Cough sound description in relation to respiratory diseases in dairy calves

Cough can be a biomarker in case of respiratory diseases. By monitoring and analyzing cough sounds through automatic devices, the farmer can obtain an early warning about a developing outbreak of respiratory infections. Cough sounds can be characterized by particular acoustic features (amplitude, frequency and duration) that are obtained by sound recording, labeling and analytic procedures. Based on these features, it might be possible to develop an automated cough recognition system. The aim of the study described in this paper is to investigate whether it is possible to discriminate cough sounds from other frequently occurring sounds in youngstock stables. Nasal swabs and blood were taken to identify the microbiological agents responsible for the respiratory problems. The collected cough sounds were compared to metal rack sounds, which are very common sounds in cattle farming, to identify acoustic differences between them. Results show that the length of cough sounds was significantly different from metal rack sounds (0.34 versus 0.37 s, P < 0.05). Also, the analysis of amplitude and fundamental frequency showed significant differences between both types of sounds (resp. 0.21 and 0.18; 1326 and 3868 HZ). This indicates that it is possible discriminate cough sounds from other sounds and that cough sound can be used as a non-invasively diagnostic tool for respiratory diseases in youngstock groups.