Effect of age and sex on fiber and follicle characteristics of an Iranian native sheep
The mammalian hair fibers represent an interesting biological material which also is used in the textile industry. Histological structures of the fibers and follicles differ not only among different species but also among different areas and ages in an animal species. Skin samples were collected from neonatal (1-2 months), young (3-9 months), young adult (1-2 years) and old adult age groups (3 years and more). In each age group, six animals (3 each sex) were utilized. Immediately after slaughtering the animals, tissues were collected from eight regions namely belly, neck, leg, rump, flank, forearm, shoulder and hip and were fixed in 10 percent neutral buffered formalin. Histologic sections were stained with hematoxylin-eosin and special stains. It was found that the general histological features of all Bakhtiari sheep fibers used in this study were similar to many other breeds sited in literature, however there were also some differences. All hairs of the various skin regions had a medulla. All the hair follicles were surrounded by associated structures such as the sweat and sebaceous glands and arrector pili muscles and located only in papillary layer of the dermis. The most common number of the secondary hair follicles in compound hair follicles was 4. The histology of all fibers and follicles in various skin regions showed no significant differences by sex in all the age groups studied. By age increase, all the fibers and their follicles were larger and well organized in all different skin regions.