Real-time and video-recorded pain assessment in beef cattle: clinical application and reliability in young, adult bulls undergoing surgical castration

Abstract

Bovine pain assessment relies on validated behavioral scales related to normal and pain-related behaviors. This study investigated the reliability and applicability of real-time and video-recorded pain assessment, and their agreement, in young, adult bulls undergoing surgical castration. Ten Nelore and nine Angus bulls underwent general anesthesia and surgical castration. Three-minute real-time observations and simultaneous videos were recorded at - 48 h (M0), before sedation, under fasting (M1), after surgery, 3 h after sternal recumbency (M2), after rescue analgesia (M3) and at 24 h (M4). Animals received morphine (after M2), dipyrone (after M3), and flunixin meglumine after surgical castration (M4). Two trained evaluators assessed real-time (n = 95) and video-recorded time-points (n = 95) using the Unesp-Botucatu Cattle Pain Scale (UCAPS). Both assessment methods inferred 'very good' reliability (≥ 0.81) with minimal bias, however, video-recorded assessment (4.33 ± 2.84) demonstrated slightly higher scores compared to real-time (3.08 ± 2.84). The results from this study suggest that UCAPS can be used in real-time or video-recorded to assess pain and guide analgesic therapy in cattle.

Figure 1

Plots of Unesp-Botucatu cattle pain scale (UCAPS) comparing time-points (A), assessment methods (B), interaction between moments, assessment methods (C), breed (D) and evaluators (E). The top and bottom box lines represent the interquartile range (25–75%), the line within the box represents the median, the extremes of the vertical lines represent the minimum and maximum values (mean ± 3 × standard deviation), black diamond represents the mean, black circles above or below the extremes of vertical lines represent outliers (above or below the mean ± 3 × standard deviation), different lowercase letters (a > b) indicate statistical difference (p < 0.05) between the time-points, while different capital letters (A > B) indicate difference (p < 0.05) between the assessment methods according to the multilevel zero-inflated Poisson model.

Figure 2

Bland–Altman plots comparing real-time and video-recorded assessment of the Unesp-Botucatu Cattle Pain Scale (UCAPS). LoA, limit of agreement; CI, 95% confidence interval; solid line represents the bias; dashed line represents the lower and upper LoA; dotted lines represent the 95% confidence interval; CCC, Lin's concordance correlation coefficient; green line is the simple linear model.

Figure 3

Timeline of the time-points used for the video-recorded and real-time pain assessment using the Unesp-Botucatu Cattle Pain Scale (UCAPS). Video recording was performed for 3 min at each time-point.