Are tethered sows stressed? A behavioural comparison of tethered and loose sows

81 proposed that “open-field behaviour in chickens merely represents a compromise between opposing tendencies to reinstate contact with conspecifics and to minimize detection in the face of possible predation”. They further suggested, albeit indirectly, that the open field does not measure fear. However, rather than inhibiting vocalization and ambulation by diminishing the reinstatement tendency and increasing predator evasion, as Gallup and Suarez predicted, the presence of companions in the open field promoted activity and vocalization. The fear hypothesis would, of course, predict such a finding, because both separation distress and the novelty value of the open field would be reduced by the presence of familiar companions. Gallup and Suarez also predicted that individually-housed birds would take longer to peep and walk than group-reared chicks when tested individually in the open field, because their reinstatement tendency would be weaker and, hence, their predator-evasion reaction dominant. However, the fear hypothesis would predict the opposite results, because isolates would be expected to experience less separation distress. The present finding that individually-reared birds froze less and peeped and walked sooner than groupreared chicks is, therefore, consistent with an interpretation based on fear. In conclusion, the present results contrast with those predicted and reported by Gallup and Suarez. They are consistent with other results and they conform to the fear hypothesis. Thus, while the opposing tendencies of reinstatement and predator-evasion are probably important in many situations, there is considerable evidence for the role of fear in regulating open-field behaviour, at least in the domestic chick.

REFERENCE Gallup, G.G. and Suarez, S.D., 1980. An ethological analysis of open-field behaviour in chickens. Anim. Behav., 28: 368-378.

ARE TETHERED SOWS STRESSED? OF TETHERED AND LOOSE SOWS

A BEHAVIOURAL

COMPARISON

K. VESTERGAARD Department of Forensic and State Veterinary Medicine, Royal Veterinary and Agricultural University, Copenhagen (Denmark)

ABSTRACT Although tethering sows may be laboursaving and allow more animals to be kept in a unit area, there may also be a number of disadvantages. Some of the better-known problems include neck injuries caused by the collar, delayed puberty, irregular oestrus and difficulty of detecting oestrus by the herdsman. In addition, tethering may have a number of other unwanted consequences for the animal, such as “poor condition” and the occurrence of frustration due either to the lack of appropriate releasing stimuli in the environment or to the prevention of the performance of essential behaviour patterns. As a result, we might expect abnormal behaviour to appear. The present study was designed to evaluate the effects of tethering either during pregnancy, or during the farrowing-lactation period, or throughout the whole period. Several

82 control groups of loose-housed sows at different densities were kept in the same building. All animals were given straw. Behaviour was observed directly and also recorded by means of time-lapse film and video-tape. The tethered sows showed the same diurnal activity rhythm as the loose sows, but their activity was reduced and this effect was more evident during pregnancy than during the farrowing-lactation period. The loose pregnant sows tended to alter their lying posture according to ambient temperature, whereas the tethered sows stood more as temperature rose. In the loose sows, rubbing behaviour directed towards housing structures was unaffected by temperature. In the tethered sows, however, rubbing behaviour increased with temperature, and this, together with the increased time spent standing, was interpreted as an inappropriate attempt to cope with high temperatures. Tethered sows showed about the same amount of aggression but much more stereotyped behaviour than the most crowded loose sows. During the last 24 h before farrowing, the tethered sows showed much restlessness and chain-pulling, which was interpreted as thwarted nesting behaviour. Tethering during pregnancy and/or during the farrowing-lactation period resulted in increased duration of farrowing.

THE WELL-BEING OF SOWS KEPT IN DIFFERENT INDIVIDUAL HOUSING

SYSTEMS

OF

R. DE KONING Research Institute for Animal Husbandry,

“Schoonoord

“, Zeist (The Netherlands)

ABSTRACT Five thousand dry sows, kept in stalls or tethered by the neck (both collar and harness) or chest, were inspected to determine their well-being and to find out if epidemiological techniques could be used to assess welfare within a reasonable time. Ekesbo (1973) used epidemiological techniques to study the relationships occurring between housing, production and health in cattle and pigs. In these studies, the level of skin lesions was used as a parameter for well-being. When implementing this method, all lesions have to be listed according to site and nature. An inspection routine has then to be developed by selection of a number of representative sites from all over the body, and by classification and evaluation of lesions according to a scoring system. The total level of lesions of animals is a parameter for their well-being. The total level of lesions in sows tethered by neckcollars was higher than that of sows kept in stalls tethered by a shoulder girth or neck-harness. Therefore, it was concluded that when the sows are used to the housing system, there is not much difference in wellbeing in the latter three systems, but the well-being is lower when the animals are tethered by neckcollars. The level of lesions of the udder was low when sows were kept in stalls or tethered by neck-harness, but high when they were fixed by shoulder girths. A shoulder girth apparently hampers the sow in getting up. Tethers for sows can be fixed to the floor or to the partitions between the stalls. According to the level of lesions, floor fixtures should be preferred both for neck tethering and for chest tethering. Habituation to an individual housing system seemed to be easier in stalls than when sows were tethered. The level of lesions on the neck of sows tethered for the first time by neck-harness showed a peak at 10 days after tethering, followed by a steady decrease. It