Epsilon Archive for Student Projects

Abstract

There are a majority of approved stunning methods for pig slaughter in Sweden. These include captive bolt stunner, rifles (including shotguns), electricity and carbon dioxide. Carbon dioxide and electricity are among the most common methods.

Carbon dioxide creates unconsciousness through a hypercapnic hypoxic condition and by acidosis that leads to a pH decrease in the central nervous system. The method has several advantages but also serious disadvantages. When carbon dioxide has been used for stunning, reactions like sneezing, gasping for air and vocalizations have been seen, which may be interpreted as signs of fear, pain and stress in pigs.

Stunning by electricity is obtained through electrodes placed on each side of the head that creates a next to epileptic seizure in the animal which leads to unconsciousness. Again, there are disadvantages because the pigs are stunned one at a time instead of in flock and there is a risk that the electrodes are positioned incorrectly and that an insufficient stunning occurs prior to bleeding.

A new stunning method with fewer disadvantages for the animals would be desirable. This study is therefore part of a major project aimed for evaluating nitrogen bound in foam as an alternative stunning method for slaughtering and killing pigs. In this study, pigs’ behaviours has been recorded and evaluated for 3 different treatments. A total of 30 piglets has been included in the study, and randomly divided into 3 different groups of 10 pigs in each group. The pigs' behaviours has been recorded when they are in an empty stunning box, when they are in the stunning box and the noise from the foam producing machine is heard while water is leaking into the box, and also when they hear the noise from the foam producing machine and the stunning box is filled with air-filled foam.

The result of the study shows a statistically significant difference between the different treatments regarding to the rate of exploratory behavior/sniffing of the floor (touching of the snouts on the floor). Pigs in the foam treatment explored the floor less frequently than pigs in the other two treatments, which may indicate a discomfort to stay with the snout in the foam or difficulty breathing in the foam. The pigs in the foam treatment slipped more than the pigs in the treatment of an empty and quiet box, which is likely due to the foam, making the floor slippery. For other registered behaviours, no statistically significant difference was found between treatments.