Pig production systems and related effects on pre-slaughter animal welfare and meat quality

Pre-slaughter handling practices, such as fasting, transport, mixing and human interventions affect the welfare of pigs and carcase and meat quality individually and cumulatively. Behavioural and physiological studies conducted during the pre-slaughter period revealed that producer-controlled factors at the farm, such as housing system, previous handling experience, genetics, gender, nutrition and slaughter weight can have an impact on pigs' ease of handling and sensitivity to stress, which result in loss of profits for the pork chain due to transport losses, reduced carcase value due to lesions and bruises and meat quality defects. Research has shown that pigs originating from enriched housing conditions, not over-selected for lean deposition and trained to be handled are easier to handle and more resilient to the effects of physical stress prior to slaughter. However, the effects on meat quality are not clear. The production of entire males and immunocastrates can be a valid alternative to surgical castration, provided specific practices are applied to limit aggressiveness in mixed group situations and the risk of bruised carcases. Recommendations for the transport and handling of heavier slaughter pigs must be adapted to improve ease of handling and reduce transport losses, aggressiveness and fatigue-related meat quality defects. The response of pigs to pre-slaughter physical stress and feed deprivation can be affected by ractopamine dietary supplementation, feed composition and feeding regime. The objective of this paper is to overview the effects of on-farm producer-controlled factors on pigs' response to pre-slaughter handling and meat quality, and environmental, social and economic sustainability.