Effects of assessment method (real-time versus video-recorded) on a validated pain-altered behavior scale used in castrated piglets

Abstract

We aimed to compare two assessment methodologies (real-time vs. video-recorded) using the Unesp-Botucatu Pig Composite Acute Pain Scale (UPAPS) in piglets before and after castration. Twenty-nine male piglets were castrated. Four observers scored the UPAPS over three perioperative timepoints of castration following two assessment methodologies. In real-time assessments, the observers were in-person observing the piglets in front of the pen. After two weeks, the observers did video-recorded assessments randomizing piglets and timepoints. Modeling was conducted to compare the UPAPS and each pain-altered behavior between methodologies. Intraclass correlation coefficient (ICC), Bland-Altman, and Lin's concordance correlation coefficient (CCC) were conducted to investigate agreement between methodologies. UPAPS was statistically equivalent between methodologies (P = 0.4371). The ICC for each method was very good (0.85 to 0.91). The agreement of the UPAPS assessed between methodologies had minimal bias (- 0.04), no proportion bias, and 53% of the assessments presented a perfect agreement. However, CCC of the UPAPS was moderate (0.65), and only one pain-altered behavior ("presents difficulty in overcoming obstacles or other animals") occurred more in real-time assessments (P = 0.0444). In conclusion, piglet pain assessment by UPAPS can be conducted in real-time based on a suitable agreement between the real-time and video-recorded assessment methods.

Figure 1

Plots of Unesp-Botucatu Pig Composite Acute Pain Scale (UPAPS) comparing timepoints (A) and assessment methods (B) (diamond is the mean; different lowercase letters (a > b) indicate statistical difference based on the post-hoc test from multilevel zero-inflated negative binomial model).

Figure 2

Bland–Altman test of Unesp-Botucatu Pig Composite Acute Pain Scale (UPAPS) assessed in real-time and video-recorded method (LoA is limit of agreement; CI is 95% confidence interval; solid line is the bias; dashed line is the lower and upper LoA; dotted lines is the 95% confidence interval for bias and 90% confidence interval for lower and upper LoA; CCC is Lin’s concordance correlation coefficient; green line is the simple linear model).