Evaluation of physical euthanasia for neonatal piglets on-farm.

Twenty-seven neonate piglets (range from 0.35 to 1.17 kg) were evaluated for the effectiveness of blunt force trauma as a method of on-farm cull. Brainstem function, brain injury, and hemorrhage scores (increasing from 0 to 3) were assessed after striking the head against a concrete floor. Electroencephalograms (EEG) from a subset of 15 piglets were recorded before and after blunt force trauma for electrophysiological assessments. Blunt force trauma was performed by a single experienced farmer in a commercial farm by holding the piglet by its both hind legs and striking the head against the concrete floor. All piglets remained recumbent and did not show brainstem reflexes. Only one piglet did not presented tonic/clonic physical activity. The mean time to the onset of persistent isoelectric EEG was 64.3 ± 7.3 s (range 18 to 115). Total power, theta, alpha, and beta power decreased to approximately 45%, 30%, 20%, and 15% from pretreatment power, respectively, by 15-s post-impact. There were no periods of normal-like EEG after the culling. Bruises in the neck and shoulder were found in 67% and 70% of piglets, respectively. All piglets presented skull fractures with 20% having the nasal bone(s) fractured. Brain damage was found in all piglets, mainly in the frontal lobe(s). The occipital lobe(s) presented the greatest frequency of severe damage. The analysis of the radiographs also found a high frequency of fractures in this region. Hemorrhage was most frequent in the frontal, parietal, occipital lobes, and midbrain. When performed correctly with the appropriate weight class, blunt force trauma can be used as an effective method for the on-farm killing of nursing piglets resulting in death. However, this method should not be promoted over more reliable and repeatable cull methods such as captive bolt gun. As with blunt force trauma, there is a significant potential for animal welfare harm associated with inappropriate practice, lack of accuracy, issues with repeatability, and operator fatigue.

Ease of Handling and Physiological Parameters of Stress, Carcasses, and Pork Quality of Pigs Handled in Different Group Sizes.

The effect of different group sizes of pigs (3, 5, and 10 pigs) during handling on physiological parameters, carcasses, and pork quality traits at the farm and slaughterhouse were evaluated in 360 pigs from five farms (four repetitions or group/treatment/farms). Data was analyzed as a factorial of 3 × 5 (3 treatments × 5 farms) to check effects of treatments by analysis of variance in ANOVA. Ease of handling decreased as the group size increased. However, time taken in handling was not influenced by the group size (p > 0.10). Moving pigs in groups of five animals reduced effects on blood cortisol levels (p < 0.05). Fighting and handling lesions in the carcasses increased for bigger handling groups (p < 0.05). Pigs handled in groups of three and ten animals had a higher pHu and initial temperature in Longissimus thoracis and Semimembranosus (p < 0.05) and lower drip loss in Semimembranosus (p < 0.05). However, meat quality classifications of the carcasses were not affected by treatments. Based on the results, moving groups of five pigs seems to be the best strategy to improve animal welfare, carcasses and pork quality.

Risk factors associated with pig pre-slaughtering losses.

The incidence of non-ambulatory non-injured (NANI), non-ambulatory injured (NAI) and dead pigs on-arrival at three Brazilian slaughterhouses were evaluated in 37,962 pigs to identify risk factors linked to them, besides carcass bruises and limb fractures. Total pre-slaughtering losses were 1.18%, in which NAI (0.39%) and NANI (0.37%) incidences contributed the most. A positive relation between on farm steeper ramp slope >20° and the incidence of NAI, NANI and dead pigs at unloading was found. Farm size, pigs/pen, enthalpy at loading, transportation time, truck loading order, muscle thickness and carcass weight, were identified as risk factors for pre-slaughtering losses. Loading procedures influenced the occurrence of limb fractures and bruises (which are a welfare issue and should be reduced). Therefore, personal training on pre-slaughter handling is essential to reduce the risk factors to improve animal welfare and avoid losses during the pre-slaughter process.

Electroencephalographic assessment of pneumatically powered penetrating and non-penetrating captive-bolt stunning of bulls.

The electroencephalographic (EEG) responses of 31 bulls (zebu crossbred cattle) stunned with either pneumatically powered Jarvis penetrating (PCB) or non-penetrating captive bolt (NPCB) was examined. Animals were organized into two treatment groups: PCB (n = 20); and NPCB (n = 11) stunning, both using airline pressures of 220 psi (1517 kPa). All bulls shot with PCB (n = 20/20) had patterns of EEG activity that were inconsistent with consciousness. Of the cattle shot with NPCB 82% (n = 9/11) showed waveforms suggesting complete unconsciousness. After stunning two NPCB bulls had periods of normal EEG activity and maintenance (Ptot, delta, theta, beta) or increased (alpha) spectral power compared to pre-treatment values, indicating incomplete concussion. The study showed that pneumatic PCB stunning was effective in rendering all bulls unconscious, while NPCB was less effective. This highlights the potential animal welfare risks associated with NPCB compared to PCB stunning of mature bulls in commercial abattoirs.

Evaluation of brain damage resulting from penetrating and non-penetrating stunning in Nelore Cattle using pneumatically powered captive bolt guns.

Brain damage resulting from penetrating and non-penetrating stunning of Nelore cattle using pneumatically powered captive bolt guns was evaluated. Heads were shot using penetrating captive bolt gun with 160 psi (P1; n = 10), 175 psi (P2; n = 10), 190 psi (P3; n = 12), and non-penetrating operating with 220 psi (NP; n = 10). Skin and bone thickness, bolt penetration angle, bolt penetration depth, haemorrhage over the cerebral hemispheres and laceration were assessed. Only P1 had shots that failed to perforate the skull (n = 2; 20%). Bolt penetration depth and haemorrhage over the right cerebral hemisphere was significantly (P ≤ 0.05) greater for P3. Subarachnoid haemorrhage over the frontal, parietal and occipital lobes was higher for NP. Lacerations were observed only for penetrating gun in the cortical region of frontal and parietal lobes. Subarachnoid haemorrhage surrounding the brainstem and laceration in the midbrain and pons was only found for P3. Thus, penetrating captive bolt gun operating with 190 psi is more effective to achieve unconsciousness.

Effectiveness of pneumatically powered penetrating and non-penetrating captive bolts in stunning cattle.

This study assessed the effectiveness of penetrating (PCB; 190 psi; N = 363) and non-penetrating captive bolt guns (NPCB; 210-220 psi; N = 92) to stun a total of 455 cattle (Zebu and Zebu Cross). Physical bolt parameters (momentum, kinetic energy and energy density) were evaluated. Clinical indicators of brain function were recorded after stunning (GR), after being hoisted (HO) and at the bleeding rail (BL). Physical bolt parameters (bolt velocity, momentum, kinetic energy, energy density and sectional density) were significantly higher (P < 0.001) for PCB. The need for two or more shots was more frequent for NPCB (210-220 psi; 29% vs. 12%, P < 0.001). Cattle were more likely to collapse at first shot with PCB (190 psi; 99%) compared to NPCB (91%; P < 0.002) which can be attributed to the higher values of bolt physical parameters. Incidence of eyeball rotation (5% vs. 1%) and righting behaviour (7% vs. 1%) were higher (P < 0.001) for NPCB (210-220 psi) at GR than PCB. The NPCB with 210-220 psi had a higher frequency of response to nostril stimulation (2% vs. 0%; P < 0.001) than PCB. Rhythmic respiration was more frequently found for NPCB with 210-220 psi at GR, HO and BL. Therefore, PCB with 190 psi was more effective in ensuring unconsciousness in cattle.

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

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 (160-175psi, N=82) and high (190psi, 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 190psi are inappropriate when shooting adult Zebu beef cattle with pneumatically powered penetrating captive bolt guns.