Effects of food level on performance and behaviour of sows in a dynamic group-housing system with electronic feeding

Abstract

Evidence from studies of group-housed sows in unbedded systems indicates that hunger may be a cause of increased aggression between animals. The present study aimed to investigate the effects of food level on performance, aggression and skin damage in a deep-straw system. Sixteen groups offive gilts were introduced over 8 months to one of two dynamic groups in a deep-straw yard (2·35 m2 per sow) receiving different food levels from an electronic sow-feeding system: high (H: 3·0 kg and 38 MJ/day) and low (L: 1·6 kg and 20 MJ/day). Seventy second-parity sows were returned to the same treatments in the same subgroups. The behaviour of the animals was recorded throughout both pregnancies using a time sampling technique. Severity of skin damage was recorded as a number from 0 to 4 for each of nine areas, the average of which being the ‘damage score’. The total number of animals in each dynamic group was maintained at around 30, through the use of additional sows. As expected, H sows were heavier than L sows but no effect offood treatment was found on litter size or performance. L sows were more active (L v. H; standing: 41 v. 31% of total observation time respectively, F114 = 7·65, P < 0·05) and showed more straw manipulation than H sows (L v. H: 17 v. 10% respectively, F 3 34 = 18·4, P < 0·001). No differences between treatments were found either in number of aggressive interactions (L v. H: 3·6 v. 3·8 interactions per sow per observation day, F, u = 0·82, P > 0·05), or in damage score (L v. H: 0·24 v. 0·28; Flu = 0·27; P > 0·05).However, introduction of new animals did influence aggression, with sows being more involved in aggressive interactions on the day they were introduced, than on other sow's introduction days and on no introduction days (Tukey, P < 0·05). Average skin lesions per experimental sow were also higher in the days immediately following introduction. It can be concluded that in a sequential feeding system with plentiful straw, aggression is not influenced by the level offeeding. In these systems, the major factor giving rise to aggression is the introduction of new sows to the resident group.

Effects of tryptophan supplementation on aggression among group-housed gestating sows1

“…Results of the current study demonstrated that aggression among sows decreased 6 h after mixing, similar to that observed in other studies (Moor et al, 1993;Spoolder et al, 1997;Arey, 1999). No further decrease in aggression was observed among sows between 6 and 72 h after mixing.…”

“…Therefore, the effect of supplementing synthetic Trp on controlling aggression among limit-fed gestating sows in' the current study might be short-lived after feeding. Furthermore, limit-feeding increases the motivation for fighting in gestating sows (Spoolder et al, 1997), as well as in breeders of other species (Shea et al, 1990). The combination of a minimal nutrient supply and high motivation for fighting may increase the threshold of dietary "'"Means without a common superscript within a row differ {P < 0.05).°' 'Means without a common superscript within a row tend to differ {P < 0.10).…”

Animal health and welfare aspects of different housing and husbandry systems for adult breeding boars, pregnant, farrowing sows and unweaned piglets - Scientific Opinion of the Panel on Animal Health and Welfare

“…Fights aimed at determining dominance relationships generally do not last more than 1 -2 days following the mixing of unfamiliar animals (e.g. Spoolder et al, 1997;Arey and Edwards, 1998), but fights over access to feed can be a daily recurrent event, depending on the feeding method. In both situations the animals tend to develop a so called 'avoidance order' (Jensen, 1982;Jensen and Wood-Gush, 1984), which helps to minimise aggression and is closely linked to the dominance hierarchy formed.…”

“…There are several studies which have quantified the level of injuries following social interactions (e.g. Weng et al, 1998;Spoolder et al, 1997;Docking et al, 2000). These are generally based on a count or an estimation of the number of lesions, usually categorised according to seriousness.…”

“…Poor floor quality may result in increased levels of severe lesions to the hind limbs in lactating sows (Boyle et al, 1997). Edwards et al (1997) reviewed the few studies published on foot damage in lactating sows and concluded that solid concrete flooring may minimise limb lesions in lactating sows, whilst there are significant differences between different types of slatted floors mainly depending on the material they are made of, its abraisevness and the widths of slats and gaps (EFSA, 2005). They also stated that there is a conflict between optimal floor characteristics for the sow (good foothold and larger void area for cleanliness) and for the piglet (small void area and low abrasiveness).…”