Implementation of a sow stance information system (SowSIS) in electronic sow feeders

Lameness in sows not only poses a health and welfare concern, but also leads to considerable economic losses for the farmer. The disease condition increases labour and treatment costs and leads to premature culling and euthanasia of sows. Since the obligation to house sows in groups in the European Union in 2013, an increase in lameness prevalence is seen. It is therefore essential that lameness is detected accurately and at an early stage. Visual detection of lameness is a subjective technique, usually only detecting severe lameness cases. Visual detection of lameness becomes even more difficult due to the group-housing of sows and the increase in farm size. Recently, at ILVO SowSIS (Sow Stance Information System) was designed and validated for objective lameness detection in sows. SowSIS performs automatic force measurements and additionally generates visual stance variables using a transportable device with four load cells (one for each leg of the sow) and a camera arm. A sow is guided into the device and the force exerted by each of the four legs is measured. Using the camera, a lateral digital image can be taken of the hind legs. An adapted version of the SowSIS system has now been implemented in four electronic sow feeders (ESF), using only the force stance variables. The aim is to validate this adapted system for individual online and repeated measurements of group-housed sows, without interfering with their daily routine. A trigger is used to start the measurements automatically while a sow is feeding. The sow is automatically identified at the trough. Due to the asymmetric design of the ESF (feed trough in the left or right front corner of the ESF), a correction for the uneven balance of the sow is necessary. Measurements are performed in four pens on ILVO’s experimental farm. Sows will be followed-up throughout time to validate the adapted system and its ability to detect changes in the force stance variables related to lameness development. When the system has been validated, the automatically gathered data can be used to signal the farmer when a lameness case is arising. The SowSIS implementation in ESF thus aims at early detection of lameness cases and possible prevention of economic losses.