Validation of a portable pneumatic captive bolt device as a one-step method of euthanasia for use in depopulation of feedlot cattle.

OBJECTIVE: To validate the effectiveness of a penetrating captive bolt device with a built-in low-pressure air channel pithing mechanism (PCBD) as a 1-step method for euthanasia of cattle. DESIGN: Clinical trial. ANIMALS: 66 feedlot steers and heifers (weight, 227 to 500 kg [500 to 1,100 lb]) that were not expected to survive or finish the feeding period with their cohorts. PROCEDURES: Cattle were transported to a university facility and euthanized with the PCBD. For each calf, clinical variables were monitored and recorded immediately before and for at least 10 minutes after application of the PCBD. Following euthanasia, the head of each calf was removed and trauma to the brain and skull was assessed and scored. RESULTS: Death was successfully achieved with the PCBD without application of an ancillary technique in all 66 cattle; however, 4 (6%) cattle required a second or third shot from the PCBD because of technical errors in its placement. All shots from the PCBD that entered the cranial vault successfully rendered cattle unconscious without a return to sensibility. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicated that the PCBD was an effective 1-step method of euthanasia for use in mass depopulation of feedlot cattle.

Effectiveness of a nonpenetrating captive bolt for euthanasia of 3 kg to 9 kg pigs.

The objective of this study was to determine the effectiveness of a nonpenetrating captive bolt, Zephyr-E, for euthanasia of suckling and weaned pigs from 3 to 9 kg (5-49 d of age) using signs of insensibility and death as well as postmortem assessment of traumatic brain injury (TBI). The Zephyr-E was used by 15 stock people to euthanize 150 compromised pigs from 4 farrowing and nursery units from commercial farms and 2 research stations. Brainstem reflexes, convulsions, and heartbeat were used to assess insensibility, time of brain death, and cardiac arrest following Zephyr-E application. Skull fracture displacement (FD) was quantified from computed tomography (CT) scans (n = 24), macroscopic scoring was used to assess brain hemorrhage and skull fracture severity (n = 150), and microscopic scoring was used to assess subdural hemorrhage (SDH) and parenchymal hemorrhage within specific brain regions that are responsible for consciousness and vital function (n = 32). The Zephyr-E caused immediate, sustained insensibility until death in 98.6% of pigs. On average, clonic convulsions (CC) ceased in 82.2 s (± 3.4 SE), brain death was achieved in 144.9 s (± 5.4 SE), and cardiac arrest occurred in 226.5 s (± 8.7 SE). Time of brain death and cardiac arrest differed significantly among stock people (P = 0.0225 and P = 0.0369). Age was positively related to the duration of CC (P = 0.0092), time of brain death (P = 0.0025), and cardiac arrest (P = 0.0068) with shorter durations seen in younger pigs. Average FD was 8.3 mm (± 1.0 SE). Macroscopic scores were significantly different among weight classes for subcutaneous (P = 0.0402) and subdural-ventral (P = 0.0037) hemorrhage with the lowest severity hemorrhage found in the 9-kg weight category. Microscopic scores differed among brain sections (P = 0.0070) for SDH with lower scores found in the brainstem compared to the cerebral cortex and midbrain. Parenchymal hemorrhage differed among brain sections (P = 0.0052) and weight categories (P = 0.0128) with the lowest scores in the midbrain and brainstem and the 7- and 9-kg weight categories. The Zephyr-E was highly effective for the euthanasia of pigs up to 9 kg (49 d) based on immediate insensibility sustained until death. Postmortem results confirmed that severe skull fracture and widespread brain hemorrhage were caused by the Zephyr-E nonpenetrating captive bolt.