Observations on behaviour and skin damage of slaughter pigs and treatment during lairage.

In five Dutch and four Belgian slaughterhouses the following elements were studied: (1) slaughterhouse husbandry practice, (2) agonistic behaviour in groups of pigs, (3) indices of skin damage following slaughter recorded on a relative scale of 1–4 where 4 indicates severe damage. Variation in slaughterhouse husbandry practice was considerable (stocking density range, 1.0–3.1 pigs m−2; range of time spent in lairage prior to slaughter, 0–3 h). Brooms and/or electric goads were used to move pigs in all slaughterhouses and in one Dutch abattoir handling with sticks seemed to contribute considerably to skin damage. The level of agonistic behaviour was lowest during the first 10 min in lairage. In the Dutch slaughterhouses, large individual differences in aggression between pigs were observed. Pigs in Belgian slaughterhouses were tranquillized prior to transport, resulting in generally low levels of agonistic behaviour. The percentage of resting animals increased steadily up to an average of 36% in the Dutch abattoirs and 45% in the Belgian abattoirs after 1.5 h. In both the Dutch and the Belgian slaughterhouses, skin damage was higher in the front (2.3 ± 0.1 and 2.1 ± 0.3, respectively) and in the middle region (2.2 ± 0.2 and 2.1 ± 0.2, respectively) than in the hind region (1.7 ± 0.1 and 1.4 ± 0.2, respectively) of the pig. For the Dutch slaughterhouses, skin damage was significantly associated with time kept in lairage (P < 0.05) and with stocking density (P < 0.05). It is suggested that to decrease aggression and skin damage and thus to increase welfare in the Dutch slaughterhouses visited, stocking density should be lower and pigs should be slaughtered as soon as possible after arrival

Individual differences in aggression and physiology in peri-pubertal breeding gilts

Several recent studies on pigs have demonstrated a relationship between the degree of resistance displayed in a so-called ''backtest'' and a variety of behavioural and physiological responses in piglets and young fattening pigs. However, the discussion about the predictive power of the backtest is still going on. This study aimed at investigating the relationship between the backtest response and behaviour and physiology in peri-pubertal, i.e. nulliparous breeding gilts. During the suckling period gilts were subjected to the backtest. Piglets classified as low resisting (LR, n=36) and high resisting (HR, n=36) were selected. At 20 weeks of age they were housed in groups of six (three HR, three LR). Between 23 and 29 weeks of age, behaviour and physiology under undisturbed conditions were measured. At 26 weeks of age, LR pigs showed higher baseline salivary cortisol levels during the light period than HR pigs. However, HR and LR gilts did not differ in weight gain, aggression and heart rate response to afternoon feeding. This study indicates that when breeding gilts are kept in groups containing both HR and LR animals, aggression and heart rate reactivity under undisturbed conditions do not relate to the backtest respons