Zum Einfluss des Tier-Fressplatz-Verhältnisses in der Gruppenhaltung tragender Sauen bei ad libitum Fütterung auf Gesundheit, Verhalten und Leistung

Abstract. Title of the paper: Influence of animal/feeder-trough space ratio on health, behaviour and performance of group housed sows fed ad libitum
The EU-Directive on the "Minimum requirements for the protection of pigs" prohibits the housing of gestating sows in individual crates. One alternative to individual housing of restricted fed sows is group-housing with ad libitum access to feed. The proposed animal/feeder-trough space ratio of 4:1 in the German legislation was taken from housing systems for growing pigs due to a lack of scientific data on sow to feeder-trough space ratios. The aim of this study was to evaluate practically meaningful animal/feeder-trough space ratios with respect to animal welfare. Therefore, different animal/feeder-trough space ratios between 8:1 and 20:1 were investigated on three farms. The behaviour at the feeder, as well as health (body scoring), weight gain, back fat thickness and fertility were recorded in gestating sows between days 35 and 110 of pregnancy. The frequency of aggressive interactions and displacements at the feeder was progressively reduced in all tests after grouping the sows. Furthermore, the results pointed out that narrowing the animal/feeder-trough space ratio positively influenced both the conditioning of the sows before lactation and birth weights of the piglets. No clear trend between the different animal/feeder-trough space ratios of group-housed sows was found for the total number born, live and dead born piglets. A small number of sows showed minor injuries, which are not unusual for group housing systems. The evaluated animal/feeder-trough space ratios did not show indications of an impaired well-being of the sows. Our data do not support the legal demand for a threshold of 4:1 for the animal/feeder-trough space ratio. However, further studies with varying group sizes, group densities and animal/feeder-trough space ratios are needed in order to provide detailed recommendations on acceptable ratios.