Abstract
Background: Indigenous sheep breeds play an important role in rural livelihoods by providing meat, hides, and manure. Detailed cranial anatomical characterization is therefore essential for improved breed utilization, clinical diagnosis, and surgical management.
Aim: This study comparatively assessed the gross cranial morphology and clinically relevant anatomical landmarks of Uda and Yankasa sheep breeds.
Methods: A total of ten (10) heads, comprising five (5) Uda and five (5) Yankasa rams aged 12–18 months, were sourced from Bauchi Metropolis, Nigeria. The samples were processed in the Gross Anatomy Laboratory of the University of Maiduguri using hot water maceration and soft-tissue removal techniques. Morphological evaluation focused on facial tuberosities, infraorbital, supraorbital, and mental foramina, frontal bone depressions, and choanal margins. In addition, six (6) craniofacial indices were calculated to assess morphometric differences between the breeds.
Results: The findings revealed both similarities and marked interbreed variations. Uda skulls exhibited greater positional variability and more pronounced tuberosity development than Yankasa. The infraorbital foramen showed relatively consistent positioning in Yankasa but varied widely in Uda. Frontal bone depressions were present in both breeds but were more frequent and deeper in Uda. Choanal margins differed between breeds, appearing mainly U-shaped in Yankasa and V-shaped in Uda. There is no statistically significant difference in the craniofacial indices among the two breeds, but the skull index shows a slight difference between Yankasa (42.94 ± 2.29) and Uda (41.57 ± 2.42). The orbital index was higher in Uda, while other indices showed minor, non-significant variations.
Conclusion: This study provides baseline information that enhance understanding of breed-specific anatomy, with important implications for taxonomy, and veterinary clinical practice, particularly regional anesthesia and head surgeries.

Key words: Sheep skull, Uda, Yankasa, Craniomorphometry, Craniofacial indices.