Shackling of commercial poultry involves the insertion of each leg into parallel metal slots and holding the bird inverted for a period of time before stunning and slaughter. Nociceptors signalling noxious stimulation of the skin have been identified in the beak and feathered skin but not in the scaly skin of the leg. The physiological properties of the C-fibre mechanothermal (CMT) nociceptors in the skin over the tarsometatarsus in the lower leg were studied in response to quantitative mechanical stimulation. The electrical activity was recorded from single C-fibres dissected from the parafibular nerve in anaesthetized animals. The receptive fields of these receptors were small and spot-like, measuring in the region of 1-3 mm in diameter. The threshold to mechanical stimuli ranged from 0.8-15 g using von Frey filaments, and from 3-33 g using a 0.5mm probe mounted on a feedback-controlled stimulator. Stimulus response curves using a ramp-and-hold stimulus were recorded for a number of fibres. After comparing these threshold measurements and the stimulus response data with previous measurements of the force applied to the legs during shackling, it was concluded that shackling is likely to be a very painful procedure.

The effect of degree of isolation on the behaviour of weaned piglets was investigated using eight replicates of littermates, weaned at 4 weeks and caged for 2 weeks in metabolism chambers under varying degrees of isolation: i) fully isolated without physical contact with littermates; ii) partly isolated with limited physical contact with littermates; or iii) grouped with three littermates. The behaviour of the piglets was video recorded from 0700h-2230h on days 1, 6 and 13 post-weaning. In addition, a test of behavioural reactivity towards a novel environment/object was performed on day 8.

Irrespective of degree, isolation initially increased the occurrence of behavioural indicators of stress such as the frequency of pawing and escape attempts as well as decreasing the frequency of play. In partly isolated piglets this initial response was more active than in fully isolated piglets, indicating an increased frustration with isolation. Within 2 weeks, however, the stress response in partly isolated piglets had almost completely waned, and they showed only a decreased frequency of play behaviour, whereas in fully isolated piglets an increased frequency of pawing as well as a more pronounced reduction of play behaviour were still evident on day 13. Both isolation treatments resulted in markedly lower reactivity in a novel environment, seen as fewer squares crossed and fewer vocalizations.

It is concluded that social isolation of newly weaned piglets is stressful. Although it may increase the initial stress response, provision of social contact with littermates, eg through wire mesh, might limit negative long-term effects of isolation in experiments where data collection requires individual housing.

Finding a responsible method of population control that does not compromise animal welfare is a pressing problem for zoological institutions and conservation breeding programmes. This is exemplified by the conservation breeding programme of the golden-headed lion tamarin, Leontopithecus chrysomelas. The number of golden-headed lion tamarins in captivity is currently being limited by, among other means, the use of contraception. We have conducted a study on the effects of contraceptive methods used in golden-headed lion tamarins. Data were collected through the distribution of a survey. The use of Melengestrol acetate (MGA) implants in females was by far the most widespread contraceptive method. It was very effective in preventing reproduction, provided that females were not pregnant at the time of implantation. Pregnancies that had commenced before MGA implantation were carried to term and resulted in viable infants, as far as noted. However, the degree of reversibility was very low and, if females did conceive after MGA implantation, infant survival was lower than expected. The widespread use of MGA implants in golden-headed lion tamarins (and probably other species) should be seriously reconsidered. Alternative methods of population control should be investigated. Possible options include the use of other contraceptive methods, limiting the number of offspring through natural factors and the use of euthanasia under very strict conditions. Animal welfare implications associated with the use of euthanasia are discussed.

The within-farm prevalence of vulva biting in breeding sows in south-west England was investigated using a postal survey sent to 410 pig farmers in January 1997. The response rate was 65 per cent and there were 83 useable replies. The majority of farms where vulva biting was reported indicated a low within-farm prevalence of 1-9 per cent of sows affected, although prevalences as high as 30-60 per cent were reported. The injuries reported ranged from bleeding to removal of the whole vulva, the most commonly reported injuries being bleeding and superficial damage to the vulva. No long-term effects from this injury to service and dry sows were reported by 70 per cent and 76 per cent of farmers respectively. Competition for food, aggressive sows, closeness to farrowing and mixing of sows were the most common reasons suggested by these farmers as causes of vulva biting.

Group housing of male laboratory mice often leads to welfare problems due to aggressive behaviour. From a welfare perspective, individual housing is not a preferred solution to these problems - and so we sought other ways of reducing aggression between male mice. Aggression peaks after disturbances such as cage cleaning. Transfer of olfactory cues during cage cleaning procedures has been repeatedly proposed as a means of reducing these peaks in aggression. In this study, the aggression-modulating properties of olfactory cues were studied by investigating the effects of their source and distribution on aggression after cage cleaning in groups of male BALB/c mice. The physiological effects of aggression on individuals within a group were also monitored.

Our results indicated that neither kinship nor distribution of urine marks affected aggression. Olfactory cues from nesting and bedding material, however, affected aggression to a marked degree: transfer of nesting material reduced aggression significantly, while transfer of sawdust containing urine and faeces seemed to intensify aggression. None of the physiological data revealed any differences between dominant and subordinate animals, nor any correlations with aggressiveness, except that dominant animals gained weight more rapidly than subordinate ones. We conclude that the transfer of nesting material will reduce aggression, or at least slow down its development, and thus aid the reduction of social tension due to cage cleaning.

The social environment is very important for the welfare of animals in loose housing dairy production systems. This article reviews recent literature on the effect of animal density (AD) and regrouping (RG'j on the welfare of cattle and describes the development of feasible indicators for the social environment. Special emphasis is given to the methodological problems that arise when AD and RG are used as welfare indicators in a welfare assessment at the herd level. Various factors affecting estimates of AD were considered, including the size of the animals, correction for very high AD values, pen shape and how best to aggregate the results at herd level and over time. The examination of RG is centred around the effect of early social experience of the animals, the stability of social relationships, and the effect of pen changes.

A range of parameters is suggested for the evaluation of AD and RG as possible welfare indicators. These are based on observational data from 10 Danish dairy herds and related to clinical records from the herd farms. It is concluded that mean AD is not feasible as a welfare indicator at the herd level but the 25th percentile of AD corrected for the liveweight of the animals should be used instead. The two most promising parameters for evaluation of RG are the frequency of combined pen and group changes for a sample of the herd, and the probability of a certain duration of inter-animal relationships. Results from clinical observations correlated with neither AD nor RG.

The post-release survival of hand-reared tawny owls, Strix aluco, was studied. Hand-rearing did not appear to affect the birds’ instinctive behaviour or post-release survival. The recovery of several pellets confirmed that hunting in this species is an innate process. In terms of animal welfare, hand-reared tawny owls do not appear to be at a disadvantage when compared with wild juveniles, indicating that current rearing and release practices are effective.