Basrah Journal of Veterinary Research,Vol.17, No.3,2018
Proceeding of 6th International Scientific Conference,College of Veterinary Medicine
University of Basrah,Iraq
652
A COMPARATIVE TOPOGRAPHICAL AND HISTOLOGICAL STUDY OF HAIR
AND HAIR FOLLICLES OF SHAMI GOAT AND BLACK GOATS IN THE MOSUL
PROVINCE.
A. N. Abduljawaad, Alhaaik A.G. and M. H. Abdulraheem
Department of Anatomy and Histology College Veterinary Medicine/University of Mosul, Iraq
Key word: Skin, Hair follicles, Shami goat.
Corresponding Author: alhaaik_ag@yahoo.com
ABSTRACT
This study was conducted to prepare a database about hair follicles of Shami goat skin and to compare it
with that of Black goat. To achieve this goal, a comparative topographic histological study of 10 areas of
Shami goat skin and similar areas of the Black goat skin was performed. Samples of 10 male animals (5)
Shami goats and (5) Black goats used in this study were clinically healthy, 1-2 years old . Hair follicles in
most studied areas were of the composite type of primary and secondary hair follicles in both animals except
for the ventral surface area of the tail where primary follicles were present only. The length of hair follicles
in Black goats of all studied areas was longer than that of Shami goats. However, the depth of hair follicles
in skin of Shami goats was significantly lower than that of Black goats, indicating that the angle of hair
follicles in Shami goats is greater than those of Black goats. The follicles in Black goats were larger than
those of Shami goats, indicating that the Shami goats hair was softer than that of Black goats. Shami goats
hair had softness more than that of Black goat' hair. This softness is attributed to the increases the ratio of
secondary hair follicles to primary hair follicles in Shami goats in most studied areas compared with those in
Black goats. The follicular arrangement was studied in both species, however, the triangular arrangement of
the follicles was predominant in both animals except for the ventral area of the tail, where the trio follicular
arrangement appeared only in the Shami goats and did not appear in the Black goats where they spread
uniformly and not in groups.
INTRODUCTION
The skin is the organ that surrounds the body, protects the organs under it from mechanical and
physiological external effects (1). As well as it helps in regulation of body temperature, excretes sweat and
sebum, and reflects the general body condition ( 2). The skin of goat also is a source of hair, which is used in
different textiles and depends on the quality of the hair produced, and this is of economic importance (3).
There have been many studies dealing with different aspects of different animal skins. The study conducted
by (4) who investigate the histomrphometrical features of skin of one-humped camel , in the same manner
Basrah Journal of Veterinary Research,Vol.17, No.3,2018
Proceeding of 6th International Scientific Conference,College of Veterinary Medicine
University of Basrah,Iraq
653
(5,6) examined the topography and morphometry of basic components in different areas of the skin of Black
goats.
In spite of presence of many studies about the skin of different farm animals in Iraq (7, 8, 9, 10 and 11) but
there was no standard histological studies of the hair and follicles of the Shami goat skin. Most of the
available Shami goat research is related to milk production and fertility (12, 13, and 14). Therefore, this
research aimed to provide a basic knowledge base for hair and hair follicles, including a histological and
morphometrical study of different areas of Shami goat skin compared to corresponding areas in Black goats.
MATERIALS AND METHODS
Skins of 10 healthy male animals (5) Shami goats and (5) Black goats aged between (, 1-2 years) were used
in this study, samples were taken immediately after slaughter, and were collected in the autumn. Ten
different areas of each animal's skin were selected for study (frontal area, the medial surface of forelimb,
The lateral surface of the forelimb, the anterior abdomen region, the anterior back, the middle back region,
the medial surface of the hind limb, the lateral surface of the hind limb, the ventral surface of the tail and the
dorsal surface of the tail).
Neutral buffered formalin solution was used to fix the samples for at least 72 hours, followed by routine
histological processing methods , using increasing concentrations of ethyl alcohol starting from (80%, 90%,
100%) for dehydration and chloroform was used as clearing agent.
The samples were passed with melted paraffin wax with a melting point (58-60 °C). The samples of each
region were divided into two groups, the first group was oriented horizontally and the second set vertically
within the wax blocks. The wax blocks were cut by a rotary microtome to get 5-7 μm histological sections .
Hematoxylin and eosin stain was used for histological study and microscopic measurements (15), while the
Masson's Trichrome stain was used for differentiation between muscle fibers and connective tissue fibers
(16). The histological sections were photographed as well as micromorphometric parameters were measured
using the color USB 2.0 digital image camera (Scope Image 9.0- China) which was provided with image
processing software. The software of camera was calibrated to all lenses of Microscope-Olympus-CX31 by
aid of 0.01mm stage micrometer (ESM-11 / Japan).
The micromorphometric measurements were done for all vertical and horizontal sections of selected areas of
skin in both species and the parameters included the followings: length and depth of primary follicles, length
of secondary follicles, diameter of each of primary and secondary follicles.
Basrah Journal of Veterinary Research,Vol.17, No.3,2018
Proceeding of 6th International Scientific Conference,College of Veterinary Medicine
University of Basrah,Iraq
654
Statistical analysis:
Computer package (Sigma plot V12.0 / SYSTAT software) was used to conduct the histomorphometrical
analysis. Data were presented as means ± SE (standard error) and were analyzed using t- test with
significant level set on P <0.05 .
RESULTS
The study showed that the hair of both Shami goats and Black goats consists of two types of hair. The
primary coarse hair composed of three layers, from the outside to the inside cuticle, the cortex, and the
medulla (Fig. 1) and extends deep in the dermis (Fig. 3), accompanied by the sweat glands, sebaceous
glands, arrector pilli muscle (Fig. 2). The secondary hair composed of two layers, the cuticle and cortex
without the medulla (Fig. 3) which is located more superficially than the primary one, and not accompanied
by sweat glands and arrector pilli muscle. It is accompanied by some sebaceous glands.
The hair follicles are structures that originated from the skin epidermis and extend deep in the dermis. The
hair follicle consists of an inner layer and an outer layer that encapsulates the hair root, the inner layer called
the internal root sheath, it can be distinguished in the lower two thirds of the hair follicle before the opening
of the sebaceous gland.
The internal root sheath consists of three concentric layers, from the outside to the inside which are Henle's
layer, or the so-called pale epithelial layer, consisting of a single row of keratinized columnar cells its
longitudinal axis extend toward the length of the hair follicle. These cells appear cuboidal in the cross
section which facing the inner surface of the outer sheath, followed by a Huxley's layer or a granular
epithelial layer, this layer consists of one to three rows of irregular keratinized cells and contains an
abundance of the trichohyaline granules and then followed by cuticle's layer of the internal root sheath
which consists of keratinized and interstitial cells like cuticle of hair, except that its free edges are directed
in the opposite direction. The outer sheath of the root consists from several layers of cells similar to the basal
cells which represents the continuity of the basal and spinal layers of the epidermis but without a corneal
layer. The thickness of the outer sheath decreases towards the hair follicle, where the follicle cells
responsible for the formation of hair itself.
Our study showed that there was a clear difference between the lengths of primary hair follicles in Shami
goats and had the longest hair follicle in the middle back region (Fig. 3). The average length was 2182.35
μm while the shortest hair length was in the ventral surface of the tail (Fig.4) where it reached 1065.56 μm
from (Fig. 13) the results showed that the primary hair follicles in the dorsal areas and the lateral surfaces of
the limbs were longer than those in the ventral regions and the medial surfaces of the limbs of both Shami
Basrah Journal of Veterinary Research,Vol.17, No.3,2018
Proceeding of 6th International Scientific Conference,College of Veterinary Medicine
University of Basrah,Iraq
655
and Black goats. However, the mean length of follicles in all studied areas in Black goats was higher than
the corresponding areas in Shami goats (Fig. 13)
It is worth mentioning that the depth of hair follicles in Shami goat was significantly less than the depth of
follicles in all studied areas of Black goat, indicating that the angle of hair follicles in Shami goat was larger
than in Black goats, so hair and hair follicle is relatively parallel to the skin surface in Shami goat than them
in Black goats (Fig. 15).
The primary follicles of Shami and Black goats differed in according to different areas (Table 1). Primary
hair follicles of Shami goat ranged from 92.95 to 171.16 μm while primary hair follicles in Black goats
ranged between 94.29-182.7 μm. This indicates that diameters of hair originated from follicles in Shami
goats were lower than those in Black goats. The results showed that the primary follicles in the dorsal areas
and the lateral surfaces of the forelimbs and hind limbs were larger than those in the ventral areas and
medial surfaces of the front and back limbs (Table 1).
The study showed that the mean length and diameter of secondary follicles in Black goats were higher than
in Shami goats for all studied areas (Table 1), (Fig. 14) therefore the primary and secondary hair follicles in
Black goats were larger than in the Shami goats, and this indicates that the hair of the Shami goats is more
soft than that of the Black goats.
The study showed that hair follicles in most studied areas were from complex type and consisting of a single
primary follicle with a number of secondary follicles except the area of the ventral surface of the tail was
simple because of the lack of secondary follicles in this area for both species and this result was not
mentioned in Any of the previous research (Fig. 5). Secondary follicles were opened to primary follicle at
the site of opening of the sebaceous glands (Fig. 6), to be later the compound follicle.
Arrangements of hair follicles
The study showed that hair follicles in both species were not randomly distributed in the skin, but rather in
the form of solitary, doublet and trio groups (Fig. 7, 8). Some quaternary and quintile groups may exist (Fig.
9, 10) but the trio arranged was common in all studied areas (table 2). Whatever these follicles are organized
linearly in most regions (Fig. 7).
The solitary and doublet arrangement is predominant in Black goats skin compared to Shami goats for most
regions, while the trio arrangement may predominate slightly in Shami goats compared to Black goats and in
most of the studied areas. The quaternary arrangement was found in most areas of the Shami goat skin, this
arrangement was not observed in the skin of the anterior surface of the front and back of the Black goat skin.
The quintile arrangement appeared in the frontal area, the dorsal areas and the lateral surfaces of the front
and back limbs of both animals (Table 2).
Basrah Journal of Veterinary Research,Vol.17, No.3,2018
Proceeding of 6th International Scientific Conference,College of Veterinary Medicine
University of Basrah,Iraq
656
Our study showed a significant difference in follicular regulation in the area of the ventral surface of the tail
between the two animals. The trio and doublet follicular arrangement, as well as the solitary arrangement of
the Shami goats, were shown in the Black goats and for the same region only in the solitary arrangement
(Fig. 11, 12) (tab.2).
DISCUSSION
The results of our study revealed two types of hair in the skin of both Shami goats and local Black goat, the
coarse hair produced by primary hair follicles and consists of cuticle, cortex and medulla and the follicle of
this hair extends deeply in the dermis and may reach the subcutaneous layer (18) accompanied by sebaceous
glands and sweat glands and the arrector pili muscle of the hair.
Whereas the soft hair produced by secondary hair follicles, which consists of cuticle and cortex and does not
contain medulla. These follicles do not accompanied by sweat glands or the muscle of the hair follicle. They
are accompanied by some sebaceous glands. This is consistent with what is mentioned in (19) in pets and
(20) in Arabian camel. The results of the study showed a difference in the lengths of hair follicles according
to the different regions of the skin, as confirmed by (4) in one – humped camel. Generally, the length of
primary and secondary hair follicles in the front and back areas and the lateral surface of the limbs were
greater than the abdominal and medial surfaces of the limbs. This is consistent with the reference to (5) in
Black goats. This may be due to a positive relationship between the thickness of the dermis and the length of
the hair follicles. Comparative results showed that the mean length of primary and secondary follicles in all
studied areas of Black goats was longer than the corresponding areas in Shami goats. No research was
available to justify this finding and may be attributed to genetic causes.
It was also found that the depth of primary hair follicles in Shami goats was significantly lower than the
depth of the follicles in the Black goats and if we take into consideration the absence of significant
difference in the length of hair follicles in both animals, this indicates that the angle of Orientation of
primary hair follicles in Shami goat higher than in Black goats. This leads to the fact that the hair of the
Shami goats is relatively parallel to the surface of the skin compared to the Black goats, which may give a
smooth appearance to the hair of the Shami goats.
The diameters of primary and secondary follicles of Shami goats and Black goats varied according to
different areas of study and this is similar to that in one-humped camel (4). Our study showed that the hair
follicles emitted from primary and secondary follicles of Shami goats are lower than in Black goats. This
gives the hair of the Shami goats a much smoother and more beautiful appearance than the Black goats. Hair
follicles in most studied areas in both species were composed of complex follicles consisting of one primary
follicle and a number of secondary follicles.
Basrah Journal of Veterinary Research,Vol.17, No.3,2018
Proceeding of 6th International Scientific Conference,College of Veterinary Medicine
University of Basrah,Iraq
657
Secondary follicles are usually opened on primary hair follicles. In some cases, small numbers of secondary
follicles are opened directly on the surface near the primary follicle. This is consistent with what was
mentioned by (6) in goat. The area of the ventral surface of the tail in both species was characterized by the
presence of simple primary follicles due to the absence of secondary follicles in the ventral surface of the
tail. The phenomenon that indicates that these follicles are primary follicles which is accompanied by sweat
gland duct.
The results of the study showed that the compound hair follicles in both animals and for most areas of the
study were not distributed randomly, but in groups and each group consists of primary and secondary
follicles, which was mentioned by (20) in Arabic camels. Primary follicles are organized in a linear or semioblique
pattern. The central primary follicle has been shown to be slightly larger than the primary peripheral
follicles, which is confirmed by (2) in animals with complex follicles.
Our study showed that the trio arrangement of the follicles was predominant in both animals. This
arrangement was described by (21) in Bengali goats and (22) in local Awassi sheep. However, it was
slightly predominant in Shami goats rather than in Black goats, as well as, doublet and quaternary groups
were also found at a lower rate, and only a few quintile groups were observed and in both species.
There was also an obvious difference in the follicular arrangement in the area of the ventral surface of the
tail between the Shami goats and the Black goats. The arrangement of the follicular groups appeared in the
Shami goats only, whereas the primary follicles in the Black goats of the same region were spread uniformly
and not in groups, it has been attributed to genetic causes.
Basrah Journal of Veterinary Research,Vol.17, No.3,2018
Proceeding of 6th International Scientific Conference,College of Veterinary Medicine
University of Basrah,Iraq
658
Fig. (1). A horizontal histological section of the skin of
the ventral surface area of the tail in the Shami goats. Note
the primary hair layers of, medulla( M), cortex ( c ),
cuticle (CU) , internal root sheath (IRSH) , Henle layer
(HN) , Huxley layer (HX) , external root sheath (ERSH) ,
and dermis sheath( DRSH) . (Masson's Trichrome stain,
650X).
Fig (2). A horizontal histological section of the skin of
the anterior back area in the Shami goats. Notice the
cross section of the secondary hair. Cortex( C )and
internal sheath IRSH with Henle (HN )and Huxley
(HX,) external root sheath (ERSH) , and dermis
sheath( DRSH). (Masson's Trichrome stain, 650X).
Fig (3). Vertical histological section of the skin of
the middle back area in the Shami goat. Note the
length of primary hair follicle PHF and its
extension in the dermis and the less extension of
secondary hair follicles SHF with the presence of
secretory units of the sweat gland SWGU. ( H&E
stain, 370X).
Fig (4). Vertical histological section of the skin of
the ventral surface area of the tail in Shami goats.
Note the short length of primary hair follicles and
the lack of extension in the dermis with the
presence of the units of sweat gland SWGU and
sebaceous glands SBG associated with primary
follicles. (H&E stain, 370X).
Basrah Journal of Veterinary Research,Vol.17, No.3,2018
Proceeding of 6th International Scientific Conference,College of Veterinary Medicine
University of Basrah,Iraq
659
Fig (5). A horizontal histological section of the skin
of the ventral surface area of the tail in the Shami
goats. Note the absence of secondary follicles and
the accompaniment of a sweat gland duct SWGD
for each primary hair follicle PHF. (Masson's
Trichrome stain, 165X).
Fig . (6). Horizontal histological section of the skin
of the lateral surface area of the hind limb in local
black goats. Note the opening of the secondary
hair follicle SHF on the primary follicle PHR and
note the presence of the SBG associated with the
primary hair follicle. (H&E stain, 370X).
Fig (7). Horizontal histological section of the
skin of the middle back area in the Shami goats.
Note the trio arrangement of the follicles, the
linear pattern of the primary follicles, the
secondary follicles SHF, sweat gland duct SWD
and arrector pili muscle APM (Masson's
Trichrome stain, 90X).
Fig (8). A horizontal section of the skin of the
anterior back area in the Shami goats. Note the
solitary arrangement, the existence of the sweat
gland duct SWD, the sebaceous glands SG and
the secondary hair follicle SHF, the arrector pili
muscle APM. (Masson's Trichrome stain, 115X).
Basrah Journal of Veterinary Research,Vol.17, No.3,2018
Proceeding of 6th International Scientific Conference,College of Veterinary Medicine
University of Basrah,Iraq
660
Fig (9). A horizontal section of the skin of the
anterior back area in the Shami goats. Note the
quaternary arrangement with the presence of
sebaceous glands SBG associated with primary
follicles and secondary hair follicles (SHF).
(H&E stain, 90X).
Fig . (10). A horizontal section of the skin of the
dorsal surface of the tail in the Shami goat at the
mid-third level of the dermis. Note the quintile
arrangement of primary follicles and note
secondary follicle occupy the Ectal side while
the sweat gland duct and the sebaceous gland
and the arrector pili muscle occupy the opposite
side Ental side. (Masson's Trichrome stain,
90X).
Fig (11). A horizontal section of the skin of the
ventral surface area of the tail in the Shami
goats. Note the regularity of primary follicles in
groups as observed by the absence of secondary
follicles. (H&E stain, 90X).
Fig (12). A horizontal section of the skin of the
ventral surface area of the tail in the black goat.
Note the mono arrangement of primary hair
follicles without secondary follicles. (H&Estain,
90X).
Basrah Journal of Veterinary Research,Vol.17, No.3,2018
Proceeding of 6th International Scientific Conference,College of Veterinary Medicine
University of Basrah,Iraq
0
500
1000
1500
2000
2500
frontal
area
medial
surface
of
forelimb
lateral
surface
of
forelimb
0
200
400
600
800
1000
1200
1400
frontal
region
medial
surface
of
forelimb
Fig. (14) Show the lengths of secondary hair follicles in depth of dermis for all studied skin
regions of Shami goat and Black goat / μm
Fig. (13) show the lengths of primary hair follicles in depth of dermis for all studied skin
regions of Shami goat and Black
661
medial
surface
of hinde
limb
lateral
surface
of hinde
limb abdomen
anterior
back
middle
back
ventral
surface
of tail
anatomical regions of samples
shami goat black goat
lateral
surface
of
forelimb
medial
surface
of hind
limb
lateral
surface
of hind
limb
abdomen
region
anterior
back
middle
back
ventral
surface
anatomical regions of samples
Shami goat Black goat
lack lack goat / μm
dorsal
surface
of tail
of tail
dorsal
surface
of tail
Basement
membrane
Basement
membrane
Basrah Journal of Veterinary Research,Vol.17, No.3,2018
Proceeding of 6th International Scientific Conference,College of Veterinary Medicine
University of Basrah,Iraq
662
0
200
400
600
800
1000
1200
1400
1600
1800
frontal
area
medial
surface
of
hindlimb
lateral
surace of
forelimb
medial
surface
of
hindlimb
lateral
surace of
hindlimb
anterior
abdomen
anterior
back
middle
back
ventral
surface
of tail
dorsal
surface
of tail
depth in dermis ا
anatomical region of samples
shami goat black goat
basement
membrane
Fig. (15) Show the depth of primary hair follicle inside the dermis in all studies skin
regions in Shami goat and Black goat/ μm.
Basrah Journal of Veterinary Research,Vol.17, No.3,2018
Proceeding of 6th International Scientific Conference,College of Veterinary Medicine
University of Basrah,Iraq
663
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