Pairwise comparison locomotion scoring for dairy cattle

• Published in: Journal of dairy science Vol. 104; no. 5; pp. 6185 - 6193
• Main Authors: Gardenier, John, Underwood, James, Weary, D.M., Clark, C.E.F.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.05.2021
• Subjects: Animals; Cattle; Cattle Diseases; gait assessment; lameness; Lameness, Animal - diagnosis; Locomotion; observer consistency; Observer Variation; pairwise scaling; Reproducibility of Results; observer consistency; lameness; pairwise scaling; gait assessment
• ISSN: 0022-0302; 1525-3198
• DOI: 10.3168/jds.2020-19356

Conventional locomotion scoring is a subjective, absolute, and discrete assessment of locomotion. Here we assess pairwise comparison scoring to improve upon the limited intra- and interobserver consistency typical of conventional locomotion scoring. Five observers performed conventional 4-level locomotion scoring using 50 video recordings of dairy cattle, and also assessed 90 pairs of videos (composed from the same 50 recordings) using relative pairwise scoring. Intra- and interobserver consistency of pairwise scores [intraobserver: percentage agreement (PA) = 82%, κ = 0.63; interobserver: PA = 79%, κ = 0.57] were greater than of 4-level absolute scores (intraobserver: PA = 72%, κw = 0.74; interobserver: PA = 56%, κw = 0.59). Pairwise scores were scaled with an optimization method to obtain the position of the 50 recordings on a continuous locomotion scale. These continuous locomotion scores (CLS) were compared with the conventional mean absolute visual locomotion scores (VLS). Correlation between CLS and VLS was strong (τ = 0.69), and consistency between binarized CLS and binarized VLS was high (PA = 84%, κ = 0.66 for threshold VLS ≥1). Just noticeable difference (JND) for locomotion scoring was 0.3 on a 4-level scale ranging from 0 to 3. Pairwise scoring and scaling had the scoring consistency of binary absolute scoring with finer continuous granularity than 4-level absolute scoring. The pairwise scoring method, and associated scaling, offer a more consistent and informative alternative to conventional absolute multilevel locomotion scoring.