What can pig carcases tell us about farm welfare?
Welfare assessments during production come with time, economic and biosecurity costs, so what are the options for assessing welfare at different stages of the food production chain? Could carcase analysis provide a viable alternative?
by Dr Lauren Edwards, The Pig Site
6 September 2019
Across society, concern for animal welfare is increasing, and consumers often want assurances that their pork has come from animals that were reared responsibly. The well-being of pigs on farms is monitored using animal-welfare audits and farm assurance schemes. However, these on-farm assessments take time to conduct, are costly and can present potential biosecurity risks, as auditors travel between farms to carry out their checks. Monitoring pig welfare at abattoirs instead of farms may provide an alternative when conducting large-scale assessments.
Monitoring animal welfare at the abattoir might at first sound counter-intuitive, however, there are many advantages to conducting welfare assessments here, compared to carrying them out on farms (see Table 1). These advantages largely relate to the reduced costs and travel times for inspectors, but also include improved biosecurity conditions and better visibility of the animals during inspections. By utilising data that are already collected by pig abattoirs during carcass inspection, the health and welfare status of large numbers of pigs can be more easily monitored.
During the slaughter process, each carcass is subjected to a routine meat inspection in which the carcass is examined for signs of illness or injury. These meat inspections were originally developed to detect any disease risks for humans, but are now also used to identify and remove any damaged parts of the carcass that may be unappealing to consumers, such as bruises and scratches. Thus, meat inspections generate large amounts of data on the health and injury status of all pigs sent for slaughter. These data represent an important resource that is currently being used for disease monitoring and epidemiological studies, and could represent an enormous opportunity for monitoring pig welfare.
During carcass inspection, any injuries present can be categorised as having occurred recently (acute), or having occurred some time ago (chronic). By classifying injuries as acute or chronic, we can start to estimate when they happened. Acute injuries that occurred just prior to slaughter are likely to have taken place during transport or lairage, whereas older injuries are indicative of the conditions on farm. A list of the different welfare indicators that could potentially be assessed at slaughter are presented in Table 2. There has been a lot of recent research aimed at validating these measures as reliable indicators of on-farm welfare.
As we can see from Table 2, there are many conditions that can be detected at the abattoir. However, researchers are still determining which conditions are reliable indictors of pig welfare during transport and on farm. Skin and tail lesions show promise...
more, including tables, references