Date Full Report Received


Date Abstract Report Received



Primary Investigator:

Pigs in the USA are routinely castrated without any pain relief. Castration is a painful procedure that results in short and long-term physiological and behavioral deviations of the piglet. Alleviating pain is important from a welfare perspective as it falls under one of the five freedoms of animal welfare. However, there are currently no FDA approved products specifically labelled to manage pig pain in the US. To gain FDA approval, a product must be shown to reduce pain in a target species utilizing validated methods of pain assessment. Behavior is a common measure used to assess pain but no behavioral sampling methodologies used to quantify castration pain have been validated. Therefore, the objectives of this study were to validate two different behavioral methodologies (scan sampling and time-interval sampling) to quantify piglet pain after castration. A total of 39 (scan sample) and 16 (time-interval sample) Yorkshire-Landrace × Duroc male piglets (five days of age) were surgically castrated using a scalpel blade. Behaviour frequency and duration of each piglet were collected continuously 24 priors to castration and 1, 8 and 24 hours post-castration. This continuous data was compared to scan sampling intervals (2-min, 3-min, 5-min, 10-min and 15-min) and time sampling intervals (5-min, 10-min, 15-min, 20-min, 30-min and 45-min) to determine if the sampling method accurately reflected true duration and frequency for each behavior using previously established criteria. No scan sampling interval provided accurate estimates for any pain behaviors while the 45-min time interval provided accurate estimates for the affiliative interactions, sitting, walking, huddled up, prostrated, scratching, spasms, and trembling behaviors. Results from this study suggest that scan sampling is not an appropriate method to evaluate pain behavior in piglets but a 45 min time sampling method can be used to investigate piglet behavior post-castration. The results from this study lay the ground-work in establishing validated methodologies. Future research and drug approval trials will likely need to utilize a multimodal approach to effectively and accurately evaluate pain behavior associated with castration.

Monique Pairis-Garcia
Associate Professor; Global Production Animal Welfare
Department of Population Health and Pathobiology
CVM Main Building, Room D344
1060 William Moore Drive
Raleigh, NC 27607
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