The influence of sex on muscle growth in Merino sheep
Lohse, C.L.
Growth 37(2): 177-187
1973
ISSN/ISBN: 0017-4793 PMID: 4743995 Document Number: 58443
At birth, 64 Peppin Merino sheep were segregated according to sex and pastured throughout life on the New England tablelands of Australia. Sheep were slaughtered in a series of 8 age groups ranging from 1 day to 2 yr. Each carcass was completely dissected and the individual muscles weighed. Muscle growth coefficients and their standard errors were computed from weight data, and growth patterns of 96 muscles and 10 muscle groups classified. 25 muscles and 3 muscle groups of ewes received different classification than those of rams. Influences of sex were indicated by greater muscle growth rates for neck muscles of rams. Classification of muscle growth patterns differed between rams and ewes for 3 muscle groups. Muscles of the proximal pelvic limb in the ewes reached a growth plateau earlier than in rams. Two other muscle groups received higher classifications for rams in later phases of neck and thorax muscle growth. It was concluded that heavy neck muscles of older rams could have an adverse effect on carcass muscle distribution. Comparative similarities in neck and crest development for bulls and rams from growth of a specific neck muscle, the splenius cervicis muscle, are discussed.