Breeding for improved welfare in pigs: a conceptual framework and its use in practice

Abstract

Welfare of animals can be defined as the kind of feelings the environmental conditions bring about in the animals. These feelings depend on the needs of the animals and their degree of satisfaction. Needs of animals, and so their welfare, are partly genetically determined. Therefore, welfare can be changed by breeding. The aim of this study was to investigate how welfare of pigs under modern intensive farm conditions can be improved by genetic selection, with emphasis on the precise definition of the breeding goal and determination of the animal characteristics on which selection can be based in practice. The existing thermoregulation model was used to develop a conceptual framework that describes welfare of growing pigs and production sows with respect to each of their needs as a curvilinear function of the respective environmental conditions. The framework assumes that welfare in terms of feelings is reflected by the physiological and behavioural mechanisms the pig has to activate in order to cope with the various environmental conditions it encounters. Based on those physiological and behavioural responses to changing conditions, five welfare zones can be distinguished for each need. Breeding goals for welfare were defined in terms of the transition points between these welfare zones, such that future pigs would better cope with unfavourable or unfamiliar farming conditions, therewith quickening the domestication process, to some extent. However, as long as genetic parameters for these transition points are not available, more common welfare-related characteristics like temperament, stress resistance and robustness can be included in the breeding goal, as an alternative.For selection among potential breeding candidates, transition points between welfare zones can be determined in sib tests, thereby also collecting the data for estimating genetic parameters. As a cheaper alternative, breeding candidates could be tested under hard conditions and selected on their coping success. In addition, various behavioural tests and operant conditioning tests (to test a pig's motivation to change its actual environment) can be carried out. Under common conditions on the farm, problems associated with coping (like incidences of diseases, injuries, and stereotypies) and/or other relevant traits (e.g. saliva cortisol levels, longevity and even production traits) should be recorded routinely and used as selection index information. Selection for improved welfare should lead to more tolerant pigs that are better able to cope with possible unfavourable farm conditions by a more efficient use of the adaptation mechanisms they already possess. It should, however, not result in lowering husbandry standards. More research is needed to assess genetic correlations among various welfare aspects and with production traits to prevent undesired side effects in future populations of pigs.

Genetic parameters for androstenone, skatole, indole, and human nose scores as measures of boar taint and their relationship with finishing traits1

“…Breeding can be useful as a tool to increase animal welfare (Kanis et al, 2004). Breeding against boar taint to avoid castration of piglets is just one example.…”

Bayesian Analysis of Genetic Associations of Skin Lesions and Behavioural Traits to Identify Genetic Components of Individual Aggressiveness in Pigs

“…Indicator traits that can be rapidly assessed and are genetically correlated to the goal trait of reduced aggressiveness, are therefore of great interest. The association between many indicator and behavioural goal traits has only been demonstrated at the phenotypic level, from which it is difficult to predict the likely success of selection (Kanis et al 2004). In pigs, several studies with large sample sizes have used the number of skin lesions following mixing as a proxy measurement of engagement in reciprocal fighting when observing large populations (e.g.…”

Génétique de l’adaptation comportementale des animaux aux conditions d’élevage : le cas des productions bovines, porcines, avicoles et aquacoles

“…Au final, il devient opportun de définir des objectifs de sélection plus équilibrés (Kanis et al 2004, Olsson et al 2006, en incluant des caractères de comportement pour accroître la capacité d'adaptation des animaux, ce qui requiert en amont de s'assurer que les conditions d'élevage répondent aux besoins comportementaux des animaux.…”