Modification and expansion of existing body condition scoring scales for rabbits (Oryctolagus cuniculus) improves...

Reliable body condition scoring in rabbits is essential in managing healthy bodyweight. The commonly used Rabbit size-o-meter (RSOM) has shown poor inter-rater reliability, particularly among inexperienced raters. This study aimed to develop a reliable, reproducible body condition scoring scale for companion rabbits across breeds, ages and sexes.

We evaluated the impact of rewording RSOM descriptors, expanding scales from five to nine points, and using single-point anatomical assessments on inter- and intra-rater reliability. Eleven raters from three rater groups (veterinary professionals, students and laypersons) gave 400 rabbits 3113 scores using nine modified scales. Ordinal mixed models assessed the effects of age, sex, rater group and scale on scores. Reliability was assessed using Krippendorff's alpha and Cohen's kappa.

Intra-rater reliability ranged from moderate to almost perfect (κ = 0.61‒0.92). Expanding to nine points improved overall inter-rater reliability (α = 0.60‒0.65), with inter-rater reliability being highest among experienced raters (α = 0.79). The revised nine-point scale with detailed descriptors achieved the highest inter-rater agreements. Single-point assessments showed low agreement (α = ‒0.32 to 0.62), except dewlap scoring by veterinary professionals (α = 0.77). Rater group and scale significantly affected scores, unlike age and sex.

Different rabbits were used across scale comparisons.

A revised nine-point scale modestly improved reliability for experienced raters, though not overall statistically significant.