Footpad dermatitis and pain assessment in turkey poults using analgesia and objective gait analysis.

The relationships between litter moisture, footpad dermatitis (FPD) and pain in medium-heavy turkey strains was studied by gait analysis in two medium-heavy with and without analgesia (betamethasone or bupivacaine). The relationship between FPD and litter moisture was linear above a breakpoint of 49% litter moisture, and there were no differences between the two breeds in susceptibility to FPD. Gait analysis showed higher impulse, single support time, stride time and stance time in breed A compared to breed B. Significant interactions between breed, litter and analgesic for impulse, single support time and stride time were associated with higher means for breed A given saline injection on wet litter. Data from betamethasone analgesia in Experiments 1 and 3 were combined for analysis. Peak vertical force was higher in saline- compared to betamethasone-treated birds. Compared to the wet (high FPD) litter treatments, birds on dry (low FPD) litter had greater speed and lower double support time and longer stride length. Turkeys kept on wet litter had a longer stride length compared to dry litter when given saline, whereas in betamethasone-treated birds the means were similar. There were no differences between birds with or without bupivacaine analgesia. Peak vertical force was higher in breed A than B and in birds with a low FPD compared to a high FPD score. It was concluded that breeds A and B did not differ in susceptibility to develop FPD when housed on wet litter but may have natural gait differences. Significant changes in gait parameters were associated with wet litter and with analgesic treatments. The results showed that FPD affected the gait of the turkeys and, combined with evidence of behavioural changes when given analgesia, suggest that footpad lesions are painful.

Behavioural assessment of pain in commercial turkeys (Meleagris gallopavo) with foot pad dermatitis.

Two experiments were conducted to investigate the differences in susceptibility to foot pad dermatitis (FPD) of two medium-heavy lines of turkeys, and whether FPD is painful, by detailed analysis of behaviour in birds with and without analgesic treatment (betamethasone). Turkeys housed on dry litter in the first experiment generally had more frequent bouts of different behaviours that were of shorter duration than birds on wet litter. T-patterns (behavioural sequences) were more frequent, varied and complex on dry than on wet litter. Betamethasone-injected birds of line B, but not breed A, had shorter resting and longer standing durations on wet litter than saline-injected birds. In the second experiment, turkeys on wet litter given saline stood less and rested more than all other treatment groups, suggesting that they experienced pain that was alleviated in birds receiving betamethasone. Turkeys on dry litter had more frequent, varied and complex patterns of behaviour than turkeys on wet litter and birds kept on intermediate litter wetness. Betamethasone provision increased pattern variety regardless of litter treatment. Turkeys with low FPD scores transferred to wet litter and given saline injections had a longer total duration of resting and shorter duration of standing compared to betamethasone-treated birds. Low FPD birds transferred to wet litter had a similar number of patterns and total pattern occurrence as high FPD birds transferred to dry litter. Betamethasone increased pattern variety and frequency compared to saline injections whereas overall pattern complexity was similar. It was concluded that wet litter affects the behaviour of turkey poults independently of FPD and that betamethasone may also change the behaviour of turkeys. There was some evidence from analgesic treatment and T-pattern analyses that FPD was painful. However, there was no evidence of differences in susceptibility to FPD of the two commercial hybrids.