Sound analysis in dairy cattle vocalisation as a potential welfare monitor

In modem farming there is a growing demand for innovative tools gathering and analysing information concerning the herd, as well as individual animals. In Precision Livestock Farming (PLF), technology continuously measures various variables as activity, food intake or oestrus activity, thereby supporting farmers in monitoring his livestock. Sound analysis has shown to be useful as an early warning tool in pigs and it is unknown whether sound analysis can also be applied in cattle. Goal of this research was to determine whether a correlation can be found between cattle vocalisation and cattle behaviour. The vocalisations and behaviour of Holstein Friesian cattle were observed using audio and video recordings. Four cameras and four microphones were installed at a high production dairy farm in Herwijnen, the Netherlands. Three sets (a set consisting of both a camera and a microphone) recorded dairy cattle between two and fourteen years of age, one set recorded heifers between four and ten months of age. Recordings were made for fifteen days in three consecutive weeks, ten hours per day. Calls of cattle were traced to an individual cow and, if possible, linked with simultaneously expressed behaviour. The used ethogram consisted of six behavioural groups: lying & ruminating, feeding related behaviour, social interaction, sexual related behaviour, stress related behaviour and remaining behaviour. Lying & ruminating was a separate class since this behaviour expresses the needs of a cow. The maximum frequency in Hertz (Hz) of each call was determined. Statistical analysis showed a significant difference between the mean maximum frequency (Hz) of calls during lying & ruminating and calls recorded during other behaviours (83 +/- 4.3 Hz versus 298 +/- 8.0 Hz; p < 0.05). Calls by adult dairy cattle had a significantly lower maximum frequency (Hz) than calls by heifers. (332.6 +/- 0.2 Hz versus 218.5 Hz 0.3 Hz; p < 0.05). This study may provide a foothold towards the use of sound analysis as a tool for dairy cattle management. If calls by cattle can be used to monitor welfare, dairy farmers can be alerted when cattle welfare is decreasing. (C) 2015 Elsevier B.V. All rights reserved.