Sebaceous gland
The sebaceous glands were multilobular alveolar glands comprised of several layers of epithelial cells. These glands were associated with hair follicles in all species studied. The duct of these glands opened into the hair follicles to form a pilosebaceous canal as also reported in buffalo
(Debbarma et al., 2019), domestic animal (
Dellmann 1993), pigs
(Sumena et al., 2010), sheep
(Mamde et al., 2010 and
Mobini et al., 2012) and Goat
(Pathak et al., 2012). There was solid mass of epidermal cells in the secretory units of glands. The sebaceous glands were surrounding the hair follicle in cattle, buffalo, goat, horse, dog and pig (Fig 2,4,5,6) which was again in accordance with the results in buffalo calves
Singh et al.,1974), in adult buffalo
(Debbarma et al., 2019), in pigs
(Sumena et al., 2010), in sheep
(Mamde et al., 2010; Ahmad et al., 2010; Mobini et al., 2012 and
Razvi et al., 2013) and in goat (
Pathak and Sarma, 2013). Sebaceous glands of buffaloes were simple or compound alveolar type and were associated with hair follicle present in the reticular layers of dermis. In cattle and goat, sebaceous glands were generally present at the base of hair follicle. In dog, these sebaceous glands were arranged around compound hair follicles with one large primary follicle and eight to six secondary hair follicle along with sweat gland encapsulated with fibrous connective tissue. These results were in agreement with the same reported by
Nagaraju et al., (2012), who reported that sebaceous gland were present at the base of hair follicle whereas in dog they were present in capsule with hair follicle and sweat glands.
In the present study it was observed that the sebaceous glands of horse resembled double saccuole and composed of cuboidal cell, which were in agreement with the findings of
Obayes (2016). In pig they appeared as large, lobulated, sac like structures which is present at the base of hair follicle or they may surround hair follicle as also reported by
Sumena et al., (2012). The secretions of sebaceous glands contained lipid mixture high in cholesterol which helps the skin and hair pliable and protect them against drying and moisture (
Trautmann and Fiebiger 1967).
The distribution of sebaceous gland/mm
2 in different animals has been summarized in Table 1 and Graph 1. The maximum number of sebaceous gland/mm
2 was found in goat (1.60±0.11), followed by horse (1.27±0.16), cattle (1.25±0.15), dog (1.07±0.17), buffalo (0.98±0.16), whereas the minimum number of sebaceous gland was observed in Pig (0.44±0.06). The number of sebaceous gland/mm
2 of buffalo was significantly (p≤0.05) higher than the number of sebaceous gland/mm2 in pig. However, number of sebaceous gland/mm
2 of buffalo was significantly (p≤0.05) lower than the number of sebaceous gland/mm2 of goat. The number of sebaceous gland/mm
2 was significantly (p≤0.05) higher in Goat among all the species studied. However, the difference between the numbers of sebaceous gland/mm
2 was not significant (p≥0.05) between goat, cattle and horse. The number of sebaceous gland/mm2 was significantly (p≤0.05) minimum in pig among all.
The diameter of sebaceous gland has been summarised in Table 1 and Graph 2. The diameter of sebaceous gland in buffalo was maximum (109.83±6.14 µm), followed by dog (90±2.08 µm), cattle (88.83±2.97µm), pig (88.16±36.13 µm), horse (78.5±5.81 µm) and goat (61.16±2.42 µm). Sebaceous gland diameter of buffalo was significantly (p≤0.05) higher among all the species. Sebaceous gland diameter between cattle, horse, dog and pig varied, but it was not significant. The sebaceous gland diameter was found to be significantly (p≤0.05) lowest in goat than other species.
Sweat gland
The sweat glands were of saccular and simple coiled tubular type and most of them were associated with hair follicle as also reported earlier by Taha and Abdalla (1980),
Goswami et al., (1994) in camel,
Schummer et al., (1981) in domestic animals,
Baba et al., (1990) in sheep and
Razvi et al., (2013) in goats. Sweat glands were generally located in the deeper dermis. Glandular tubules, myoepithelium and basement membrane formed the secretory portion. Between the basement membrane and secretory cells, myoepithelial cells were present. The lumen of the ducts were narrow and lined by simple cuboidal epithelium as reported by
Hafez et al., (1955) in buffalo and cattle,
Goldsberry and Calhoun (1959) and
Govindaiah et al., (1980) in cattle,
Dowling and Nay (1962) in camel,
Lyne and Holis (1969) and
Bhayani et al., (2004) Mandage et al., (2009) in Sheep,
Razvi et al., (2013) in goat and
Debbarma et al., (2018) in buffalo. Depending upon their stage of secretory activity, the glandular epithelium was simple squamous, simple cuboidal or low columnar type as reported by
Dellmann (1993). Two types of sweat glands were seen
i.e. apocrine and merocrine. The free surface of the cells of apocrine sweat glands had cytoplasmic protrusion indicating secretory activity and merocrine sweat glands were made of tubules of cuboidal or flattened cell as also reported earlier by
Govindaiah et al., (1980) in cattle and
Debbarma et al., (2018) in buffalo.
Schumer et al., (1981) reported that the apocrine gland comprised the principal type and sweat gland in skin of domestic animals produce a viscous secretion. Large numbers of blood vessels and nerve fibers were seen around sweat gland. In the present study, the sweat gland of cattle, horse and dog were associated with hair follicles whereas in pig and goat sweat glands were not associated with hair follicle (Fig 1,2,3,4,5,6).
The number of sweat gland/mm2 different animals has been summarized in Table 2 and Graph 3 was highest in horse (3.10±0.24) followed by dog (2.25±0.15), pig (1.50±0.11), goat (1.4±0.01), cattle (0.93±0.01) and lowest in buffalo (0.76±0.05). Number of Horse sweat gland/mm
2 was significantly (p≤0.05) highest among all species. The number of sweat gland /mm2 of dog was significantly (p£0.05) higher than the number of sweat gland/mm2 of pig, goat, cattle and buffalo. The number of sweat gland/mm
2 of pig varied with goat, but it was non-significant. Similarly, the difference between the number of sweat gland number/mm
2 of buffalo and cattle was also non significant.
Diameter of sweat gland in different animals has been summarized in Table 2 and Graph 4. Maximum diameter of sweat gland was observed in buffalo (123±3.15 µm), followed by dog (75.33±2.67 µm), cattle (73.16±1.6 µm), pig (64.83±1.33 µm), horse (55.66±2.26 µm) and goat (50.33±2.85 µm).
The sweat gland diameter of buffalo was significantly (p≤0.05) highest among all the species. Sweat gland diameter of cattle was significantly (p≤0.05) higher than sweat gland diameter of pig, goat and horse. However the diameter of sweat gland of cattle varied with diameter of sweat gland of dog, but it was found to be non-significant. The sweat gland diameter of goat was significantly (p≤0.05) lowest among all. The diameter of sweat gland of goat differed with the sweat gland of horse. But it did not varied significantly.
The sweat gland diameter of pig was significantly (p≤0.05) higher than goat and horse sweat gland diameter, whereas it was less than cattle, buffalo and dog.
The number of sebaceous glands/mm
2 was maximum in Goat (1.60±0.11) and minimum in pig (0.44±0.06), whereas sebaceous gland diameter was maximum in buffalo (109.83±6.14 µm) and minimum in goat (61.16±2.42 µm) and the difference was significant (p≤0.05). The number of sweat glands/mm
2 was maximum in horse (3.10±0.24) and minimum in buffalo (0.76±0.05), sweat gland diameter was maximum in buffalo (123±3.15 µm) and minimum in goat (50.33±2.85 µm) and the difference was found to be significant (p≤0.05).
