Transport av slaktkyckling från gård till slakteri - studier av klimat och analys av dödlighet - förslag till förbättringar

摘要

Investigations were performed to identify the thermal environment in three different types of broiler transport vehicles from the site of production to processing plants in Sweden and Denmark. Vehicles with mechanical ventilation systems (F-vehicles) had pressure fans in combination with adjustable openings in front, sides and back. F-vehicles were winter configured by turning the fans off and increasing the natural ventilation (FN-vehicles). The naturally ventilated vehicles (N-vehicles) had adjustable openings in front, back and sides of the vehicle. Tarpaulin vehicles (K-vehicles) were Danish vehicles constructed with solid roof and front, and detachable tarpaulin sides for summer and winter configurations. All broilers were mechanically harvested. Long term investigations were performed on transport documentations from 2,310 Swedish vehicles during Oct. 2005 to Oct. 2006 (F- and FN-vehicles) and Apr. 2006 - Oct. 2006 (N-vehicles). The number of broilers dead on arrival (DOA) was 0.14% and 0.39% for F- and N-vehicles, respectively. Transport time up to 3.5 h, ambient- and lorry temperature had no effects on DOA (R2=0,013), however a small increase was seen at ambient temperatures above 17ºC (NS). Intensive studies of twenty three transports were performed during Jun. – Aug. 2006 and Dec. 2006 – Feb. 2007, where levels of temperature, humidity and carbon dioxide (CO2) in containers at different locations of the vehicles were measured during loading and transit. Loading practise had an impact on temperature development in the F-vehicle and to reduce heat stress they should be loaded back to front. Keeping both sides of the vehicle open during loading was important to avoid increasing temperatures in the containers. In F-vehicles with fans turned off the internal climate becomes unstable, especially in the trailer. In N-vehicles during summer temperatures were high, exceeding 25°C in the lower, central parts of the trailer. In these certain parts of the vehicle air flow needs to be increased. During transport large internal climatic differences were found between containers in both F- and N-vehicle. A calculated temperature-humidity index (THI) was at acute dangerous levels in certain containers. In N-vehicles the drawers’ construction was limiting ventilation. K-vehicles had the most acceptable climate during summer, but unstable during winter with risk for temperatures down to 0°C. In conclusion, the ventilation system designs in the vehicles are crucial for appropriate climate control and are in several cases in need of revising or reconstruction.