Relationship and repeatability of body condition scoring and backfat thickness measurement in dairy cows by different investigators

The determination of the body condition of dairy cows is a helpful instrument to assess the energy situation of individual cows and herds. Two methods for determining the body condition are well established in bovine practice, body condition scoring (BCS) and measurement of backfat thickness (BFT). The objectives of this study were to evaluate the repeatability of BCS on a five-point scale with 0.25-points increments and the measurement of BFT by ultra-sound (5 MHz linear probe) as well as the repeatability of measuring BFT at both sides of the cows back. Five investigators with different experience with BCS and BFT assessed a total of 94 cows repeatedly, resulting in 1806 BCS-measurements and 1723 (left) and 1733 (right) BFT-values. Weighted kappa coefficient was used to evaluate the agreement of repeated measurements and correlations were calculated for linear associations. Within-observer agreement of BCS and BFT was good for both methods (K = 0.67 and 0.78, respectively). Agreement was moderate to substantial for BCS and BFT depending on the investigator. Within-observer agreement of BFT at the right and left body side was substantial (K = 0.75). There was a high correlation between repeated measurements of BCS and BFT (r = 0.93 and r(C) = 0.91, respectively), and between BFT measured at the left and right body side (r(C) = 0.90). The correlation between BCS and BFT Was moderate (r = 0.67). Overall, both methods demonstrated good repeatability applied by different investigators. In summary, BCS and BFT measurements are practical tools to contribute beneficially to herd health management.