Craniometric indices of the skull of adult Nigerian indigenous Pigs (Sus scrofa)

Abstract

The structure of the skull is a unique feature of each animal that allows for individual, breed and species differentiation. Craniometric analyses involve the determination of skull dimensions between anatomically-defined landmarks and such dimensions are useful in assessing the contributions of genetic and environmental components to an individual's development. The present study was designed to investigate 35 craniometric indices of 24 adult Nigerian indigenous pigs (NIP) skulls (10 males and 14 females). The data obtained were analysed using the Student’s t-test (p≤0.05) and Pearson Correlation (p≤ 0.05). The study revealed that 42.8% of the measured parameters were higher in males. The skull length was 23.02±0.35cm and 22.02±0.25cm, skull width was 11.01±0.18cm and 11.01±0.17cm, whole skull index was 63.26±1.60 and 65.07±0.48, and foramen magnum index was 104.15±2.70cm and 98.03±1.70cm, for males and females respectively. These values were however not statistically significant (p>0.05) between both sexes. The skull of the NIP was categorised as dolichocephalic, according to its cephalic index (63.26±1.60). The orbit of the NIP appeared slightly oval in shape, having a relatively higher vertical diameter than the horizontal diameter. The mandibular length was statistically longer in male skulls (19.02±0.41cm) when compared to female skulls (18.04±0.26cm). The skull length showed a significant positive association with the skull width and the nasal bone length, while the foramen magnum width showed a significant positive association with the foramen magnum index. Data generated provide important information on the skull of NIP which can be used for comparative anatomical, developmental, forensic, and clinical studies.