Animal and Plant Health Inspection Service, United States Department of Agriculture, Streetsboro, OH 44241, USA.
College of Veterinary Medicine, North Carolina State University, Raleigh, NC 27606, USA.
J Anim Sci. 2021 Mar 1;99(3). doi: 10.1093/jas/skab052.
Euthanasia of mature swine is challenging. Temporal and behind-the-ear locations are two sites that have been identified as alternatives to the more commonly used frontal placement. In stage one, the effectiveness of two penetrating captive bolt gun styles (cylinder or pistol) was evaluated using frontal, temporal, and behind-the-ear placement in anesthetized mature swine (n = 36; weight: 267 ± 41 kg). For stage one, when evaluating treatment efficacy by sex, the cylinder-style equipment was 100% effective in achieving death when applied to all cranial locations (frontal, temporal, and behind-the-ear) for sows; however, the pistol-style equipment was only 100% effective when applied at the behind-the-ear location for sows. For boars, the cylinder-style equipment was 100% effective when applied to the frontal and behind-the-ear location, but the pistol-style equipment was not effective for any cranial location in boars. Therefore, the pistol-frontal, pistol-temporal, pistol-behind-the-ear, and cylinder-temporal were not included for boars, and pistol-frontal and pistol-temporal were not included for sows in stage two. In stage two, commercial, mixed-breed, mature swine (n = 42; weight: 292 +/- 56 kg) were randomly assigned to one of four treatments based on the inclusion criteria described in stage one. A three-point traumatic brain injury (TBI) score (0 = normal; 1 = some abnormalities; 2 = grossly abnormal, unrecognizable) was used to evaluate six neuroanatomical structures (cerebral cortex, cerebellum, hypothalamus, thalamus, pons, and brain stem), and the presence of hemorrhage was also noted. All treatments were 100% effective in stage two. A significant interaction between gun style and placement was determined on predicting total TBI as the cylinder style produced a higher total TBI score compared with the pistol type of the magnitude of +2.8 (P < 0.01). The cylinder style tended to produce a greater TBI score than the pistol in the temporal location (+1.2; P = 0.08). No difference was noted for TBI score behind-the-ear between the cylinder- and pistol-style gun (P > 0.05). TBI tended to be less in boars compared with sows (-0.6; P = 0.08). Hemorrhage was observed in frontal, parietal, occipital, and temporal lobes. This study demonstrated that the cylinder-style captive bolt gun more effectively resulted in brain trauma and death compared with a pistol-style gun and the behind-the-ear and temporal placement showed promise as an alternative placement site for euthanizing mature pigs on-farm.
安乐死成熟的猪是具有挑战性的。颞部和耳后的位置已被确定为比更常用的额部位置更合适的替代位置。在第一阶段，使用麻醉成熟猪（n = 36；体重：267 ± 41 kg）评估了两种穿透式固定螺栓枪样式（圆柱形或手枪式）在额部、颞部和耳后的效果。对于第一阶段，根据性别的治疗效果评估，当将圆柱形设备应用于所有颅部位置（额部、颞部和耳后）时，母猪的效果为 100%有效；然而，当将手枪式设备应用于耳后位置时，母猪的效果仅为 100%有效。对于公猪，圆柱形设备在额部和耳后位置的效果为 100%，但手枪式设备对公猪的任何颅部位置均无效。因此，手枪式额部、手枪式颞部、手枪式耳后和圆柱形颞部不包括在公猪的第二阶段，手枪式额部和手枪式颞部不包括在母猪的第二阶段。在第二阶段，根据第一阶段描述的纳入标准，将商业的、混合品种的成熟猪（n = 42；体重：292 +/- 56 kg）随机分配到四种处理方法之一。使用三点创伤性脑损伤（TBI）评分（0 =正常；1 =一些异常；2 =严重异常，无法识别）评估六个神经解剖结构（大脑皮层、小脑、下丘脑、丘脑、脑桥和脑干），并注意到出血情况。所有处理方法在第二阶段均有效 100%。确定了枪支样式和位置之间的显著相互作用，以预测总 TBI，因为与手枪式相比，圆柱形样式产生的总 TBI 评分高+2.8（P < 0.01）。与手枪式相比，圆柱形式在颞部位置更容易产生更高的 TBI 评分（+1.2；P = 0.08）。圆柱形式和手枪式枪之间在耳后位置的 TBI 评分没有差异（P > 0.05）。与母猪相比，公猪的 TBI 评分较低（-0.6；P = 0.08）。在额部、顶叶、枕叶和颞叶观察到出血。本研究表明，与手枪式枪相比，圆柱形式固定螺栓枪更有效地导致脑损伤和死亡，并且耳后和颞部位置作为农场安乐死成熟猪的替代位置具有一定的潜力。
