., Reference Fredriksen, Font i Furnols, Lundström, Migdal, Prunier, Tuyttens and Bonneau2009). This shows wide variation in the timing, methods and extent of pain relief used in practice. Whilst EFSA has previously reviewed the welfare aspects of piglet castration (EFSA, 2004; Prunier et al., Reference Prunier, Bonneau, von Borell, Cinotti, Gunn, Fredriksen, Giersing, Morton, Tuyttens and Velarde2006), there has since been substantial scientific activity in this subject area and more extensive evaluations of some of the existing and newly available practical alternatives. An updated review is therefore the subject of the second paper (von Borell et al., Reference von Borell, Baumgartner, Giersing, Jäggin, Prunier, Tuyttens and Edwards2009). The relative merits of the possible solutions involving different approaches to anaesthesia and analgesia have generated much scientific debate and there is still not a consensus on this subject. This is shown by the letters to the editor which are also published in this issue (Gerritzen et al., Reference Gerritzen, Kluivers-Poodt, Reimert, Hindle and Lambooij2009; Wright et al., Reference Wright, Whiting and Taylor2009), and which relate to comment on an earlier paper on the subject published in Animal (Gerritzen et al., Reference Gerritzen, Kluivers-Poodt, Reimert, Hindle and Lambooij2008).
Castration of male pigs may offer some advantages for subsequent ease of management and reduction in undesirable male sexual behaviours that may pose a risk to welfare of other animals. However, the primary reason for the continuation of castration as a widespread practice is the need to safeguard meat quality. This aspect is reviewed in the third paper (Lundström et al., Reference Lundström, Matthews and Haugen2009), which gives particular attention to the risk of boar taint in the carcass and the potential for on-line methods for its detection. A further paper (Zamaratskaia and Squires, Reference Zamaratskaia and Squires2009) reviews the biochemical regulation of boar taint compounds in more detail and explores possible future immunological, nutritional and genetic approaches to minimise the problem. Ultimately, in the assessment of different future strategies to enhance animal welfare whilst safeguarding meat quality, it is important that the scientific knowledge is integrated with a review of the economic implications. This is the subject of the final paper in the series (de Roest et al., Reference de Roest, Montanari, Fowler and Baltussen2009). Together, these five review papers provide a comprehensive and current analysis of the issue of castration in pigs, which can inform both future scientific initiatives and policy decisions in this important subject area.
