Efficiency of low versus high airline pressure in stunning cattle with a pneumatically powered penetrating captive bolt gun

Abstract

The efficiency of stunning cattle was assessed in 443 animals (304 pure Zebu and 139 crossbred cattle), being mainly mature bulls and cows. Cattle were stunned using a Jarvis pneumatically powered penetrating captive bolt gun operating with low (160-175 psi, N= 82) and high (190 psi, N= 363) airline pressure, which was within the manufactures specifications. Signs of brain function and the position of the shots on the heads were recorded after stunning. Velocity of the captive bolt and its physical parameters were calculated. Cattle shot with low pressures showed more rhythmic respiration (27 vs. 8%, P < 0.001), less tongue protrusion (4 vs. 12%, P = 0.03) and less masseter relaxation (22 vs. 48%, P < 0.001). There was an increased frequency of shots in the ideal position when cattle were shot with the low compared to high airline pressures (15.3 vs. 3.1%). Bolt velocity and its physical parameters were significantly (P < 0.01) higher when using high pressure. Airline pressures below 190 psi are inappropriate when shooting adult Zebu beef cattle with pneumatically powered penetrating captive bolt guns.

Cattle stunning with a penetrative captive bolt device: A review

“…The results of Oliveira et al. (, ), who did not determine a significant relationship between the shot position or the distance from the ideal location and clinical symptoms of consciousness/unconsciousness in slaughtered animals, agree with this contention. Tests were performed on 455 animals.…”

“…Pneumatic stunning devices are equipped with bolts of larger diameter and length and, therefore, greater weight (Table ). They are used extremely widely at large‐capacity abattoirs (Oliveira, Gregory, Costa, Gibson, & da Costa, ).…”

“…Oliveira et al. () tested pneumatically controlled stunning devices with low operating pressure (1.10 MPa/160 psi; 1.21 MPa/175 psi) and high operating pressure (1.31 MPa/190 psi) at two abattoirs in Brazil. The weight of the bolt was constant (0.297 kg).…”

“…As stated by Oliveira et al. (), the limit values given above are based on classic stunning devices using a cartridge.…”

“…Pneumatic stunning devices are equipped with bolts of larger diameter and length and, therefore, greater weight (Table 1). They are used extremely widely at largecapacity abattoirs (Oliveira, Gregory, Costa, Gibson, & da Costa, 2017). Dörfler et al (2013) tested three types of cartridge-fired stunning devices from a single manufacturer, with a captive bolt length of 80, 85, and 125 mm, at an abattoir in Germany.…”