This study evaluated the ability of 2 penetrating captive bolt (PCB) types (PISTOL, INLINE) to reach and disrupt the thalamus when applied in 2 placements (FRONTAL, BEHIND EAR) to chilled cadaver heads (N = 60) from sows >200 kg. Heads were randomly distributed across 6 treatments (n = 10): FRONTAL-INLINE, FRONTAL-PISTOL, FRONTAL-NO SHOT, BEHIND EAR-INLINE, BEHIND EAR-PISTOL, and BEHIND EAR-NO SHOT. The FRONTAL shot was placed 3.5 cm superior to the optic orbits at the midline; the BEHIND EAR shot was placed directly caudal to the pinna of the ear on the same plane as the eyes and targeting the middle of the opposite eye. For INLINE treatments, a Jarvis PAS-Type C 0.25R Super Heavy Duty PCB with a Long Bolt and 6.0 GR power loads was used. For PISTOL treatments, a Jarvis PAS-Type P 0.25R Pistol PCB with a Long Stunning Rod Nosepiece Assembly and 3.5 GR power loads was used. Heads were split along the bolt with a band saw. Tissue depth measurements are reported as Mean ± SE followed by 97.5% one-sided upper reference limit (URL). Total tissue thickness was less (P < 0.0001) at the FRONTAL (56.31 ± 1.76 mm; URL: 73.17 mm) than the BEHIND EAR placement (95.52 ± 3.30 mm; URL: 126.53 mm). Thalamic depth was less (P < 0.0001) at the FRONTAL (78.31 ± 1.32 mm; URL: 88.19 mm) than the BEHIND EAR placement (111.86 ± 3.22 mm; URL: 135.99 mm). The effective angle was greater (P < 0.0001) at the FRONTAL (4.72 ± 0.20°) than the BEHIND EAR placement (3.22 ± 0.17°). Potential for bolt-brain contact was not different (P = 1.0000) between FRONTAL-INLINE (10/10, 100% ± 0.01%), FRONTAL-PISTOL (10/10, 100% ± 0.01%), BEHIND EAR-INLINE (9/10, 90% ± 9.49%), and BEHIND EAR-PISTOL (10/10, 100% ± 0.01%); brain damage (P = 0.5577) between FRONTAL-INLINE (9/9, 100% ± 0.02%), FRONTAL-PISTOL (10/10, 100% ± 0.02%), BEHIND EAR-INLINE (4/10, 40% ± 15.49%), and BEHIND EAR-PISTOL (1/10, 10% ± 9.49%); potential for bolt-thalamus contact (P = 0.0683) for FRONTAL-INLINE (2/10, 20% ± 12.65%), FRONTAL-PISTOL (8/10, 80% ± 12.65%), BEHIND EAR-INLINE (7/9, 77.78% ± 13.86%), and BEHIND EAR-PISTOL (9/9, 100% ± 0.02%); or thalamic damage (P = 0.8041) for FRONTAL-INLINE (1/10, 10% ± 9.49%), FRONTAL-PISTOL (1/10, 10% ± 9.49%), BEHIND EAR-INLINE (2/8, 25% ± 15.31%), and BEHIND EAR-PISTOL (0/9, 0% ± 0.00%). The FRONTAL placement with an INLINE PCB may present the least risk of failure for the PCB euthanasia of mature sows >200 kg body weight due to less total tissue thickness and thalamic depth, greater effective angle, and prevalent brain damage.
Euthanasia is a necessary procedure to safeguard animal welfare on swine farms. Penetrating captive bolt (PCB) is often used to euthanize sows by passing a metal bolt through the animal’s skull and into the brain. This causes severe brain damage with the anticipated result of an immediate loss of consciousness. This study evaluated frontal and behind-ear PCB placements for sows weighing more than 200 kg with 2 commercially available types of PCB devices. The frontal placement, when used with an inline free-flight PCB device, may be more reliable than other placement and device combinations due to less total tissue thickness, more room for error with positioning the PCB, and prevalent brain damage.

Killing of farmed saltwater crocodiles involve stunning with a penetrative captive bolt device, followed by a cut across the nape of the neck and physical destruction of the brain to ensure death. This study was a welfare-based assessment of the use of a penetrative captive bolt device in saltwater crocodiles, to determine whether it satisfies the criteria of a humane stunning method and can be regarded as a direct killing method without the need for the application of an adjunct method. Methods used were electroencephalogram (EEG), observation of post-stun behavior, and postmortem examination of gross pathology of the cranium and brain. 30 of 30 animals, demonstrated immediate and irreversible loss of consciousness. There was extensive damage to the brain in all animals, deemed to be inconsistent with cortical function and possible recovery. The CASH Special 0.22 penetrative captive bolt pistol (1.25 grain cartridge), applied to the top of the cranial plate, produced immediate and irreversible unconsciousness in all the animals studied. This method satisfies animal welfare expectations, providing crocodile processors with a technique that contributes to a humane killing process.

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.

Penetrating captive bolt (PCB) is the primary method of preslaughter stunning for cattle and is also used for on-farm euthanasia. The objective of this study was to quantify the impact of cooling on the soft tissue thickness, cranial thickness, total tissue thickness, and cross-sectional brain area of cadaver heads collected from mature (> 30 mo of age) dairy cows following the application of a PCB stun in a frontal placement. Hide-on cadaver heads were obtained from culled dairy cows (N = 37) stunned in a frontal location using a handheld PCB device (Jarvis Model PAS-Type C 0.25R Caliber Captive Bolt, Long Bolt) at a commercial slaughter establishment. Following transport to the University of Wisconsin-River Falls, heads were split at midline along the bolt path by a bandsaw and then underwent FRESH, CHILL24, CHILL48, and CHILL72 refrigeration treatments. The FRESH treatment involved images collected immediately after splitting each head, the CHILL24 treatment involved images collected after 24 h of refrigeration, the CHIL48 treatment involved images collected after 48 h of refrigeration, and the CHILL72 treatment involved images collected after 72 h of refrigeration. Measurements of soft tissue thickness, cranial thickness, total tissue thickness, and cross-sectional brain area were recorded for each refrigeration treatment. Soft tissue thickness did not differ caudal to (P = 0.3751) or rostral to (P = 0.2555) the bolt path. Cranial thickness did not differ caudal to (P = 0.9281) or rostral to (P = 0.9051) the bolt path. Total tissue thickness did not differ caudal to (P = 0.9225; FRESH: 24.77 mm, CHILL24: 23.93 mm, CHILL48: 24.27 mm, CHILL72: 42.30, SE: 0.86) or rostral to (P = 0.8931; FRESH: 24.09 mm, CHILL24: 23.99, CHILL48: 24.26, CHILL72: 24.43 mm, SE: 0.79 mm) the bolt path. Cross-sectional brain area was not different (P = 0.0971) between refrigeration treatments (FRESH: 9,829.65 ± 163.87 mm2, CHILL24: 10,012.00 ± 163.87 mm2, CHILL48: 9,672.43 ± 163.87 mm2, CHILL72: 10,235.00 ± 166.34 mm2). This study demonstrated that FRESH tissue parameters can be determined from cattle cadaver heads refrigerated for 24, 48, or 72 h.

Penetrating captive bolt (PCB) is a common method of euthanasia for swine but has not been evaluated for mature swine < 200 kg body weight (BW). The objectives were to determine tissue depth, brain contact plane, and visible brain tissue damage (brain damage[BD]) for the common FRONTAL (F) and alternative TEMPORAL (T) and BEHIND EAR (BE) placements for PCB use on sows and boars weighing < 200 kg. Cadaver heads were obtained from 30 sows and 30 boars (estimated BW, mean ± SD; sows: 165.8 ± 22.4 kg; boars: 173.6 ± 21.4 kg) from a slaughter establishment after electrical stunning and exsanguination. Heads were cooled at 2 to 4 °C for approximately 64 h. A Jarvis PAS-Type P 0.25R PCB with a Long Stunning Rod Nosepiece Assembly and a 3.5 GR power load was used for all PCB applications at the following placements: F-3.5 cm superior to the optic orbits at midline, T-at the depression posterior to the lateral canthus of the eye within the plane between the lateral canthus and the base of the ear, or BE-directly caudal to the pinna of the ear on the same plane as the eyes and targeting the middle of the opposite eye. For sows, the bolt path was in the brain for 10/10 (100.0%, 95% CI: 69.2% to 100.0%) F, T, and BE heads. In heads that could reliably be assessed for BD, BD was detected in 10/10 (100.0%, 95% CI: 69.2% to 100.0%) F heads, 9/9 (100.0%, 95% CI: 66.4% to 100.0%) T heads, and 0/10 (0.0%, 95% CI: 0.0% to 30.1%) BE heads. For boars, the bolt path was in the plane of the brain for 8/9 (88.9%, 95% CI: 51.8% to 99.7%) F heads, 9/10 (90.0%, 95% CI: 55.5% to 99.7%) T heads, and 11/11 (100.0%, 95% CI: 71.5% to 100.0%) BE heads. In heads that could reliably be assessed for BD, BD was detected in 8/9 (88.9%, 95% CI: 51.7% to 99.7%) F heads, 7/10 (70.0%, 95% CI: 34.8% to 93.3%) T heads, and 4/11 (36.4%, 95% CI: 10.9% to 69.2%) BE heads. Tissue depth was reported as mean ± SE followed by 95% one-sided upper reference limit (URL). For sows, total tissue thickness differed (P < 0.05) between placements (F: 49.41 ± 2.74 mm, URL: 70.0 mm; T: 62.83 ± 1.83 mm, URL: 76.6 mm; BE: 84.63 ± 3.67 mm; URL: 112.3 mm). Total tissue thickness differed (P < 0.05) between placements for boars (F: 54.73 ± 3.23 mm, URL: 77.6 mm; T: 70.72 ± 3.60 mm, URL: 96.3 mm; BE: 92.81 ± 5.50 mm; URL: 135.3 mm). For swine between 120 and 200 kg BW, the F placement may have the greatest likelihood for successful euthanasia due to the least total tissue thickness and may present less risk for failure than the T and BE placements.
Euthanasia is an important procedure to protect animal welfare and cannot be avoided on swine farms. A common method of euthanasia for swine is penetrating captive bolt (PCB), which involves passing a metal bolt through the skull into the brain. This process should result in an immediate loss of consciousness. The use of PCB has been evaluated for market hogs and heavier sows and boars, but not for sows and boars weighing < 200 kg. As pigs mature, the cranial thickness at the common frontal PCB placement increases due to the expansion of sinus cavities. This makes PCB euthanasia more challenging for sows and boars. As a result, alternative PCB application sites, including behind the ear and at a temporal location, have been proposed. This study evaluated frontal, temporal, and behind-ear placements for PCB application to cadaver heads from sows and boars weighing < 200 kg. The frontal placement appeared to be more reliable than the temporal or behind ear placements due to the least tissue for the bolt to travel through to reach the brain, the greatest potential target area, and prevalent brain damage.

The main objective of this study was to describe tissue thicknesses of cadaver heads from physically castrated market barrows (PC MARKET BARROWS) and immunocastrated boars (IC BOARS) at the frontal penetrating captive bolt (PCB) placement. Other objectives were to describe differences in bolt force and energy requirements to penetrate and describe potential for bolt-thalamus contact. Forty-four heads were obtained from PC MARKET BARROWS (n = 22) and IC BOARS (n = 22) of similar age and size that were rendered insensible with CO2. Mean HCW was 117.32 ± 3.52 kg. Snout to poll distance (cm) and maximum deflection distance (cm) were collected in duplicate. Heads were split at midline with a bandsaw and soft tissue and cranial thicknesses were measured with a digital caliper. Images of each cut surface were collected to evaluate the potential for thalamic damage. Tissue samples were retained from each half of each head and a universal tester was used to determine maximum force and energy of bolt penetration. There was no evidence to support a significant difference (P > 0.05) in tissue thicknesses between PC MARKET BARROWS and IC BOARS. Maximum deflection distance (maximum distance from a straight edge that was placed from the tip of the snout to the poll of the head) was not different (P = 0.10) between PC MARKET BARROWS (3.31 ± 0.10 cm) and IC BOARS (3.08 ± 0.10 cm). There was no evidence to support a difference (P = 0.77) in maximum force between PC MARKET BARROWS (7130.32 ± 483.23 N) and IC BOARS (6974.60 ± 463.70 N). There was also no evidence to support a difference (P = 0.62) in maximum energy between PC MARKET BARROWS (33.37 ± 2.77 J) and IC BOARS (32.04 ± 2.50 J). For PC MARKET BARROWS, there was a difference (P = 0.05) between the number of heads where the thalamus was located within the theoretical plane of bolt travel for market placement (21/21) versus mature placement (16/21). For IC BOARS, the number of heads where the thalamus was located within the plane of theoretical bolt path was not different between the two PCB placements (19/21 each). Overall, the data suggest that tissue profiles of PC MARKET BARROWS and IC BOARS do not differ at the frontal PCB placement site and the mechanical tools that are effective for PC MARKET BARROWS should also be effective for IC BOARS.

To determine the humane use of slaughter methods we examined the clinical signs of life in 61 American alligators harvested on-farm using one of three methods: (i) captive bolt and spinal cord severance; (ii) electrostunning, spinal cord severance and pithing; and (iii) spinal cord severance and pithing. Loss of consciousness and the six clinical signs of life that can be used on-farm were assessed for evidence of irreversible unconsciousness and death at Time 0, 0.5, 1, 2, 5, 10, 20, and 30 min post slaughter. The brains of alligators from each slaughter method were removed to assess brain tissue disruption. A combination of loss of blink reflex, pupillary light response, jaw tone and respiration are a reliable on-farm tool for determining death. Heartbeat and withdrawal reflex persisted. Captive bolt and electrostunning methods were effective in immediately producing loss of response consistent with irreversible unconsciousness, subsequent death and destruction of neural tissue integrity in the mid and hind brain. They are therefore humane forms of slaughter in American alligators.

The definition of animal welfare includes how an animal dies. As such, euthanasia is intrinsically linked to animal welfare, and ensuring a good death through effective, safe, and validated practices is a critical piece of promoting positive animal welfare. The objective of this review is to provide a better understanding of the literature on the euthanasia of swine via penetrating captive bolt (PCB) and nonpenetrating captive bolt (NPCB), as well as a history of captive bolt use, and indicators of sensibility and insensibility. To do this, we performed a systematic review that included 30 peer-reviewed articles and 17 other publications. NPCB devices have been validated as an effective single-step euthanasia method for neonatal and preweaning swine, as well as a two-step euthanasia method for nursery swine. PCB devices have been validated as an effective euthanasia method for nursery and market swine up to 120 kg, but further investigation is required for the use of captive bolt devices on mature breeding sows and boars.

Three penetrating captive bolt (PCB) placements were tested on cadaver heads from swine with estimated body weight (BW) >200 kg (sows = 232.9 ± 4.1 kg; boars = 229.3 ± 2.6 kg). The objectives were to determine tissue depth, cross-sectional brain area, visible brain damage (BD), regions of BD, and bolt-brain contact; and determine relationships between external head dimensions and tissue depth at each placement. A Jarvis PAS-Type P 0.25R PCB with a Long Stunning Rod Nosepiece Assembly and 3.5 g power loads was used at the following placements on heads from 111 sows and 46 boars after storage at 2 to 4 °C for ~62 h before treatment: FRONTAL (F)-3.5 cm superior to the optic orbits at midline, TEMPORAL (T)-at the depression posterior to the lateral canthus of the eye within the plane between the lateral canthus and the base of the ear, or BEHIND EAR (BE)-directly caudal to the pinna of the ear on the same plane as the eyes and targeting the middle of the opposite eye. For sows, the bolt path was in the plane of the brain for 42/42 (100%, 95% confidence interval [CI]: 91.6% to 100.0%) F heads, 39/40 (97.5%, 95% CI: 86.8% to 99.9%) T heads, and 34/39 (87.5%, 95% CI: 72.6% to 95.7%) BE heads; for the heads that could reliably be assessed for BD damage was detected in 25/26 (96.2%, 95% CI: 80.4% to 99.9%) F heads, 24/35 (68.6%, 95% CI: 50.7% to 83.2%) T heads, and 5/40 (12.5%, 95% CI: 4.2% to 26.8%) BE heads. For boars, the bolt path was in the plane of the brain for 17/17 (100.0%, 95% CI: 80.5% to 100.0%) F heads, 18/18 (100.0%, 95% CI: 81.5% to 100.0%) T heads, and 14/14 (100.0%, 95% CI: 76.8% to 100.0%) BE heads; damage was detected in 11/12 (91.7%, 95% CI: 61.5% to 99.8%) F heads, 2/15 (13.3%, 95% CI: 1.7% to 40.5%) T heads, and 7/14 (50.0%, 95% CI: 23.0% to 77.0%) BE heads. Tissue depth was reported as mean ± standard error followed by 95% one-sided upper reference limit (URL). For sows, total tissue thickness was different (P < 0.05) between placements (F: 52.7 ± 1.0 mm, URL: 64.1 mm; T: 69.8 ± 1.4 mm, URL: 83.9 mm; BE: 89.3 ± 1.5 mm, URL: 103.4 mm). In boars, total tissue thickness was different (P < 0.05) between placements (F: 41.2 ± 2.1 mm, URL: 56.3 mm; T: 73.2 ± 1.5 mm, URL: 83.4 mm; BE: 90.9 ± 3.5 mm, URL: 113.5 mm). For swine > 200 kg BW, F placement may be more effective than T or BE due to less soft tissue thickness, which may reduce concussive force. The brain was within the plane of bolt travel for 100% of F heads with BD for 96.2% and 91.7% of F sow and boar heads, respectively.

On-farm euthanasia of poultry is a necessity for minimizing disease spread and removing sick or injured birds to maintain optimum animal welfare. There are numerous methods that are approved for euthanasia of poultry by organizations like the American Veterinary Medical Association; however, all approved methods are not easily carried out on-farm or as effective as one another. Therefore, the objective of this study was to compare several captive bolt devices (Turkey Euthanasia Device, Zephyr-EXL, Jarvis Stunner, Experimental Crossbow), mechanical cervical dislocation (Broomstick method [BRM] and Koechner Euthanasia Device [KED]), and manual cervical dislocation (MAN) methods on 8 and 12-week-old turkey hens. Each method was assessed for impact on loss of brain stem reflexes, euthanasia success, and torn skin. The cervical dislocation techniques were also analyzed via radiograph for proper dislocation. Furthermore, each device was assessed for physical parameters. Turkeys (n = 1,400) were euthanized on 20 sampling days, 10 sampling days for each age period. All methods resulted in euthanasia of all turkeys in this study. The captive bolt devices all resulted in immediate loss of nictitating membrane and pupillary reflex at both the ages tested. The cervical dislocation methods differed in both nictitating membrane and pupillary reflex cessation at both ages (P < 0.05). The pattern was the same at both ages with the KED device have longer latencies to cessation of both reflexes when compared to the BRM and MAN methods (P < 0.05). Cessation of movement was also generally longer in dislocation methods compared to captive bolt at both ages. However, captive bolt devices resulted in more lacerations of the skin in general. MAN was also found to result in less damage to the vertebrae and proper location of separation than the mechanical methods of dislocation. All methods resulted in effective euthanasia; however, captive bolt methods resulted in immediate loss of brain stem reflexes indicating that they maybe more humane than cervical dislocation methods.