Energy cost of activity (standing versus lying) in group-housed, young pigs

The effect of regrouping young pigs directly before transport on metabolic rate in relation to behaviour was evaluated. Six groups of 20 pigs were allotted to one of two treatments. In three control groups, social structure of the two original litters was not altered. In the other three groups, the two litters were mixed just before transport. After transport, energy metabolism and activity were measured per group during two weeks. Additionally video recordings were used to quantify behaviour. Heat production, corrected for activity, was 450 and 464 kJ/kg(0.75)/d for the control and mixed groups, respectively (P<0.05). On average 24.6% and 23.5% of animals were standing in the control and mixed groups, respectively (P<0.05). Energy expenditure on standing, on average 107 kJ/kg(0.75)/d, was not affected by treatment. Most of the variation in heat production related to activity could be explained by variations in energy expenditure on standing. Consequently, the contribution of agonistic behaviour while standing as well as changes in posture were negligible. Regrouping before transport had no impact on energy partitioning, but reallocation of energy expenditure between activity/behaviour and other energy demanding processes seems to occur.