Variations in the Structure of Bleats From Sheep of Four Different Breeds

Abstract

Abstract Characteristics of bleats from groups of ewes from Clun Forest, Dalesbred, Jacob and Border Leicester breeds are described. The bleats were analysed on a sonagraph and measured for length, fundamental frequency and formant structure. The bleats from Border Leicester sheep differed most from the other breeds, they were the longest bleats and had the lowest fundamental frequency with four formants in a pattern 4-10-14-17. Clun Forest ewes had the shortest bleats and highest fundamental frequency, with three formants in a pattern 3.6-8-12. Jacob bleats showed little variation in fundamental frequency and were lower than Dalesbred and Clun bleats. They sounded rich and mellow and often had only two formants in a pattern of 4-9 (sometimes 12). Dalesbred bleats were long and vigorous with well marked harmonics. Their formant pattern was 4-9-13. Individual ewe's bleats had a combination of characteristics which were different from bleats of other sheep. Lambs do not seem to use any one particular character of the bleat to identify the voice of their dam.