The first-ever auditory testing of dairy cows in South Africa recently took place at the Hillcrest Experimental Farm. The results of this test hold the potential to further our understanding of noise pollution and the improvement of cow comfort and well-being.
The dairy cows on the Hillcrest farm are exposed to different kinds of environmental noises, including normal farm sounds such as the milking machine in the parlour or feed wagon and other external noise. Cows react to their environment based on all five senses, including hearing. How they perceive and evaluate their environment strongly impacts their well-being.
Cows have an excellent hearing with a sound pressure threshold of between 85 and 90 dB. A multi-disciplinary team consisting of Dr Alida Naude and Prof Juan Bornman (both from the Centre for Augmentative and Alternative Communication), Prof Esté van Marle-Köster and Ms Lize Erasmus (both from Department of Animal Science) and Ms Simone Zevenster (an audiologist) decided to test the hearing of the Holstein cows using Brainstem Auditory Evoked Response (BAER) technology.
BAER is a reliable method to determine hearing thresholds. It is non-invasive and provides an objective assessment that does not require any voluntary response from the cow to indicate a perception of sound. After the University of Pretoria granted ethical approval, BAER was used to test the hearing of 10 cows with the assistance of Dr Liesl de Swardt, a veterinary surgeon.
Hearing thresholds, wave latencies and interpeak latencies using BAER were recorded using a click as the sound stimulus during this study. The responses had good repeatability with low variation among the cows. All Hillcrest cows had good hearing with 85 dB SPL determined as the lowest level of hearing in the high frequencies, with clear and repeatable responses for neurological analysis of the auditory pathway at a stimulus level of 105dB SPL. To our knowledge, this was the first auditory testing of dairy cows in South Africa and holds the potential to further our understanding of noise pollution and improvement of cow comfort and well-being.
From left: Dr Liesl de Swardt, Dr Alida Naude, Prof Juan Bornman, Ms Lize Erasmus, Ms Simone Zevenster and Prof Este van Marle-Köster.