author(s)
S Senthilkumar, R Gnanadevi, TA Kannan, CS Arunaman and Geetha Ramesh

abstract
Microscopic observations of guard hairs collected from three different regions viz., inter scapular, lumbar and croup regions of the different domestic animals viz., cattle, buffalo, sheep, goat, horse and dog was carried out. Hair is an epidermal outgrowth which was made up of an outer cuticle, middle cortex and inner medulla in all the species. The cortex was non-cellular and the medulla was cellular made up of cornified cells in all species except dog. In cattle, buffalo and goat the scaling pattern was imbricate with no protrusions from hair shaft. Whereas, in dog, the scales were not prominent. 50 per cent of total diameter of the hair was made up of medulla. Medullary index of domestic animal hair ranged from 0.30 to 0.75. Within each species, the mean diameter of shaft portion of hair varied in different regions. Among the domestic animals, horse had the least medullary index of 0.30 and sheep and goat had the maximum medullary index of 0.75.