Acoustic features of vocalization during different phases of estrous cycle in Murrah buffaloes

The present study was conducted to investigate the changes in acoustic features of vocal signals articulated by Murrah buffaloes during different phases of estrous cycle. Data (voice) were collected from 20 Murrah buffaloes, maintained at Livestock Research Centre, NDRI, Karnal, during 4 phases of estrous cycle. Following acoustic features (call duration, formants, intensity, pitch, noise/harmonic (N/H) ratio, harmonic/noise ratio, number of periods, pulses, jitter, shimmer and unvoiced frame) were extracted from vocal signals of Murrah buffaloes for analysis purpose. The acoustic features, viz. call duration, fourth formant (F4), shimmer and intensity were significantly higher during proestrus phase as compared to other phases of estrous cycle. Whereas, F1, F5, noise to harmonic ratio, per cent unvoiced frames and pitch were significantly higher during estrus phase. All these features have significant correlation with estradiol hormone during proestrus and estrus phase. The other features namely number of periods and pulses were significantly correlated with progesterone hormone during diestrus phase. Therefore, the acoustic features, viz. F1, F5, N/H ratio and unvoiced frame can be utilized for identification of estrus phase in Murrah buffaloes.