Survey on dead on arrival of broiler chickens under commercial transport conditions

Abstract

Transportation is a major component of the global commercial poultry production system and it can lead to various levels of stress in chickens, even under optimal conditions. It can cause harm ranging from slight disorders to death. Birds that die between loading at the farm and slaughtering are described as 'dead on arrival' (DOA). DOA is an important indicator of animal welfare and financial losses. It can be influenced by various factors such as ambient temperature, stocking density in crates, transport distance, lairage time in the holding barn and slaughter age. The aim of this survey was to determine the effects of some factors on the incidence of the phenomenon 'dead on arrival' in broiler chickens under commercial transport conditions. This survey was carried out in a commercial slaughterhouse on the basis of data for 4,062 transfers and 12,723,444 broilers under commercial conditions during 2018. The data related to slaughter age, transport distance, lairage duration, ambient temperature at the slaughterhouse and the incidence of DOA of broiler chickens was recorded by staff throughout the study. Slaughter age was divided into four groups (up to 39 days, 40 to 42 days, 43 to 44 days, 45 days or more); lairage duration was divided into five groups (up to 60 min, 61 to 120 min, 121 to 180 min, 181 to 240 min, 241 min or more); transport distance was divided into four groups (up to 15 km, 16 to 50 km, 51 to 101 km, 100 to 200 km) and ambient temperature at the slaughterhouse was divided into six groups (-5 degrees C to 0 degrees C, 0.1 degrees C to 5 degrees C, 5.1 degrees C to 10 degrees C, 10.1 degrees C to 15 degrees C, 15.1 degrees C to 20 degrees C and 20.1 degrees C to 28 degrees C). Across the present study, the overall DOA rate was 0.389%. The effects of slaughter age, transport distance, lairage duration and temperature on the DOA rate were all significant (P<0.001). The DOA rate at <= 39 days slaughter age was higher than that of the other groups (P<0.001). Furthermore, the DOA rate for transport distance up to 15 km (0.448%) was higher than that for the other distance intervals (P<0.001). As the transport distance increased, the DOA rate usually increased (P<0.001). In addition, there was a positive relationship between DOA rate and lairage duration (P<0.001). As the lairage duration increased, the DOA rate increased. In addition, the DOA rate was highest (0.622%) at cold ambient temperatures (-5 degrees C - 0 degrees C) and lowest at 5.1 degrees C to 10 degrees C (0.334%). In conclusion, the results of the current study regarding DOA rates clearly showed that short or long distance transport and long lairage duration were extremely detrimental to the health of broiler chickens. It is therefore important to avoid long or short distance transportation and long lairage duration, especially in adverse environmental conditions such as sub-zero and high temperatures. In addition, broiler chickens of up to 40 days of age were more susceptible to pre-slaughter stress than other ages. Therefore, more attention should be paid to the management of broilers in this age range in the pre slaughter period.