THE CORRECTION FACTOR OF HAIR DENSITY IN THE SKIN OF BUFFALO

The hair density of the back region in water buffalo was calculated by counting the number of hair follicles in the horizontal sections prepared by conventional paraffin embedding method and stained with hematoxylin and eosin . The calculated hair density was 3.53 hair follicle/mm of the buffalo skin. All the hair follicles were of primary type and distributed randomly. The skin samples showed different variable shrinkage percentage during routine histological technique. The shrinkage percentage of surface area of the stained sections was found to be 21 % of the original value. Thus the correction factor of the hair density was calculated to be 0.79, this leads to conclusion that the actual hair density of the back region of the skin of living buffalo is 2.78 hair follicle/mm only . سوماجلا دلجل ةيرعشلا ةفاثكلل ححصملا لماعلا ميحرلا دبع نسح ديؤم و سايلا يتم ملاسلا دبع و دمحا ناطلس ةھيزن او حيرشتلا عرف لصوملا ةعماج ،يرطيبلا بطلا ةيلك ،ةنجلااو ةجسنلا ، قارعلا ،لصوملا ةصلاخلا سوماجلا دلج يف رھظلا ةقطنمل ةيرعشلا ةفاثكلا تبسح رھنلا تابيرج دادعتب ي عطاقملا نم رعشلا ةغبصب ةغوبصملاو نيفارابلاب ءاجسلاا ةقيرطب ةرضحملا ةيقفلاا لا غلب ثيح نيسويلااو نيلسكوتاميھ ٥٣ ‚ ٣ رج رعش ةبي / ملم ٢ تناكو سوماجلا دلج نم عيزوتلا ةيئاوشعو يئادتبلاا عونلا نم رعشلا تابيرج . تاريرمتلا نم ةوطخ لك دعب شامكنلاا نم ةتوافتم تاجرد دلجلا تانيع ترھظأ ةيدايتعلاا ةيجيسنلا .. ةغوبصملا ةيجيسنلا عطاقملا يف يئاھنلا شامكنلاا ةبسن تغلبو ٢١ % قف كلذ ىلا ادانتساو ً سوماجلا يف رھظلا ةقطنمل ةيرعشلا ةفاثكلل ححصملا لماعلا غلب د ٧٩ ‚ ٠ ةيرعشلا ةفاثكلا نأ كلذ نم جتنتسيو ةيقيقحلا يھ يحلا سوماجلا يف رھظلا دلجل ٧٨ ‚ ٢ رعش ةبيرج / ملم ٢ طقف . INTRODUCTION The hair density is usually calculated by examining the number of hair follicles in a definit surface area of the stained horizontal sections of the paraffin embedded skin samples (1, 2, and 3). Iraqi Journal of Veterinary Sciences, Vol. 20, No.2, 2006 (101-106) 102 The different chemical substances used in routine histological processing i.e.: fixation, dehydration, clearing and wax embedding affect the surface area of the stained samples , which is decreased if compared to fresh samples (4, 5) this decrease in the surface area reflects a higher hair density in comparison to the fresh skin. Therefore, the false reading of the hair density of the stained skin samples should be corrected to these normally existing in the original fresh skin by applying a correction factor of the hair density. The correction factor of the hair density in the skin of goats , sheep , cattle and camel has been measured by several authors ( 6, 7, 8, 9, 10), but the correction factor of the hair density in the skin of local water buffaloes received no attention. The goal of this work is to find out the correction factor of the hair density in this animal. MATERIALS AND METHODS Samples of skin from the back region of 8 male buffaloes of 1-2 years old were collected by a punching tool of 10 mm diameter. The samples were fixed in a neutral buffered formalin for 24 hours and then immersed in 4% phenol for 24 hours to soften the keratinized material of the skin (10, 11). The samples were dehydrated by ascending grades of ethyl alcohol, cleared with xylene and infiltrated with paraffin wax of 56C melting point. Horizontal sections of 5-6 μm thick were cut at sebaceous glands level and stained with routine hematoxylin & eosin and trichrome stains (5). Hair density were calculated by counting the number of hair follicles in a known surface area of the microscopic field, which is confirmed by the counting device of the visopan microscope (Fig.1). Figure 1: Explaining the calculation of surface area of the section by using a visopan device. Iraqi Journal of Veterinary Sciences, Vol. 20, No.2, 2006 (101-106) 103 The correction factor is obtained by following the formula a1/ a2 applied by Carter and Dolling 1954, where a1: represents the surface area of the stained section , while a2 : represents the surface area of the fresh sample of skin (7). RESULTS All hair follicles in the dermis of back skin in native water buffaloes were found to be of primary type and distributed evenly (Figure 2). Figure 2: Horizontal section of buffalo skin at sebaceous gland level. Note the even distribution of primary hair follicles . Trichrome stain X 190 . The alterations in the surface area of the skin samples following fixation, phenol treatment, dehydration, clearing, paraffin embedding & sectioning and staining were recorded in Table 1. Table 1 : Differences in surface area and shrinkage percentage during routine histological processings of buffalo skin .