GROWTH-PERFORMANCE, CARCASS COMPOSITION AND LEG WEAKNESS IN PIGS EXPOSED TO DIFFERENT LEVELS OF PHYSICAL-ACTIVITY

In order to evaluate the effect of exercise training and spontaneous p hysical activity on growth performance, cal cass composition, and loco motory ability 48 female and 48 entire male pigs were subjected to one of three treatments: individual housing in pens of 2.5 m(2) (confined C), individual housing and treadmill training for 15 min/day at a spe ed of 4 km/h, 5 days/week for a period of 70 days (trained; T) and gro up-housing equal to 0.9 m(2) per animal (free; F). Pigs in treatment C and T did not differ with regard to daily gain, food intake, kg food per kg gain and carcass lean content. Training did, however, induce si gnificant cardiac hypertrophy (by a proportion of 0.06). In treatment F (i.e. large pens), daily gain was 135 g lower than in treatment C. D issection of the carcasses showed that treatment F increased the weigh t of m. psoas major (by 30 g) and the total carcass bone mass (by 130 g) when compared with treatment C. Proportions of carcass lean and int ramuscular fat were unaffected by treatment F. Likewise, leg weakness and osteochondrosis did not differ between treatments, whereas the loc omotory ability was positively affected by rearing in large pens (trea tment F) but not by treadmill training (treatment T). Thus, physical a ctivity in large pens induced various adaptations throughout the body.