A COMPARISON OF THE WELFARE OF SOWS IN DIFFERENT HOUSING CONDITIONS

Twelve sows in good quality unstrawed stalls, three groups of five sow s in strawed pens with individual feeding stalls and sows in a 38-sow group in a strawed yard with an electronic sow feeder were compared du ring the first four parities. They originated from the same source, we re about 9 months of age and in the 7th week of their first pregnancy at the start of the experiment and were kept in adjacent rooms in a bu ilding cared for by the same staff and given the same diets at a rate of 2.2 kg/day per animal. No new animals were added to the groups or s talls during the study and animals returned to the same condition afte r periods in farrowing and service accommodation. Using a wide range o f welfare indicators, it was clear that stall-housed souls had move pr oblems than group-housed sows and that these problems were worse in th e fourth than in the first pregnancy. By the fourth pregnancy stall-ho used sows spent proportionately 0.14 of time showing activities which were clearly stereotypies and much time on activities which were somet imes stereotyped, i.e. 'drinking' and rooting or chewing at pen fittin gs making a total of proportionately 0.50 of time. Comparable figures for group-housed sows were much lower (0.037 and 0.082 in total). Stal l-housed sows were also more aggressive than group-housed by the fourt h pregnancy and their body weights were lower. There were no differenc es using physiological or immunological tests or measures of reproduct ive output. When the two group-housing systems were compared, sows in the electronic feeder system showed more fighting, especially soon aft er initial mixing, but fewer total agonistic interactions than sows in groups of five during the first pregnancy. Oral stereotypies were sli ghtly higher in small groups, perhaps because of smaller pen space, th an in larger groups but much lower than in stalls. By the fourth pregn ancy there were few differences between souls in small and large group s and all seemed to have adapted well to the conditions. Evaluation of welfare in different housing systems requires use of a wide range of measures and of long-term studies.