A Sow-Welfare-Optimized-Feeding (SWOF) system with group-adapted ad libitum liquid feeding was developed to ensure that both optimal nutritional and behavioral needs are met in group-housed pregnant sows. This system comprises functional areas and allows sows to have either a low- or high-energy diet according to their current weight in relation to their parity. This field study aimed to investigate how this new system influences sows’ body weight, health status (lameness), aggression parameters (integument injuries, vulva injuries, and displacements at the trough), feed intake rhythm, and litter performance. In parallel, these parameters were also recorded in the existing system (group-housed sows restrictively fed a dry diet). In the SWOF system, the probability of displacements at the trough and occurrence of vulva injuries were reduced, whereas sows could follow a natural biphasic feed intake rhythm. Though lameness scores and litter performance were not affected, lower body weights and more integument injuries were, however, observed. Yet, results can only partially be attributed to the feeding system per se due to confounding effects such as management practices and group size differences (larger dynamic group vs. stable group). Hence, the SWOF system seems promising with regard to animal welfare but remains to be further validated.

When feeding pregnant sows, optimal body condition at birth is sought to avoid the effects of a deviant nutritional condition on health and performance. Various feeding concepts exist but mainly have a restriction in quantity and renunciation of farm-grown forage in common. An ad libitum liquid feeding system based on farm-grown forage in combination with a sow sorting gate (according to body weight—using mechanical scales) was realized on a commercial swine farm. The sorting gate coordinated access to two feeding areas with rations based on whole plant wheat-silage (WPWS) differing in energy content. In this study with a total of 183 pregnant sows, effects of restrictive dry feeding (System I) were compared with ad libitum liquid feeding based on farm-grown forage (System II). Sows were monitored regarding body condition development during pregnancy by measuring body condition score (BCS), body weight (BW), and back fat thickness (BFT) on different time points. Sow and piglet health (vaginal injuries of sows, rectal temperature during the peripartal period, vitality of newborn piglets) and performance data regarding litter characteristics were also recorded. Body condition development of the sows was absolutely comparable. Performance indicators and the course of birth were also similar but with significantly higher scores for piglet vitality in System II (p < 0.05). The tested concept offers opportunities for more animal welfare and sustainability but remains to be further investigated regarding the repertoire of possibly applied farm-grown forage and the effects of the concept in the transit phase of sows.

BackgroundCommon feeding systems for pregnant group-housed sows meet the nutritional demand but do not sufficiently consider their natural feeding behavior. A new group-adapted ad libitum feeding system called “SWOF” (Hölscher + Leuschner GmbH & Co. KG®, Emsbüren, Germany) was developed to ensure that both optimal nutritional and behavioral needs are met. This feeding system comprises an activity and lying area and two areas with ad libitum liquid feeding on the basis of whole plant wheat silage. Passing through a sorting gate, sows could be given either a low- or high-energy diet according to their weight and parity. The study’s aim was to investigate the effects of this new system on sows’ body weight, health status (lameness), aggression parameters (integument injuries, vulva injuries, displacements at the trough), feed intake rhythm, and litter performance, and to compare these with restrictively fed group-housed sows, which is the common standard in Germany. ResultsIn the group-adapted ad libitum feeding system, significantly less risk for displacements at the trough and vulva injuries were observed, and sows followed their natural biphasic feed intake rhythm. This system also resulted in lower body weight and more integument injuries than the restrictively fed group-housed sows. However, these might be due to different management practices and group size between the two systems. No influence of the feeding system was observed, neither on lameness nor litter performance. ConclusionThe data reported here show the promising effects of the group-adapted ad libitum “SWOF” feeding system with regard to animal welfare, as sows can freely choose when and how much feed they want to consume without taking the risk of over conditioning. The “SWOF” feeding system remains to be further validated, also considering the group size and management practices.