An investigation of a novel behavioural test to assess pain in piglets following castration

A novel behavioural test using a handling chute was evaluated over two trials as an objective method to assess pain in piglets following castration. Piglet (n = 98) navigation time (NT) through a handling chute was measured at specific time points up to 24 h post treatment. In trial 1, comparing the NT of castrates (C) and sham castrates (SC), C piglets had a longer NT than SC at 0 and 15 min post treatment (P < 0.05), with no differences thereafter. In trial 2, the effect of an analgesic to control postoperative pain on NT was examined, with castrated piglets given a half (CH) or full (CF) dose of meloxicam 1 h prior to treatment, compared with piglets castrated and given saline (CS) or sham castrated and given saline (SS). Post treatment, CS piglets had a longer NT than SS at 0 min (P < 0.005), and at 15 min, piglets CS had a longer NT than all groups (P < 0.001). No significant associations were found between piglet behaviour in the home pen and NT during the 60 min following treatment. These data demonstrate potential for the use of a handling chute to measure NT as a quick, standardized, method to assess piglet pain in response to castration.