Novelty causes elevated heart rate and immune changes in pigs exposed to handling, alleys, and ramps

The objective of the present research was to quantify the cardiovascular and physiological responses in pigs subjected to novel alleys and ramps. Ten test subject pigs were selected per treatment. The first (trained) group were trained to navigate a course including a ramp. Testing was daily for seven days. Once training was completed, the trained and control (naïve) groups were exposed to a fixed course, the course and ramp (both up and down) while heart rates, time, handling difficulty, and blood were collected to determine the innate responses. Heart rates of trained pigs were reduced significantly (P = 0.003) compared to naïve pigs travelling the same course. Both handling ease and handling time were significantly improved for the trained pigs (P = 0.03 and P = 0.01 respectively) compared to naïve pigs. Blood immune measures indicated reduced stress among trained pigs who had lower neutrophil numbers (P = 0.04) and lower total and average phagocytosis (P = 0.001 and P = 0.02) compared with naïve pigs. This study demonstrated that the exposure of pigs to a novel environment clearly causes a mild physiological response. Pigs are not inherently stressed by alleys and ramps, but rather novel experiences cause handling problems and a stress response and minimal training can reduce the stress experience for the pig.