Current educational literature based on experience suggests that moving pigs in small group sizes is preferred because pigs may experience less stress. This study sought to determine the optimal group size of pigs in a simulated move from home pens to a transport vehicle. Group sizes of pigs ranging from 1 to 10 pigs/group were handled through a standard handling course. During handling, cardiovascular responses, time, and handling measures were collected. Group size significantly influenced heart rate. As group size was increased, a linear increase (P < 0.05) in heart rate was observed. As group size increased, handling difficulty and time to complete the course increased (P < 0.05). Models calculated the total time required to load a simulated livestock trailer containing 170 pigs. The total time required to load a truck was similar (P > 0.10) when ten pigs were moved at a time as when 5 or 6 pigs were moved at a time. Moving pigs in groups of 5 or 6 caused less (P < 0.05) elevation of a heart rate than when pigs of larger group sizes were moved. Considering heart rate elevation and time to load a livestock trailer, moving 5 or 6 pigs at a time was optimum for both time savings and the least elevation of pig heart rate during handling.
- Group size