A total of 800 male cattle (Nelore), aged 28-36 months, stunned by pneumatic captive bolt pistol (operating pressure 160-175psi 11-12bar , air consumption (per cycle) 1.45ft³ 41L , penetrating shaft diameter 0.625 in 15.9mm) in different restrainer systems (mechanical and automated). The traditional mechanical restraint (2.53x0.88x2.20m) did not allow the containment of the animal's head, the automated restrainer (2.60x0.85x2.30m) allowed adjustable sidewall and restraint and elevating the head. The automatic restrainer provided smaller number of shots required for stunning (1.0625±0.013) compared to mechanical (1.2025±0.026) (P≤0.0001), reduced the distance from the ideal point in the first shot (1.246±0.918) and (2.357±1.246) and second (3.042±0.141) and (4.016±0.101) (P 0.0001), and provided no respiratory reflex compared to the mechanical system (0.0275±0.008), (P≤0.001). The automatic restrainer had a higher welfare, improving the efficiency of restraint and stunning of cattle.
stress; stunning system; slaughter; welfare
