The effect of stocking density in transit on the carcass quality and welfare of slaughter pigs: 2. Results from the analysis of blood and meat samples

In a trial Involving 2496 pigs, the influences on blood profile and pork qu ality of stocking densities ranging from 201 to 321 kg m(-2) were examined. The pigs came from four different farms and were killed in 16 weekly batch es. They were transported for on average 3 hr and held in lairage for 1 hr. Higher stocking densities resulted in more physical stress to the pigs bas ed an the activity of the enzyme CPK in the blood. Stocking density did not apparently affect psychological stress and high densities did not result i n dehydration. The colour, water holding capacity and instrumentally-determ ined texture of the pork from the carcasses of the pigs were not affected b y stocking density. The experimental design and precision of the measuremen ts were sufficient to defect numerous differences in blood profile and pork quality between pigs from the four source farms. These differences probabl y related to different degrees of stress-susceptibility. The results sugges t that the highest stocking density examined (321 kg m(-2)) is unacceptable for the transport of pigs. The second highest density (281 kg m(-2)) produ ced relatively little evidence of an adverse effect on the welfare of pigs. It may be scientifically acceptable for short journeys (less than or equal to 3 hr) but not for longer ones where pigs need more space to lie dawn. ( C) 1998 Elsevier Science Ltd. All rights reserved.