Effect of the position of the gun on the brain damage caused by the captive bolt when stunning cattle
The impact of the position of the stun gun brain damage was studied in 19 cattle. The aim was to define a reliable method of damaging the Ascending Reticular Activating System (ARAS), which is strongly involved in consciousness. The positions tested were two positions located at the intersection of the diagonals between the animal's eye and the base of the opposite horn (Low position: Eye-hornB; High position: Eye-hornH) and two positions located in the middle of the line going from the top of the head to the line connecting the animal's two eyes (Low position: MedianB; High position: MedianH). When using the Eye-HornB position, the bolt usually passed below the brain. The Eye-HornB and Eye-HornH positions were influenced by the shape of the head. The MedianB and Eye-HornH positions resulted in damage to the ARAS in approximately half and three-quarters of the animals, respectively. The MedianH position produced satisfactory damage to the ARAS (within the target zone: 95% of the animals; at the limit of the target zone: 5% of the animals). The disadvantages of the latter position are a potentially too caudal position in some animals and the greater difficulty to use outer canthi of the eyes as a landmark. In conclusion, placing the gun 1 cm lower than the MedianH position, or about 2 to 3 cm higher than the Eye-hornH or MedianB positions, maximises the probability of damaging the ARAS, while limiting the risk of a too caudal position.
