The Effect of Food Deprivation Length of Pair House Pigs on the Running Speed and Feeding Activity in Solitary and Social Conditions

The purpose of this experiment was to study the feeding behavior and running speed under various feed deprivation lengths and social environments. Three trials were conducted. Trial 1: ten pigs were trained individually to run a course and eat their feed at the end of the course. The pigs were deprived feed for 1, 5, 10 or 20 h. Trial 2: 1. Two pigs ran and ate together. Both pigs had 5 h of feed deprivation before the run (D5). 2. Two pigs ran and ate alone, but both pigs had 5 h of feed deprivation before the run (S5). 3. Two pigs ran and ate together. Both had 1 h of feed deprivation before the run (D1). 4. Two pigs ran and ate alone and both pigs had 1 h of feed deprivation before the run (S1). 5. Two pigs ran together, one had 5 h of feed deprivation, and the other had 1 h of feed deprivation before the run (51). Trial 3: 1. On the 1st day 5 pairs of pigs had 5 h feed deprivation and could eat feed together at (B) point (D1). 2. On the 2nd day the pigs ran and ate alone at (B) point after 5 h of feed deprivation. Feed was obtainable (D2). On the 3rd to 6th days, the pigs ran in pairs after 5 h of feed deprivation and only the dominant pig ate feed at point (B). The inferior pig was chased back to room and fed there. This stage was continued for four consecutive days, d 3 to 6. In trial 1, the running speed of pigs increased with the length of feed deprivation until 10 h, then being stable afterwards. Total feeding time increased with the length of feed deprivation (p<0.001). Eating speed did not increase with the length of feed deprivation (p>0.05). In trial 2, nine of ten pigs in treatment D5 ran faster than those in S5. Seven of the ten pigs in treatment S1 ran faster than those in treatment D1. The pigs in treatment D5 had significantly higher feed intake (p<0.001) and eating speed (p<0.05) than the pigs in other treatments. In trial 3, there were significant differences on running speed between D1 and D6 (p<0.01) and between D2 and D1, D3, D4 and D5. The inferior pig ran faster in D2 but from 3 to 6 it was the dominant pig that showed the greatest speed in completing the whole course. The results demonstrated that the pigs with low feeding motivation may cause low running speed to feed and low feed intake of the neighbor when compared with pigs kept individually.