Acoustic Features of Pain-Induced Vocalisations Are Associated with Subsequent Growth and Temperament Following...

Whether vocalisations during disbudding predict later outcomes in goat kids is unknown. In this preliminary study, we allocated 18 female Tianfu goat kids to disbudding (n = 9) or sham (n = 9). Disbudding used a hot iron without analgesia; sham kids received an unheated iron. Vocalisations, tail flicks, and struggles were recorded. Fundamental frequency (F0) and Mel-frequency cepstral coefficients (MFCCs) were extracted. Body weight and temperament were assessed at 90 days post-procedure; home-pen behaviour was scan-sampled at 60 and 90 days post-procedure. Two kids were excluded due to insufficient recordings, leaving 16 (9 disbudded, 7 sham). Disbudded kids vocalised more frequently (14.5 vs. 8.1 calls/min, p = 0.0007) and had lower minimum F0 (283.4 vs. 366.1 Hz, p = 0.020), with significant MFCC shifts. Several acoustic features correlated with body weight at 90 days post-procedure (mfcc_12_std: r = 0.903, p = 0.001) and temperament (mfcc_2_mean: r = -0.788, p = 0.012) after controlling for disbudding weight. The first principal component of acoustic features (PC1) correlated with lower body weight at 90 days post-procedure in disbudded kids (r = -0.786, p = 0.036), but not in shams (r = -0.257, p = 0.623). No subgroup differences were found in home-pen behaviours. These findings indicate that acute pain vocalisations may reflect individual stress reactivity-a possible 'vocal phenotype'-and, with validation, could inform non-invasive screening for at-risk kids.