The Effects of Simulated Transportation Conditions on the Welfare of White-Feathered Layer Pullets

Abstract

This study evaluated the effects of various temperature (T) and relative humidity (RH) combinations, and durations (D), on the welfare of pullets during simulated transportation. In a 5x2 factorial arrangement (T/RH combinations, and D (three replications)) pullets (n=240) were randomly assigned to one of five treatments, 21°C 30%RH (21/30), 21°C 80%RH (21/80), 30°C 30%RH (30/30), 30°C 80%RH (30/80), and -15°C (-15), for a four or eight hour D. Pre-treatment, pullets were orally administered data loggers (recorded core body temperature (CBT)), which were retrieved post-treatment. Foot T, body weights, and blood samples were taken pre- and post-treatment. Video recorded during exposure and analyzed for behaviour. Post-treatment, pullets were slaughtered, and carcasses were analyzed for muscle tissue characteristics (pH, water-holding capacity, and colour). In a randomized complete block design, data were analyzed via Proc Mixed (SAS 9.4). Differences were determined at P≤0.05. Pullet CBT during the last hour of exposure was lowest in the -15 treatment. Pullet ∆CBT was greater in the eight hour D compared to the four hour D. Compared to the -15 treatment, pullets in 30/30 and 30/80 surveyed more, and pullets in 30/80 were more active. Pullets exposed to 30/30 and 30/80 panted more. Along with the 21/30 treatment, pullets in the -15 and 21/30 treatment spent more time motionless, compared to the 30/30 and 30/80 treatments. Pullets exposed to -15 preened less compared to 21/80 and 30/30. Foot T were lowest in the pullets exposed to -15, and higher in the pullets in 30/80 compared to the neutral and cold treatments. Final blood glucose levels were higher in pullets in 30/80 compared to 21/30 and 21/80. The partial pressure of CO2, total CO2, and bicarbonate levels were lower in pullets exposed for eight hours. Live shrink (kg) was higher in pullets exposed to 30/30 and 30/80 (compared to 21/80), and in the eight hour D (kg and %). No biologically significant impacts were found for pullet muscle tissue characteristics. Exposure to thermal stress required pullets to implement behavioural and physiological mechanisms to maintain homeostasis. A D of up to eight hours had minimal impacts on pullet well-being.