SUMMARY: The morphology of filiform papilla root in the tongue of Chinese yellow cattle were studied by scanning electron microscopy, and several geometric models were established to analyze the possible effects of such structures on lingual mechanical functions. Conical and tongue-like filiform papillae were detected in different locations on the lingual surface, along with six types of root structures. A lingual groove surrounded the papillae in five of these structures. To date, such grooves have not been discussed in studies on bovine lingual morphology, and those distributed on the dorsal surface of the lingual apex can limit the motion ranges of filiform papillae. Two secondary papillae emerged from a groove on the dorsal surface of the lingual apex’s caudal half; these papillae can protect a filiform papilla root from damage. The grooves and the flat orientation of such papillae on the dorsal surface of the lingual body can reduce energy expenditure during forage transportation. A lingual rib that can strengthen the filiform papilla root emerged from a groove on the dorsal surface of the rostral half of the lingual body. On the dorsal surface of the lingual body’s caudal half, all filiform papillae emerged from a groove to form low lingual walls that can protect the roots from being crushed by forage. High lingual walls were generated on the lateral surface of the lingual apex; these walls enable filiform papillae to adapt to harsh food environments effectively. The root structures on the lingual body’s lateral surface were adequately simple and did not exhibit lingual grooves; thus, hydraulic resistance may decrease during mastication. Diverse root structures can optimize the lingual mechanical functions and improve self-protection capability in combination with the appearance and distributions of these papillae. All the aforementioned features may be the result of environmental adaption and cattle evolution.
KEY WORDS: Morphology; Root structure; Filiform papillae; Mechanical function; Tongue.
