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The EU project Welfare Quality® proposes an overall assessment system for animal welfare based on animal outcomes. The objective of this study was to test inter-observer reliability (IOR) when assessing lameness, fear and slipping and falling scores as parameters for monitoring the welfare of killing pigs during arrival at the slaughterhouse. Two Belgian and two Spanish slaughterhouses were visited by six to seven observers. Lameness, slipping and falling were assessed twice; during unloading and in the passageway to the lairage zone (lairage). Fear, which was assessed in the unloading area, was based on four indicators: reluctance to move, retreat attempts, turning back and vocalisations. Lameness had low-to-moderate IOR when observed in the passageway to lairage (r=0.46), but the IOR was low during unloading (r=0.25). IOR for slipping and falling was moderate to high (r=0.71 and r=0.50, respectively), when assessed in the unloading area, but low for observations in the passageway (r=0.13). Fear indicators had only moderate or low IOR. Turning back was the measure with the highest IOR (r=0.43) and retreat attempts had the lowest IOR (r=0.25). Based on these results, we concluded that scoring lameness could be reliable when assessed from the unloading bay to lairage, whereas slipping and falling should be scored in the unloading area of the slaughterhouse. We suggest scoring a maximum of two measures of fear on the same animals at the unloading area, with the most reliable parameters being turning back and reluctance to move. The three indicators of animal welfare (lameness, fear and slipping and falling) should be measured in a way to reduce overtax of the observers in order to achieve accurate results. [ABSTRACT FROM AUTHOR]

Stress neuroendocrine systems (hypothalamic-pituitary-adrenal axis and sympathetic nervous system) were studied in 100 female pigs from each of the five main genetic lines used in Europe for pork production: Piétrain, Large White, Landrace, Duroc and Meishan. Levels of cortisol and catecholamines were measured in urine collected at the farm, after transportation to the slaughterhouse and the next morning before slaughter. With the exception of the Piétrain line that showed intermediate levels of cortisol despite its extreme leanness, a significant positive relationship was found between basal cortisol levels and fatness, both across and within (except in Piétrain and Duroc) lines. Basal cortisol levels were 2.46-fold higher in Meishan (20.46 ng/mg creatinine) than in Large White pigs (8.30 ng/mg creatinine), the two extreme breeds. Post-transportation levels were highest but proportional to basal levels, suggesting that the adrenal reactivity to adrenocorticotropic hormone is a major source of variability between lines. Levels of catecholamines were less variable between lines but correlated also with fatness, partlyviapartial correlations with cortisol levels. In serum collected at exsanguination, creatine kinase activity was correlated with muscularity across the five breeds. However, this was due to a much larger activity than expected in Piétrain pigs, although all animals were negative for the allele of the ryanodine receptor gene responsible for stress sensitivity. Serum glucose levels were inversely related to fatness. These data show that the differences between breeds or lines can be utilised by cross-breeding and that this can lead to changes in stress hormones and in turn to some degree of changes in carcass traits.

The behavioral response of piglets in a backtest early in life seems indicative of their coping strategy at a later age. Coping characteristics may depend on the interaction between backtest classification and housing conditions. We studied whether growth rate and partitioning of energy in adult gilts were related to response in the backtest early in life, and to housing in groups or individual stalls. During the suckling period, female piglets were subjected to the backtest. Each piglet was restrained on its back for 1 min, and the number of escape attempts was scored. Thirty-six high-resisting gilts and 36 low-resisting gilts were selected. After weaning, pigs were housed in 12 groups of six (three high-resisting and three low-resisting). From 7 mo of age onward, 36 gilts out of six groups were housed in individual stalls, whereas the other gilts remained group housed. At 13 mo of age, gilts were housed in clusters of three (three high-resisting or three low-resisting) for an experimental period of 7 d in climatic respiration chambers. Group-housed gilts were loose housed, and stall-housed gilts were housed in stalls within the chamber. Despite the fact that high-resisting and low-resisting gilts did not differ (P = 0.269) in initial BW, low-resisting gilts showed a higher (P = 0.039) ADG during the experimental period in association with a higher (P = 0.043) energy metabolizability. This suggests that, in line with the theory on coping strategies, high-resisting gilts may have more difficulties in adapting to a change in environment, (i.e., the change from home pen to climatic chamber). Group- and stall-housed gilts differed (P = 0.001) in initial BW, with group-housed gilts being heavier. During the experimental period, stall-housed gilts showed lower energy metabolizability (P = 0.001), lower energy retention (P = 0.001), and a higher energy requirement for maintenance (P = 0.001) due to a higher activity-related heat production (P = 0.001). This finding suggests that stall housing might have a negative influence on performance and partitioning of energy when animals are adapting to a change in their environment.

Several recent studies in juvenile pigs demonstrated a relationship between the degree of resistance displayed early in life in a so-called "backtest" and parameters of cell-mediated and humoral immunity. Some of the immune characteristics were reported to depend on the interaction between backtest classification and housing system. In the present study, the effects of backtest classification and housing condition on immune reactivity in adult gilts were examined. At 10 and 17 days of age, female piglets were subjected to the backtest. In this test, each piglet is restrained on its back for 1 min and the number of escape attempts is scored. Pigs classified as high resisting (HR) or low resisting (LR) were selected and housed in groups of six gilts. At 7 months of age, half of the gilts were housed in individual stalls. At 12 months of age, gilts were challenged by immunization with DNP-KLH. Control gilts were treated similarly with a placebo. Blood samples were drawn prior to immunization (Day 0) and weekly thereafter until Day 28. No significant effects of backtest type on cellular and humoral responses against KLH were found. Furthermore, being housed in stalls as compared to groups had no consequences for the immune response and did not induce differences between HR and LR gilts. Differences in behavior and physiology found previously between HR and LR gilts, particularly in gilts in stall housing, may thus be of relatively little importance for immune-related health.

Several recent studies on pigs have demonstrated a relationship between the degree of resistance displayed early in life in a so-called backtest and a variety of behavioural and physiological responses in piglets and young fattening pigs. To study whether pigs with diverging responses in the backtest, i.e., high-resisting (HR) and low-resisting (LR) pigs, differ also in adulthood in their responses to an acute stressor, adult nulliparous HR (n=36) and LR gilts (n=36) housed in groups or stalls were challenged by 5-min fixation with a nose sling. During the first minute of restraint, HR gilts vocalised significantly more than LR gilts. Over the whole 5-min period, HR gilts tended to vocalise more than LR gilts. Housing or backtest type did not affect immediate cortisol increase (Delta(-5 min; 15 min)). At t=45 min, cortisol concentrations in HR gilts but not in LR gilts were still higher than at t=-5 min. Heart rate quickly decreased during the first min of restraint and remained fairly constant thereafter. Estimated heart rate after 5 min of nose sling was significantly lower in HR gilts compared to LR gilts. Housing or backtest type did not affect heart rate variability indices. The results support the idea that the backtest relates to individual characteristics, which at an adult age also seem to play a role in the regulation of certain behavioral and physiological responses to short-term stress.