Movements after Captive Bolt Stunning in Cattle and Possible Animal- and Process-Related Impact Factors-A Field Study

Movements in cattle after captive bolt stunning cause problems in the slaughter process and lead to uncertainties in assessing stunning effectiveness. The objective of this study was to categorize and quantify these movements and determine animal- and process-related impact factors, as well as connections to stunning effectiveness and shooting position. In total 2911 cows, heifers, and bulls (dairy, beef, and crossbreeds) were examined (mean age 3.02 years). Movements from landing until at least four minutes after sticking were recorded by action cams (Apeman® A100). Nine movement categories were defined ("kicking hind limb", "twitching", "bending and stretching hind limb", "lifting and bending forelimb", "body arching laterally", "body arching ventrally", and "arching backwards"). According to the movement severity, a score was assigned to each category. The scores were summed, either for certain process intervals, e.g., LANDING (ejection from the stunning box), HOISTING, or STICKING, or for the total time between LANDING and end of the FOURTH MINUTE OF BLEEDING (sum score). Statistical analysis (ANOVA) was performed on the scores. Only 6.6% of cattle showed no movement. Most movements occurred during STICKING and FIRST MINUTE OF BLEEDING, occurring rarely up to 8 min after sticking. While cows moved most at LANDING, bulls and heifers moved more if all process intervals were considered. The sum score was highest in German Angus, Charolais, and Limousin and lowest in Brown Swiss and Simmental. The score at LANDING was highest in German Angus and Black Holstein. The use of pneumatic stunners and an increase in bolt-exit length significantly reduced movements. No impact of stunning effectiveness on movements was found, but only 19 cattle showed reduced effectiveness.

False aneurysms in carotid arteries of cattle and water buffalo during shechita and halal slaughter

It has previously been shown that the cattle brain is supplied with blood via a basi-occipital plexus, in addition to branches from the carotid and basilar arteries. In addition it has been shown during conventional stunning and slaughter that the carotid arteries in cattle can develop false aneurysms at their severed ends and this can curtail exsanguination. This investigation examined whether false aneurysms can occur during religious slaughter, and during bleeding following electrical stunning that simultaneously induced a cardiac arrest. The prevalence of large (>3cm outer diameter) false aneurysms in cattle carotid arteries was 10% for both shechita and halal slaughter. The prevalence of animals with bilateral false aneurysms (at least 2cm in one artery and at least 3cm diameter in the opposite artery) was 7% and 8% for shechita and halal slaughter, respectively. No false aneurysms occurred during bleeding in cattle that were electrically stunned and simultaneously developed a cardiac arrest. The combination of false aneurysms and collateral routes to the brain present a risk of sustained consciousness during religious slaughter in cattle.

[CO2 stunning of broilers and turkey hens]

Stunning of poultry is still not solved satisfactorily. This concerns the requirements of animal welfare, meat quality and working conditions in the lairage, stunning and debleeding area. In an investigation of combined CO2-/O2-stunning in a new gas stunning system stress reactions of the animals during the induction phase and stunning effectivity were recorded in 7,000 chicken and 3.825 turkeys. During the induction phase (here: chicken 41 sek./turkeys 25-65 sec.) the animals first staid calm and then showed beak-opening as a consequence of the breathing stimulating effect of CO2. As a further sign of the aversiveness against CO2 the animals showed head shaking and wing flapping. The used settings of gas concentrations and stunning time in the system investigated lead to a very deep stunning resp. Killing of the animals. Therefore the debleeding cut could be performed late (chicken 44-55 sec., turkeys 54-90 sec.) after leaving the system without animals regaining consciousness. The stunning of turkeys with a mixture of CO2 and oxygen is an improvement according to animal welfare requirements because unnecessary pain and suffering, happening very often with electrical stunning, can be avoided. As far as animal welfare in chicken stunning is concerned it must be evaluated if gas stunning means an improvement because stress during the till now relatively long induction phase must be put into relation with comparably lower stress caused by hanging upside down and a fast and safe working electrical stunning unit.