Effect of partitioning pens on aggressive behavior of pigs regrouped at weaning

Two trials were conducted to evaluate the effect on agonistic behavior of a temporary partition to create a more complex pen for newly weaned, crossbred pigs. The partition, which contained two 20X30 cm ports, was placed diagonally across alternate pens within the same room. Pigs were assigned to pens by body weight. Short (<10 s) and long (greater than or equal to 10 s) fights and the number of lying pigs were quantified by direct observation for the first 3 h and again for 1 h at 24 and 48 h post-grouping. The number of scratches on each pig were counted 25 h post-grouping. The treatments did not influence aggressive behavior of the piglets. There was a significant difference (P=0.003) in agonistic behavior between the two trials. Long fights were significantly correlated with ear (P=0.05), shoulder (P=0.03) and total (P=0.03) scratches. The heavier pigs were associated with more shoulder (P=0.006) and total (P=0.04) scratches. When a fight occurred, the noncombatants frequently moved to the other side of the partition, but this was variable. No pigs were seen using corners to avoid aggression. Using a partition to make weaning pens into a more complex environment did not reduce agonistic behavior or injuries caused by agonistic behavior.