Investigating the effect of rooting substrate provision on the group lying behaviour of pigs using machine vision

Investigating the effect of rooting substrate provision on the group lying behaviour of pigs using machine vision. By: Abozar Nasirahmadi, Sandra A Edwards, Barbara Sturm,
Conference Paper · June 2016. Conference: CIGR-AgEng Conference, Aarhus, Denmark

Abstract

To deliver good animal welfare, pigs should have a hygienic and undisturbed lying area within the pen. However, the provision of a rooting material is desirable to meet behavioural needs and this can only be given onto solid floor away from the dunging area, which might disrupt the group lying pattern. To determine whether daily provision of a rooting material (maize silage) onto a solid plate in the lying area of a fully slatted pen resulted in changed lying location, the lying patterns of pigs in 6 enriched pens were compared with those of 6 control pens which had only a suspended enrichment toy. Since visual monitoring of pig behaviours over long periods is very time consuming, an image
processing technique was applied to identify any changes pig lying positions and behaviour. Pigs were monitored by top view CCTV cameras and animals were extracted from their background using image processing algorithms. The x–y coordinates of each binary image were used for ellipse fitting algorithms to localize each pig. In order to find the lying positions, ellipse parameters were calculated for all fitted ellipses. Each pen was virtually subdivided into four zones in images and the centroid of each fitted ellipse was used for finding the position of each lying pig at 10 minute intervals during their lying period, after use of an algorithm to remove images in motion preceding the scan. By means of the ellipse properties it was possible to automatically find and compare the
changes in lying position of pigs in the pens. Results showed that once daily provision of rooting material did significantly change lying behaviour.