Physiological Response of Lambs to Auditory Stimuli

Abstract

Three hundred thirty observations on 10 Suffolk ewe lambs were used to determine auditory thresholds for sheep. Tests were conducted using a free-field technique in a semi-soundproofed room (background 26 dB). EEG pattern changes and behavioral responses used to determine hearing thresholds correlated highly (r=0.95). Animals tested were most sensitive (lowest threshold) at 7,000 Hz. The resulting audiogram was similar in shape to that for humans but at a higher frequency. Heart and respiratory rates were measured in lambs exposed to different types and levels of noise. Differentiation to both sound type and sound level was apparent, as was acclimation to sound.