#20-097

Complete

Category

Date Full Report Received

09/30/2020

Date Abstract Report Received

09/30/2020

Investigation

Institution:
Primary Investigator:

Funded By

Euthanasia of mature swine is challenging given distinct age, sex and skull variations. As pigs age, the thickness of the skull increases, the frontal sinuses expand, and some breeds may develop a distinct bony ridge on the midline of the forehead (Anderson et al., 2019), making it difficult to cause enough trauma to the brain using a penetrating captive bolt gun when placed in a frontal location above the eyebrows of the pig. Identification of alternative locations for captive bolt gun placement are needed. Therefore, the objective of the present study was to evaluate the efficacy of two alternative locations (temporal and behind-the-ear) using a cylinder and pistol style captive bolt gun in boars and sows. Efficacy of the gun was determined by number of animals that achieved death and evidence of trauma and injury to the brain. Of the six initial treatments evaluated, four treatments were successful in sows and two treatments were successful in boars. When evaluating treatment success by sex, the cylinder gun was 100% effective in achieving death when applied to all locations for sows while the pistol gun was only 100% effective when applied at the behind-the-ear location for sows. For boars, the cylinder gun was 100% effective when applied to the frontal and behind-the-ear location, but the pistol gun was not effective for any location in boars. In addition, boars tended to have less trauma to the brain compared to sows and the cylinder gun produced greater trauma and hemorrhage to the brain than the pistol style gun. The results reported in the present study highlight the challenges associated with the euthanasia of mature swine. Several treatment combinations proved ineffective and are likely due to ineffective penetration and greater skull thickness of the boar. Despite the small sample size, data presented may serve as a baseline for future sample size calculations for studies of this type. Ideally, more work is needed to validate these alternative locations in mature sows and boars and how to best apply these techniques on a commercial farm setting.
Key Findings:
• Euthanasia treatments were more successful in sows compared to boars and is
likely a result of increased skull thickness in boars
• Cylinder style equipment produced greater trauma regardless of cranial location
for both boars and sows
• More work is needed to validate these alternative locations in mature sows and boars and how to best apply these techniques on a commercial farm setting