AbstractIn order to reduce ammonia emissions from pig housing systems, the Council of Europe proposes the use of part slatted flooring in preference to fully slatted flooring, but the effects of such changes on the health and welfare of pigs in the UK has not been defined. The aim of this experiment was to investigate the effects of different floor types on the emission of ammonia, behaviour and welfare, physical performance and respiratory and enteric health of growing/finishing pigs. This involved three replications of five treatments: 1) UK fully-slatted, 2) UK fully–slatted with rubber matting over 50% of the slats, 3) UK fully–slatted with “structural” modifications which involved “paving” over 50% of the floor and partitioning off the slurry channel beneath the solid floor, 4) UK part–slatted, and 5) novel Dutch partslatted with UK pig stocking density. Groups of 10 pigs (balanced for gender) weighing approximately 40kg were on–test for 10 weeks.