Vocalization as a measure of welfare in slaughter pigs at Danish slaughterhouses

摘要

Documentation of animal welfare in the entire production chain is an increasing demand from authorities and the market. One possibility of monitoring welfare at the slaughterhouse could be to measure the sound produced by the pigs, and correlate the sound to the corresponding behaviour and thereby use these measurements as an estimate of animal welfare. The aim of this study was to describe typical pig vocalizations at slaughterhouses and afterwards correlate them with the actual behaviour.Vocalizations were recorded during visits to three Danish slaughterhouses. Fifty different sound tracks were initially identified. By ear, nine different vocalizations have been identified and selected in the slaughterhouses as the most common vocalizations: Gruht, deep grunt, complaining, startled, 'go away', short/middle/long scream and squeal. Afterwards, three plots were made per vocalization: Amplitude plot as a function of time; power spectrum as a function of frequency; spectrogram made from 10 ms windows. Data from the power spectrum were analysed by multivariate analyses in order to find correlations between the vocalizations.It was concluded that it is possible to discriminate between various vocalizations at slaughterhouses by sound measurements. This is the fundament for a continuous monitoring of animal welfare using sound measurements at the slaughterhouse. However, much more work is needed to implement sound measurements as a tool for welfare documentation in practice.