THE EFFECT OF KEEPING FATTENING PIGS IN GROUPS ON FULLY SLATTED FLOORAND IN DANISH BOXES WITH STRAW LITTER AT DIFFERENT ENVIRONMENTAL TEMPERATURES ON GROWTH-RATE, FOOD CONVERSION AND CARCASS QUALITY

Within seven replications 220 fattening pigs were kept in two separate d rooms prepared for different thermal conditions, one of them heated to about 20-degrees-C at the beginning with the temperature gradually declining to 15-degrees-C; the other one not heated during the winter replications with temperatures of about 12 to 15-degrees-C at the begi nning, then declining to 8 to 13-degrees-C within a few weeks with nat urally fluctuating circadian sinusoidal variations, minimal temperatur es going down sometimes to 3-degrees-C. In each room two different box es for eight pigs were installed. One box had a fully slatted floor, t he other one being a type of danish box with a resting area being litt ered by chopped straw (0.2 kg/pig and day). The animals were fed restr ictively, metabolizable energy supply was 1.47 MJ/kg W'' at 25 kg life weight gradually declining to 1,13 MJ/kg W'' at 100 kg (W'' = metaboli cal weight = kg0.75). The food supply of the pigs in the cold housed g roup with straw was 11 % (0.2 kg/day) less than that of the other anim als due to a malfunction of the feeding station not detected by the co ntrol PC and not perceived on time. The following tabel 1 shows the ma in results: [GRAPHICS] Daily gain of the warm housed pigs with straw l itter was 45 g higher compared with the animals on slatted floor at sa me temperatures. In the cold room this difference was even 97 g. The m ean superiority of the littered boxes over the year was 72 g. With 11 % less food intake, the cold housed pigs with straw showed same daily gain, same length of fattening period and slightly better food convers ion than warm housed animals on slatted floor. Straw has various benef icial effects not only thermal ones. There were no differences between the groups at most of the criteria of carcass quality except the perc entage of loin area, which was significantly smaller in the pigs house d cold on slatter floor. Alls pigs on slatted floors had significantly shorter body lengths than those with straw probably caused by unnorma l lying behaviour on the belly. Pigs on slatted floors showed a signif icant higher frequency of technopathies, especially alterations of joi nts (lamness) and injuries of the integument. Better growth rates of a nimals kept with straw, the possibility to avoid heating costs and new housing systems which need very small amounts of straw, e. g. ''straw -flow-systems'' or systems with closed nest boxes, give the possibilit y to combine welfare aspects of the pigs with economic improvement of production.