Preslaughter risk factors associated with mortality and bruising in rabbits

Abstract

The aim of this study was to identify and quantify risk factors associated with the mortality and bruising rate prevalence in 975 commercial batches of growing rabbits delivered for slaughter. The effects of environmental temperature, batch size (number of rabbits delivered per batch), journey and lairage duration on dead on arrival (DOA) and bruising prevalence were investigated and expressed as an odds ratio (OR). This value is equivalent to the relative risk, assessing each specific factor relative to its reference category (OR=1). The overall mortality rate of 0.09% was affected by environmental temperature, batch size, journey and lairage duration. A significantly increased DOA risk was associated with very low (<7.3°C; OR=1.28) and very high (≥22.6°C; OR=1.85) environmental temperatures. In addition, a significantly higher odds ratio (OR=1.70) was observed in the largest batches (≥3681 rabbits). Both increasing journey and lairage duration dramatically increased the risk of death during the preslaughter period. Rabbits belonging to batches either transported or laired for a long time had a roughly threefold higher risk of death. The overall prevalence of bruise percentage was 2.13% and was affected by environmental temperature, batch size and journey duration. Environmental temperatures ranging from 7.3 to 12.4°C decreased the risk of bruising (OR=0.90), whereas temperatures from 17.5 to 22.6°C and higher than 22.6°C exhibited significantly higher OR values (1.22 and 1.34, respectively). Moreover OR values were higher for small (734 to 1716 rabbits; OR=1.21) and very small (<734 rabbits; OR=1.36) batches, but also for very large ones (≥3681; OR=1.10). As for journey time, transport duration from 308 to 411 min and longer than 411 min duration increased bruising risk (OR= 1.15 and 1.19, respectively), while this risk was slightly decreased (OR=0.96) for medium journey duration (205 to 308 min). In conclusion, even though average DOA and bruising rates were quite low compared with chickens and turkeys, further logistics and planning improvements should be made in batch harvesting to reduce transport and lairage duration as far as possible in conjunction with extremely low and high environmental temperatures.