The effect of nutrition on skin and skinfold thickness in cattle.

Abstract

The Effect of Nutrition on Skin and Skinfold Thickness in Cattle N. M. TULLOH Interest in skin thickness of cattle has been concerned mainly with its physiological significance in relation to the adaptation of animals to tropical and subtropical environments. However, as the skin of an animal represents its most accessible tissue, it is also worthy of study in relation to the effect of nutrition on body cornposition in more temperate environments. The object of this experiment was to determine the effect of plane of nutrition on skin and skinfold thickness in Melbourne, Victoria (L,at. 37' 50'S.) Eight Hereford steers aged 18 months were housed in individual stalls in March 1959. Three weeks later on April 15th the experiment started when three animals were placed on a high plane of nutrition (group A), two on maintenance rations (group B) and three on a low plane of nutrition (group C). Ten weeks later (June ` 23rd) the planes of nutrition were reversed, group A being placed on a low plane, group B remaining on a maintenance ration, and group C on a high plane. Six weeks later (August 4th) the experiment ended. The cattle were weighed weekly. Skinfold measurements were made every fortnight on the left midside, on an area prepared by surgical clipping, using dial gauge callipers. Two adjacent biopsy skin samples were taken from the midside of each animal, using the method described by Dowling (1955) on each of the following occasions :-April 15, June 23, August 4. Samples were placed in 1 per cent. formol-saline and, after trimming to remove subcutaneous fat and muscle, skin thickness was measured using a Mercer dail micrometer model 131. To minimise errors due to shrinkage all samples were measured at the same age. The results are given in Table I. The live weight changes obtained were substantial, and were regarded as satisfactory. During the first part of the experiment group A (high plane) showed an increase in skinfold thickness (1.1 mm.), but all other changes in skinfold thickness were small. Groups A (high plane) and C (low plane) both showed increases in skin thickness (1.8 mm and 1.0 mm. respectively during the first part of the experiment, and as with r;kinfold thickness all other changes in skin thickness were small. The animals were in store condition when the experiment started and the increase in skinfold thickness of group A (high plane) compared with group B (maintenance) and C (low plane) during the first part of the experiment could be attributed to the deposition of subcutaneous fat by group A during this period. However, some work by Tulloh (in press) shows that mid-side skinfold thickness is not related to depth of subcutaneous fat in cattle. It is more likely that this increase in skinfold thickness was due to the deposition of fat and protein in the skin. It may seem surprising that groups A (high plane) and C (low plane) both showed increases in skin thickness during the first part of the experiment. It is postulated that the increase in thickness obtained in the low plane group was due to the development of a nutritional oedema. In the second part of the experiment no important changes in skin or skinfold thickness were obtained, which suggests that for animals of the type used in the present work, changes in thickness are not particularly suceptible to changes in live weight. l School of Agriculture, University of Melbourne. 1 92 193 ACKNOWLEDGEMENTS The author wishes to thank the Royal Agricultural Society of Victoria for their courtesy and co-operation in providing facilities for this work at their Show Grounds, the Commonwealth Bank of Australia Rural Credits Fund for financial assistance, and Mr. R. McKenzie for technical assistance. REFERENCE Dowling, D. F. (1955) .-Aust. J. Agric. Res. 6: 645-654. DISCUSSION W. Stephens (Tas.) asked whether temperature had any effect on skin thickness. Answer.-This may be so. A clipped area showed a greater thickness than an unclipped area. The variability between different sites of the biopsy operation was extremly low. 194