ABSTRACT. aspect is very sparse and in view of its importance. MATERIALS AND METHODS

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1 MICROMETRICAL STUDIES ON THE SKIN OF MADRAS RED SHEEP (OVIS ARIES) IN DIFEERENT AGE GROUPS Mir Shabir Ahmad 1, O.R. Sathyamoorthy 2, Geetha Ramesh 3 and C. Balachandran 4 Department of Veterinary Anatomy and Histology, Madras Veterinary College, Chennai ABSTRACT Micrometrical studies on the skin of Madras red sheep was conducted in neonatal, young and adult age groups. The skin was the thickest on the neck dorsal region and thinnest on the thorax ventral region, in all the age groups studied. The epidermis on the dorsal regions was found to be slightly thicker than the lateral and ventral regions of neck, thorax and loin. From neonatal to adult age group animals, the dermal thickness was found to be increased in all the regions in the present study. The diameter of primary hair follicle was more than the secondary hair follicle and also the location of primary hair follicle was deeper to secondary hair follicle. Keywords: Skin, Micrometry, Sheep INTRODUCTION India s share of sheep skin is 6.69 per cent of the total world production. The skin has considerable economic value with regards to the leather, fur and wool industries (Konig and Liebich, 2004). The skin is an effective barrier which prevents desiccation of electrolytes and macromolecules from the body (Dyce et al., 2002). In mammalian skin, collagen is the most abundant structural constituent of the dermis, comprising about three quarters of the dry weight of this part of the integument. The collagen reacts with tanning agents to form the leather substances. The number of elastic fibres present in papillary layer is also important for leather production. The present study was aimed to investigate the micrometry of the skin of Madras red sheep as the literature in this aspect is very sparse and in view of its importance. MATERIALS AND METHODS The skin samples for this study were collected from the corporation slaughter house, Perambur, Chennai. Skin samples were collected from neonatal (1-2 months), young (3-9 months) and adult age groups (1 to 2 years). In each age group, six animals were utilized for the present research work. Immediately after slaughtering the animals, tissues were collected from eight regions namely neck dorsal, neck lateral, neck ventral, thorax dorsal, thorax lateral, thorax ventral, loin dorsal and loin lateral and were fixed in 10 per cent neutral buffered formaldehyde, Bouin s fluid, Zenker s fluid and Part of the M.V.Sc. thesis of the 1 st author submitted to the Tamil Nadu Veterinary and Animal Sciences University, Chennai Associate Professor 3. Professor and Head 4. Professor and Head 23

2 formal saline (Luna, 1968). By using ocular micrometer, thickness of skin, epidermis and dermis, and depth of primary hair follicles were measured in all the three age groups and in all the regions of skin in the present study. Arithmatic mean and standard error were calculated, tabulated and the statistical analysis of data was done as per Snedecor and Cochran (1994). 24 RESULTS AND DISCUSSION The thickness of the skin varied among the regions and different age groups studied. The thickness of skin was found to be maximum on the neck dorsal region and was minimum on the thorax ventral region in all the age groups studied. This was in total agreement with Tripati et al. (1996) in goats and Aslan et al. (2004) in cattle. However, Sharma and Bharadwaj (1993) observed that the thickest skin on the ventral aspect of neck in yak, but dorsum of the trunk was thicker than the ventral. Genkovski and Gerchev (2007) reported that in Tsigai ewes, the total skin thickness ranged from mm to mm. Abbasi et al. (2008) observed that the total skin thickness is 2.4 mm in Lori sheep. The thickness of skin had increased as age advanced (Table 1) as reported by Saxena et al. (1994) in cattle. Thickness of skin increased rapidly from neonatal age to young than from young to adult age. In neonatal animals, there was no significant difference (P < 0.01) in the thickness of skin of various regions studied (Table 1). In young animals, there was no significant difference in the thickness of skin among loin dorsal, loin lateral and neck lateral regions, there was also no significant difference in thickness of skin between neck ventral and thorax ventral regions. In adult animals, there Micrometrical studies on the skin... was no significant difference among neck ventral, thorax lateral, thorax ventral and loin lateral regions, between the thorax dorsal and loin dorsal regions, thickness of skin did not vary significantly. The thickness of epidermis varied among all the regions. The epidermis on the dorsal regions of neck, thorax and loin was found to be slightly thicker than the lateral and ventral regions which were similar to the reports of Bhayani et al. (1995) in lion. The thickest epidermis was found on the neck dorsal region in all animals. There was nonappreciable significant difference in the thickness of epidermis in various age groups and among different regions indicated that the number of cell layers constituted this layer remains constant (Table 2). Britt et al. (1985) stated that in Australian Merino sheep, the thickness of epidermis of skin of thoracolumbar region is 24.9 mm. Abbasi et al. (2008) observed that the thickness of epidermis of different regions of Lori sheep is between 8 mm and 45 mm with an average of mm. The maximum thickness of dermis ( ± mm) was recorded in adult animals followed by ± mm in young and ± mm in neonatal animals on neck dorsal region. The minimum thickness of dermis ( ± 78.40, ± and ± 49.80) was recorded in adult, young and neonatal animals respectively on thorax ventral region of skin (Table 3). Kobayashi et al. (1999) observed that in cow, the thickness of dermis of neck, abdominal and caudal regions of the skin was 11.0 ± 0.6mm, 4.8 ± 0.7mm and 5.4 ± 0.8mm respectively. The hair follicles were found to be deeper on the dorsal regions when compared to the ventral and lateral regions of neck, thorax and loin in the present study. The depth of primary hair follicle was more in young when compared to neonatal

3 animals and in adult animals, the depth was found to be maximum. In neonatal, young and adult animals, the maximum depth of ± mm, ± mm and ± mm was recorded in neck dorsal region respectively. In young and adult animals, the least depth of ± mm and ± mm was recorded on neck ventral region respectively (Table 4). The minimum depth of ± mm was found in thorax ventral region in neonatal animals and also Mir Shabir Ahmad et al., depth did not vary significantly (P>0.05) among the various regions studied in this age group. In young animals, there was no significant difference in depth of primary hair follicle between thorax lateral and thorax ventral regions. Patel et al. (1988) reported that the skin of Jersey Kankrej cross breds and Holstein Kankrej cross breds showed two fold increase in the depth of sweat gland and hair follicle from birth to 42 months of age. Table - 1 Thickness of skin (mm) at different post-natal age groups and in Tamilnadu 25 J. Veterinary & Animal Sciences 7 (1) 23-28, January - February 2011

4 Micrometrical studies on the skin... Table - 2 Thickness of epidermis (mm) at different post-natal age groups and in Same superscript (capital letters) between age groups within a row do not differ significantly (P < 0.01). Same superscript (small letters) between regions within a column do not differ significantly (P < 0.01). All values are in mean ± S.E Table - 3 Thickness of dermis (mm) at different post-natal age groups and in 26

5 Mir Shabir Ahmad et al., Table - 4 Depth of primary hair follicle (mm) at different post-natal age groups and in Same superscript (capital letters) between age groups within a row do not differ significantly (P < 0.01). Same superscript (small letters) between regions within a column do not differ significantly (P >0.05). All values are in mean ± S.E REFERENCES Abbasi, M., Gharzi, A., Karimi, H. and Khosravinia, H Effects of sex on histological characteristics of various areas of skin in an Iranian native breed of sheep. J. Ani. Vet. Adv., 7(11): Aslan, S., Kocamis, H., Gulmez, N. and Nazh, M Histological and histometrical studies on the skin of Zavot breed cattle. Indian Vet. J., 81: Bhayani, D.M., Vyas, K.N., Vyas, Y.L. and Pandya, S.P Histomorphological study on the skin of lion (Felis leo). Indian J. Vet. Anat., 7(1/2): Indian J. Anim. Sci., 74(1): Britt, A.G., Cotton, C.L., Kellett, B.H., Pitman, I.H. and Trask, J.A Structure of the epidermis of Australian Merino sheep over a 12- month period. Aust. J. Biol. Sci., 38(2): Dyce, K.M., Sack,W.O. and Wensing, C.J.G Textbook of Veterinary Anatomy, 3 rd edn., Saunders, Philadelphia, pp: Genkovski, D. and Gerchev, G Study of the skin histological structure in ewes from Staroplaninska and thoroughbred Tsigai. Biotechnol. Animal Husband., 23 (5-6): Kobayashi, A., Takehana, K., Eerdunchaolu, Bhayani, D.M., Vyas, K.N., Patel, A.M. and Vyas, Iwasa, K., Abe, M. and Yamaguchi, M. Y.L Post-natal study on the sweat Morphometric analysis of collagen: glands of Patanwadi and Marwari sheep. 27

6 a comparative study in cow and pig skins. Anat. Histol. Embryol, 28: Konig, H.E. and Liebich, H.G Veterinary Anatomy of Domestic mammals. Schatter, New York, pp: Luna, L.G. (1968). Manual of Histological Staining Methods of the Armed Forces Institute of pathology. 3 rd edn., Mc Graw-Hill Book Company, NewYork. Patel, J.M., Vyas. K.N., Vyas, Y.L. and Dave, A.D Age associated changes in skin thickness and follicle and sweat gland depth in Jersey x Kankrej and Holstein x Kankrej Micrometrical studies on the skin... F1 crossbreds. Indian Vet. J., 65: Saxena, S.K., Malik, M.R. and Parekh, H.K.B Histological character of skin in crossbred cattle. Indian J. Vet. Anat., 6(1): Sharma, D.N. and Bharadwaj, R.L Regional variations in the thickness of the skin of adult yak. Indian Vet. J., 70: Snedecor, C.W. and Cochran, W.G Statistical methods. 9 th edn., Iowa state University press, Ames, Iowa. Tripati, M., Malik, M.R. and Shrivastava, A.M Histomorphology of skin in prenatal and neonatal goats. Indian J. Anim. Sci., 66(10):