The effects of fear of humans and pre-slaughter handling on the meat quality of pigs

Abstract

This study using 90 commercial pigs examined the relationships between the handling that pigs received immediately prior to slaughter and some measures of their meat quality. A number of significant correlations were found between the number of negative interactions that pigs received from the stockperson and subsequent meat quality of the pigs. For example, the number of highly negative interactions received by the pigs was negatively (P < 0.01) correlated with plasma glucose concentrations post-slaughter and positively correlated (P < 0.05) with both post-slaughter plasma lactate concentrations and the light reflectance of the ham. Most of these highly negative interactions were prods with an electric goad. Both the number of interactions by the pig with the experimenter in a standard test used to assess fear of humans and the time taken by the pig to move along the final route to the stunning area were positively correlated (P < 0.05) with the number of highly negative interactions received by the pig prior to slaughter. Regression analysis revealed that the number of highly negative interactions received by the pig, plasma lactate concentration, and the time to physically interact by the pig with the experimenter in the standard test were significant (P < 0.001) predictors of ham lightness. These variables accounted for 18% of the variance in ham lightness. It is concluded that there are some important associations between the behaviour of the stockperson and the muscle physiology of pigs. Although no significant associations were found between stockperson behaviour and ham pH, the correlations between stockperson behaviour, plasma lactate and glucose, and muscle lightness reflect increased muscle glycogenolysis, presumably associated with increased handling stress prior to slaughter. Such results indicate the opportunity to manipulate the behaviour of stockpeople prior to slaughter to improve meat quality.