Abstract:
Proc. Aust. Soc. Anim. Prod. Vol. 16 THE BEHAVIOUR OF TETHERED SOWS WHEN GIVEN THE OPPORTUNITY TO EXERCISE JUDITH K. BLACKSHAW* and J.F. McVEIGH** SUMMARY In individual housing systems for sows, the lack of opportunity to exercise has been raised as a welfare issue. In this study 18 sows were kept in neck tethers for 11 weeks over their gestation period until they were due to farrow. Half of these sows were given the opportunity to exercise three times a week for 5% h between feeding periods. Behavioural observations showed that the exercise pigs marked and explored the pen, behaviours which are not seen in tethered pigs. Also the exercise pigs rested significantly sooner after feeding than the tethered control sows, As pregnancy advanced both the control and exercise groups lay down significantly sooner after feeding. Reproductive data (piglets born alive and dead) were not significantly different in either system. Even when given the opportunity to exercise, the sows preferred to rest once they had marked and explored their environment; so provision of an exercise area for domestic sows does not ensure they will use it. (Key words: sow, behaviour, exercise.) INTRODUCTION The welfare of sows housed individually in intensive husbandry systems is currently under discussion, and one concern is the lack of exercise for the animals in these systems. Activity patterns of wild pigs are dependent on the environmental conditions, predator pressure and food availability (Graves 1984). There is no reason to suggest that adult pigs exercise, unless they are seeking food, sexual contact, shelter or water. These needs have been eliminated in modern intensive piggery systems and it is debatable whether exercise is necessary for the welfare of these animals. Several studies indicated that sows either forced to exercise during gestation (Hale et al. 1981), or given the space to exercise (Parry 1983) have the same reproductive performance in terms of piglet viability, numbers of pigs farrowed and weaned, birth and weaning weights, as similar unexercised animals. Also the gestation length was not affected by exercise (Hale et al. 1981). A reported abstract on the exercise needs for tethered and free moving sows (Gravzs 1981) indicated that there was a significant difference in still-born piglets per litter for the free-moving (0.7) and tethered sows (0.1). He suggested that tethering of sows may have the potential for increasing productivity by a reduction of still-born young. In 1965, Haugse et al. r ecorded data collect ed over three yea rs on the activities of pigs housed in a barn with access to an out side area. They spent * Department of Animal Production, University of Queensland, St Lucia, Qld. 4067. ** Veterinary Science Farm, University of Queensland, Pinjarra Hills, Qld. 4069. 147 Proc. Aust. Soc. Anim. Prod. Vol. I6 80 - 85 percent of the day resting, 9.6 - 12.6 percent feeding (depending on whether the food was pelleted or meal), and 7.4 - 8.6 percent in other activities including drinking, walking, playing or fighting. Work of Lambert et al. (1983) indicated that in five different intensive systems (group housing fed automatically, in individual stalls or on the floor, and individually housed pigs in stalls or tethers) the time spent lying over 24 h was similar in all systems (0.79 of total time). There were considerable differences between the * systems in exploratory behaviour (sows nosing, biting or licking bars, floors or pen) with individually housed sows having the highest incidence of this type of activity (0.078 vs. 0.016, P < 0.001). Barnett et a1.(1985) found that resting behaviour occupied 76.7-91.1 percent of total behaviours and that tethered pigs spent more time resting than pigs in stalls grouped indoors or grouped in a paddock. Unlike the observations of Lambert et al.(1983) oral-nasal behaviours occurred in similar amounts in all treatments. This study was desi.gned to determi.ne the behaviour of tethered sows when given the opportunity to exert ise during gestation. MATERIALS AND METHODS The study was carried out in a 55 sow, specific pathogen free piggery at the Veterinary Science Farm, University of Queensland, Australia. The sows were Large White X Landrace stock individually housed in neck tethers, on concrete, throughout pregnancy. Sows are moved from the mating area into the tethers 4 weeks after mating and remain there for 11 weeks before reaching the farrowing area about 1 week before parturitiyn. Litter data are recorded. The tether system provided 1.04 m /pig but the 65 cm chain allowed each pig 3.0 lL2* The sows were all in their second parity and were fed commercial pellets twice a day (lkg twice/day) at 0700-0730 and 1330-1400. The sows given the opportunity to exercise were released from their neck tethers immediately after their morning feed three times a week, and each sow was run into a wire mesh pen 4.6 m x 1.6 m with 1 m sides and a concrete floor. The sows were returned to their tethers before the afternoon feed, so remained in the pen about 5% h. The exercise treatment contained 3 replicates over time with 3 sows in each replicate, and the control treatment also contained 3 replicates over time with 3 sows in each replicate. The experiment was over 9 months excluding the winter period. Observations. During the first two exercise periods, observations were taken continuously for one hour and the control group sampled each 10 minutes. For the remaining time the behaviour of sows in both groups was recorded each 15 minutes. Observations were made on those behaviours presented in Table 1. These behaviours are the most common in tethered sows (Blackshaw and McVeigh 1984, 1984/5). A detailed observation (continuous recording for 1% h) was taken each week over the 11 weeks the pigs were exercising and on the last day before the sow was placed in the farrowing crate. RESULTS Both the control and exercise sows, when in tethers, showed behaviours of stand, stand and chew, stand and lick trough, sit, sit and chew and lie, and these are similar to those reported previously by Blackshaw and McVeigh (1984/85). There was a much more varied repetoire of behaviours shown by the exercise sows when in the pen, which included behaviours which may be regarded as exploratory (marking the pen with the side of face and body, galloping, snout 148 Proc. Aust. Soc. Anim. Prod. Vol. 16 Table 1 The behaviours of all exercise sows in proportions of these behaviours of the behaviours over time is shown (week 1, week 11, the last observation). Means the exercise pen; the total number of observed two observations a & b, and are also shown Table 2 The time taken for the control sows in tethers and the exercise sows in the exercise pens to lie down on Day 1 and the final day before being put into the farrowing crate (3 sows/group) 149 Proc. Aust. Soc. Anim. Prod. Vol. 16 rubbing, sniffing and walking). These activity patterns are shown in Table 1. Once the exercise and control pigs lay down they did not move until the next feeding period. Galloping behaviour was quite spectacular in the first week and lasted 2-3 minutes, but was absent by the last observation. Resting behaviour is shown in Table 2 for both control and exercise replicates. Analysis of variance showed that the tethered, control pigs took significantly longer to lie down after feeding than the exercise pigs (P < O.Ol), and, this decreased from the first observation to the day before the sows were placed in the farrowing crate (P < 0.01). The standard deviations in Table 2 indicate that the pigs in tethers tended to lie down within a much shorter time range of each other than the exercise pigs. The tethered pigs were side by side in tethers, and when they rested they always touched each other. The averag e numb er of piglets born alive (9.1 vs. 8 8) 0 r dead (2.1 vs. 1.3) Per sow did not d iffer for the cant rols 0 r exert ised sows DISCUSSION It would seem that even when given the opportunity to exercise, sows tend to prefer resting once they have marked and explored their environment. Both the control and exercise groups lay down sooner after feeding as pregnancy advanced which would be expected. Also the activity patterns of both the exercise and control sows when in tethers was similar. Social facilitation may have influenced the tethered sows to lie down within a shorter time range of each other than the exercise sows who were further apart and could not touch each other. Although the sample size was small, there was no obvious tendency for stillbirth rate to be affected. It is always difficult to assess the needs or requirements of animals on the basis of behavioural change. It could be argued that the decreased activity of the exercise sows may indicate that their motivation to explore the pen has been satisfied, and that increased activity by the control sows may indicate some difficulties in coping with the housing system. Also environmental differences may produce behavioural changes. Provision of an exercise pen does not ensure that it is used for exercise. REFERENCES J.L., WINFIELD, CM., CRONIN, G.M., HEMSWORTH, P.H., and DEWAR, A.M. (1985). Appl. Anim. Behav. 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