Sexual Dimorphism in Osteometric Indices of Kuri Cattle Skulls

This work investigated 30 skulls of the Kuri cattle comprising 15 males and 15 females, of three age groups, 10 young (9 months to less than 3 years), 10 middle aged (3 to 5 years) and 10 aged (greater than 5 years). The skulls were prepared using hot water maceration technique. Using Ruler, thread and divider; 59 Osteometric parameters were taken to determine sexual dimorphism, only 6 indices showed statistically significant differences between the sexes. These indices were maximum intercondylar width (MICW), right supraorbital foramen to interfrontal suture (ISRSOF), left supraorbital foramen to interfrontal suture (ISLSOF), lateral intercornual length (LICL), intertemporal line width (ITLW) and horn base circumference (HBC). The female had longer viscerocranial length (VCrL) both on the nasal and palatal aspects, but were wider in the male. The male had longer and wider neurocranium. The paracondylar process length (PCPL) was longer in the female, but the male had wider interparacondylar width (IPCW) and maximum intercondylar width (MICW) While the ISRSOF significant difference appeared only at the middle-age group at p<0.05, the ISLSOF did not differ significantly at any particular age group but only overall mean of all the three age groups (n=15) presented the difference significantly. The MICW showed significant difference (p<0.05) at two age groups; young and the middle-age. The LICL and ITLW values are highly significant (p<0.01) and the HBC value was also significant (p<0.05) all at the middle age. No significant difference was recorded between the two sexes in the aged Kuri cattle; indicating that the female tends to progressively increase in size beyond 5 years old thereby making these values insignificant from the male counterpart at old age. In conclusion, the middle-age Kuri cattle have the most sexually dimorphic osteometric landmarks in the skull with the male having higher values than the female. This data will be useful for anatomical, developmental, anthropological forensic and clinical studies, and form basis for comparison with other breeds of cattle.