Development of an index based on ultrasonographic measurements for the objective appraisal of body condition in Andalusian horses

Body condition scoring (BCS) is an indirect measure of the level of subcutaneous fat; however, by measuring the subcutaneous fat thicknesses (SFT), the precision of the degree of fatness assessment is improved. The aims were: 1) to develop an alternative body fat scoring index (BFSI) based on ultrasonographic measurements; 2) to assess the agreement between BCS and the new index applied to Andalusian horses; 3) to adjust the BCS cut-off values (if necessary) for overweight and obesity in this breed. One hundred and sixty-six Andalusian horses were included in this cross sectional study. On each horse, BCS, body fat percentage (BF%) and ultrasonography of SFT at localized deposits were evaluated. According to BFSI five possible body categories were established. Only one horse (0.6%) was classified as emaciated, 9.0% as thin, 74.7% as normal, 11.4% as overweight and 4.2% as obese. Despite higher BCS and SFT values were observed compared to other breeds, most of the horses evaluated presented a normal body condition under the new BFSI. BCS and BFSI were significantly associated (p<0.001), however, the concordance was low (weighted Cohen’s kappa coefficient, 0.262 ± 0.071; p=0.004). Using BFSI, obese horses had significantly greater BF% than the rest of categories (p<0.001). BCS showed a good diagnostic accuracy for detection overweight (AUC = 0.759 ± 0.055; p<0.001) and obese (AUC = 0.878 ± 0.050; p=0.001) horses; redefining the cut-off values for overweight and obesity condition as 7.5/9 and 8.5/9 respectively in Andalusian horses