A survey of dry sow housing across England (Baynes and Hunter, 1993) indicated that 30% of producers currently with confinement systems would like to convert their existing sow buildings to conform with the ban on stall and tether systems in 1999. This study assessed the feasibility of a minimal cost conversion of part of a tether house in which the sows were liquid fed.
Sows were housed in a 21 year old tether house capable of housing 152 sows in four rows. The middle section of the house consisted of two rows of tethers, back to back, and part of this was gated off to create two pens, each capable of holding 10 sows in two rows of five. Total space allowance was 14m2/sow. Sows were of mixed weights and parities and all had previous experience of the tether house. Both groups were observed for three hours immediately after mixing, for two hours feeding on the following day, and for two hours on nine subsequent days. Eight categories of agonistic interaction (head swing with mouth closed, head swing with mouth open, push, attempted bite/slash, bite/slash, mount, vulva bite and fight of more than ten seconds), space usage and skin lesions (scored from one to five on eight regions of the body - Stewart et al, 1993) were recorded during each observation period. Sow weight and condition (scored from one to five - Whittemore, 1980) were assessed on entry to the building at four weeks post-weaning and on exit, approximately five days pre-farrowing.