Scanning electron microscopic characterization of hair cuticles and medullary patterns of some specialized hairs of the Philippine carabao (Bubalus bubalis, Linnaeus)

Specialized hairs and long hairs of 30 adult male and female Philippine carabaos were examined for surface morphology by means of scanning electron microscope and medulla pattern with the use of light microscope. Sites of collection included the eyelids, above the eyelids, muzzle, concave surface of the external ear, and the switch of the tail. The study showed that hairs from the ears, eyelids, and tails of both sexes exhibited an imbricate crenate cuticular pattern while hairs from the muzzle and the region above the upper eyelid did not exhibit any scales. Between sexes, the difference observed was the more stacked cuticular scales in the male. The scales on the hair of the external ear and eyelid of female and tail of male were transversely oriented; scales of hairs from ears of male and tail of female were irregularly oriented; and the hairs from the upper eyelids of male were obliquely oriented. The dorsal margin of all the scales observed was serrated. The scales were small and were moderately to highly stacked. Hairs from the concave surface of the external ears showed absent, fragmented and continuous medullary pattern. Highly pigmented hairs from the ears of male animals showed fragmented to absent medulla. In unpigmented hairs, continuous medulla could be observed. Continuous medullary patterns was exhibited both in pigmented and unpigmented ear hair of the female. Long tail hairs of male animals showed narrow continuous pattern and a narrow segmented pattern in the eyelid. A compound elongated pattern was seen on the hairs of the muzzle of male animals. No medulla was observed in other regions especially in the female. This could be due to the heavy pigmentation of the cortex that the medulla cannot be seen or the medulla was really absent in these samples. Medullary pattern cannot be associated with a particular cuticular pattern. As shown in this study, the hairs from different regions examined had imbricate crenate cuticular pattern. However, more than one medullary pattern was observed in a given body region. The hairs of the male and female cannot be differentiated from one another because of the similarity in morphology. The present study showed that scanning electron microscopic characterization of the hair cuticles and light microscopic description of medullary patterns could be used in species identification. However, application of these methods becomes limited in cases of absence of cuticles due to traumatic injuries, and when there is a thick and highly pigmented cortex. In such cases, cuticular and medullary findings should be supplemented with gross observation (size of hair, color of hair, and cross section of medulla) and if available, DNA analysis