Survey on dead on arrival of broiler chickens under commercial transport conditions
Transportation is a main component of the poultry production, and can lead to various levels of stress to chickens, even optimal conditions. It brings about some damages from slight disorder to death. Dead birds between loading at the farm and the slaughtering are described as ‘dead on arrival’ (DOA). DOA is an important indicator of animal welfare and economic loss. DOA could be affected by various factors such as ambient temperature, stocking density in crates, transport distance, lairage time on holding barn, and slaughter age. The aim of this survey to determine the effects of some factors on dead on arrival of broiler chickens under commercial transport conditions.
The survey was carried out in a commercial slaughterhouse on 4062 transfers and 12 723 444 broilers data in commercial conditions during 2018. The data related with animal, transport, ambient at the slaughterhouse and DOA of broiler chicken was recorded by staff throughout the study. Slaughter ages were divided into four groups (up to 39 days, 40 to 42 days, 43 to 44 days, 45 days or more); lairage times were 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 were divided into four groups (up to 15 km, 16 to 50 km, 51 to 100 km, 100 to 200 km) and ambient night temperature were divided into six groups (–5°C to 0°C, 0.1°C to 5°C, 5.1°C to 10°C, 10.1°C to 15°C, 15.1°C to 20°C and 20.1°C to 28°C).
DOA rate was 0.389% in present study. The effect of slaughter age, transport distance, lairage time and temperature category on DOA rate was significant (P<0.001). DOA rate at ≤ 39 days slaughter age was higher than that other slaughter age groups. DOA rate in transport distance up to 15 km (0.448%) was higher than that other transport distance intervals. As transport distance increased DOA rate generally increased. There was positive relationship between DOA rate and lairage time. As lairage time increased DOA rate increased. DOA rate was highest (0.622%) in cold ambient temperatures (–5 0C - 0 0C) while DOA rate was the lowest at temperature range from 5.1 0C to 10 0C (0.334%).
In conclusion, the results of the DOA rates in the present study clearly showed that very short, long distance transport and long lairage time were detrimental for broiler chicken. It is important to avoid from long transport distance and long lairage time in adverse environmental conditions such as too cold or hot temperature. In addition, as broiler chickens of up to 40 days of age was more susceptible to preslaughter stress than other ages; much attention should be paid to this age range in pre slaughter stages.