Simulation of loading and unloading through ramps of different configuration: effects on the ease of handling and physiological response of pigs of two slaughter weights

Behaviour, heart rate (HR) and blood lactate concentration of 144 pigs, equally distributed into lighter (L, 122 kg on average) and heavier (H, 153 kg on average) groups, were assessed to study the effects of slaughter weight on pigs’ response to a simulated loading and unloading procedure using four ramp configurations, i.e., 0º (level ramp), 15º slope and 1.66 m length, 15º slope and 2.71 m length (15ºLO), and 25º slope and 1.66 m. No interaction was found between ramp configuration and slaughter weight (P > 0.10). The frequencies of pigs’ slips or falls (P = 0.01) increased on sloped ramps compared to the floor level (Padj < 0.05), and pigs jumped-off more from the 25° than the 15°LO ramp (Padj = 0.05). Pigs negotiating the 25° slope ramp presented a higher concentration of blood lactate than those walking at the floor level (P = 0.02). When compared to L pigs, H pigs were more reluctant to move (P = 0.05) and, presented higher increments of HR (ΔHR) during handling (P = 0.03). In conclusion, heavier pigs were more difficult to handle, regardless of the ramp steepness, which alone reduced ease of handling and affected the physiological condition of pigs.