Variations in the skin and skin-fold thickness of beef cattle.

Abstract

A series of successive skin-fold measurements were made on the midside area of Hereford, Angus, and Shorthorn steers of the same age reared together from birth until slaughter. Biopsy skin samples were taken from the midside area of these steers just before slaughter. An investigation of various sites of measurement showed that the skin over the midside area was relatively uniform in thickness. A Harpenden skin-fold calliper was used for skin-fold measurements. They were obtained without using a local anaesthetic, because it was found that any relaxation of the skin which an anaesthetic may produce was not detected with this instrument. The thickness of biopsy skin samples was measured with a Mercer dial micrometer No. 131. The correlation coefficient between skin and skin-fold measurements was 0.82. High correlations of skin and skin-fold thickness with fresh and dry weights of skin samples were obtained. A marked association of skin-fold thickness with age and with liveweight was found up to the age of 26 months. It appears that these changes in skin-fold thickness wese more closely related to liveweight than to age. Evidence is presented which indicates that there is probably a sex difference in skin-fold thickness, cows having thinner skins than steers. A significant correlation coefficient (r = 0.50) was found between the skin-fold thickness of steers and of their dams. Seasonal fluctuations in skin-fold thickness were obtained, which were independent of changes in liveweight. A thicker skin-fold measurement was obtained on areas which had been clipped regularly compared with areas which had not been previously clipped. Breed differences in skin and skin-fold thickness were obtained. The mean skin thickness for steers aged 26 months was: Hereford, 9.45 mm ¦ S.E. 0.20; Angus, 8.04 mm ¦ S.E. 0.16; Shorthorn, 6.85 mm ¦ S.E. 0.33. In a series of single observations just before slaughter, no relation was found between skin thickness and liveweight. Therefore it is unlikely that skin thickness is a useful criterion for selecting high growth rate animals in this environment.