Effects of exposing pigs to moving and odors in a simulated slaughter chute

Pigs in the finishing stage are infrequently handled and can be difficult to handle when experiencing novel situations. This study sought to determine the effects of minimal training and a novel odor/taste reward on the ease of handling finishing pigs in a novel environment. Pigs were assigned to one of four treatments organized in a factorial arrangement: training and odor exposure at the barn or not (trained or non-trained, respectively) and provision or not of maple syrup in the simulated pre-stun area of a slaughter plant (reward or no reward, respectively). Trained pigs (n = 14 pens) were let out of their home pens and onto a trailer for 10 min/d for 10 d and could chew on maple syrup-soaked flags. Non-trained pigs (n = 14 pens) were not handled or exposed to maple syrup. After the 10 d, trained and non-trained pigs were transported, unloaded and then experienced a novel simulated pre-stun area. A maple syrup-soaked flag (reward) was dragged through the simulated pre-stun area and put in a simulated CO2 stun box. Non-rewarded pigs were not exposed to maple syrup. Trained pigs unloaded the trailer and reached the resting pen faster (P = 0.014) than non-trained pigs. Trained pigs had fewer (P = 0.02) blood neutrophils and more (P = 0.03) lymphocytes than non-trained pigs. Rewarded pigs received fewer (P = 0.02) taps before reaching the simulated CO2 stun box than non-rewarded pigs. Cortisol concentration increased (P = 0.004) when the total time to reach the simulated CO2 stun box increased. Pigs that were allowed to exercise out of their home pen and were given access to an odor/taste reward moved faster and the neutrophil:lymphocyte ratio was decreased when exposed to a novel environment containing the same odor/taste reward.