Richard B. D’Eath

The Natural Behaviour of the Pig

In a book about the welfare of the pig, the need to understand the natural behaviour of the pig will be immediately obvious to those who define good welfare in terms of an animal’s capacity to behave in a natural way (KileyWorthington, 1989; Rollin, 1993). Other authors prefer to define welfaremainly in terms of health and biological functioning (Broom and Johnson, 1993), or in terms of subjective mental states or feelings (Dawkins, 1990; Duncan, 1993; reviewed by Fraser et al., 1997). However welfare is defined, knowledge of natural behaviour can be useful in identifying welfare problems. Recent changes in husbandry and housing environments have occurred relatively rapidly in the context of both evolutionary time, and the domestication history of the pig. As a result, welfare problems can arise due to a mismatch between the pig’s behavioural needs and its environment. Problems can occur where natural behaviour is thwarted (e.g. a sow attempting to nestbuild without substrates and in a restricted space) or is inappropriately redirected (e.g. tail-biting). Studying the unrestricted behaviour of pigs in a natural setting can provide useful information about the range and role of behaviours that pigs perform, and their choices and use of habitat could provide clues to their housing needs. When behaviour in natural and more intensive environments is contrasted, differences in behaviour may reveal aspects which are prevented or not stimulated (Graves, 1984; Stolba and Wood-Gush, 1989; Mendl, 1995; SVC, 1997). Stolba and Wood-Gush (1984) directly applied this thinking by studying free-ranging pigs, and identifying key environmental features to apply directly to a new housing system design (see also Arey and Brooke, 2006). At the end of this chapter, we return

Transcriptional responses of PBMC in psychosocially stressed animals indicate an alerting of the immune system in female but not in castrated male pigs

BackgroundBrain and immune system are linked in a bi-directional manner. To date, it remained largely unknown why immune components become suppressed, enhanced, or remain unaffected in relation to psychosocial stress. Therefore, we mixed unfamiliar pigs with different levels of aggressiveness. We separated castrated male and female pigs into psychosocially high- and low- stressed animals by skin lesions, plasma cortisol level, and creatine kinase activity obtained from agonistic behaviour associated with regrouping. Peripheral blood mononuclear cells (PBMC) were collected post-mortem and differential gene expression was assessed using the Affymetrix platform (n = 16).ResultsRelevant stress-dependent alterations were found only between female samples, but not between castrated male samples. Molecular routes related to TREM 1 signalling, dendritic cell maturation, IL-6 signalling, Toll-like receptor signalling, and IL-8 signalling were increased in high stressed females compared to low stressed females. This indicates a launch of immune effector molecules as a direct response. According to the shifts of transcripts encoding cell surface receptors (e.g. CD14, TLR2, TLR4, TREM1) the study highlights processes acting on pattern recognition, inflammation, and cell-cell communication.ConclusionsThe transcriptional response partly affected the degree of ‘stress responsiveness’, indicating that the high stressed females altered their signal transduction due to potential infections and injuries while fighting.

Mitigating hunger in pregnant sows

Abstract Pregnant (dry) sows are fed a restricted food ration to ensure good health, production and longevity, but this results in behavioural signs of hunger: oral behaviours increase and may be redirected ‘unnaturally’ towards non-food, prompting welfare concerns. ‘Dietary fibre’ encompasses a variety of chemical classes, with a variety of physiochemical properties. It reduces abnormal oral behaviours, and fibres that are soluble and fermentable in the hindgut appear to prolong satiety, reduce activity and improve welfare. EU rules require fibre in dry sow diets and access to foraging materials but implementation differs across member states. Diet, feeding system, number of meals and social structure combine to affect welfare of the sow and developing piglets, e.g., through pre-natal stress. Current breeding trends to increasing litter size and associated practices like the use of ‘nurse sows’ may require a rethink of sow nutrition to safeguard longevity and welfare.

Breeding for pig welfare: Opportunities and challenges

Acceptable animal welfare is an integral part of sustainability. Selective breeding for improved animal welfare, as well as being a direct goal itself, can benefit the economic and environmental aspects of pig farming. Several traits have major welfare consequences but have proved difficult to improve through management change alone. Here we consider how past selection for productivity has affected welfare and give three examples of the state of the art in selective breeding for welfare traits in their own right. Selection for complex welfare-relevant traits poses practical, economic and ethical challenges. Current and emerging innovations will significantly reduce the economic and practical barriers to breeding and allow efficient selection for traits that previously have been too expensive to record. Examples will be given of the new phenotyping techniques and genetic methodologies that are expanding the range of welfare traits that selection pressure can be exerted upon.