TRANSPORT OF SLAUGHTER PIGS BY TRUCK OVER A LONG-DISTANCE - SOME ASPECTS OF LOADING DENSITY AND VENTILATION

During transport of pigs over a long distance many factors affect the condition of the animals and the meat quality. The effects of loading density, ventilation and showering on animal welfare and meat quality were studied. Eleven 25-h experimental journeys were performed each with 60 pigs (average liveweight 110 kg). The experimental pigs were allocated to (1) groups with the legal ventilation system or with variable ventilation holes (to close at < 16-degrees-C and to open at > 20-degrees-C), while they were showered during six journeys and to (2) three loading densities: 186, 232 and 278 kg/m2. The live weight loss averaged 3.9 (s.d. 0.8) kg/pig. In compartments with a density of 278 kg/m2 not all animals were able to lie down at the same time which resulted in a continual changing of positions. The pH values of the m. semimembranosus (SM) and m. longissimus (LD) and the rigor mortis were significantly (P < 0.05) increased after 45 min post mortem with a higher loading density. Significant differences were not observed in meat quality parameters between pigs transported under the different ventilation systems. However, a significant interaction between showering and compartments in the truck was found for pH of the SM. A significant interaction between loading density, compartments in the truck, ventilation and showering was found for rigor mortis. An interaction between showering during transport and loading density was found for carcass weight. It is suggested that the loading density should be limited at about 232 kg/m2 (approximately 0.47 m2/pig) for animal welfare and meat quality reasons and that strong interactions between transport factors may veil main effects.