Examining neurocranial development in Iraqi indigenous sheep (Ovis aries): An osteomorphometric study

The skull is a collection of symmetrical and asymmetrical bones that protect the brain and house the sensory organs. The skull's shape defines the head's structure, which is closely linked to various physical and phenotypic characteristics usually used to classify and typify diverse strains of animals, their genomic profiles, and their association with close atmosphere. This work aims to define the osteomorphometrical parameters of the neurocranium, skull base, and cranial cavity capacity (CCC) using 48 Iraqi domestic sheep fetuses at 50-155 days of gestation, measured using electronic Vernier and measurement tape. The fetuses’ skulls were prepared by maceration using NaOH. CCC was obtained by filling it with mustard seeds through the foramen magnum. Thirty-two osteomorphometrical parameters were measured within the dorsal, lateral, and ventral surfaces. The work showed significant differences in skull length and width at 7-15 weeks of pregnancy, and the correlation between the cranial cavity capacity was very strong and positive with all variables. While the width of the foramen magnum increases significantly with progressive the pregnancy. The foramen magnum index showed a downward trend from the period 7-11 weeks, then an upward trend from the period 12-16 weeks, then a downward trend again from the period 17-19 weeks, where it appeared almost oval. A weak correlation between the orbital index and the total length variable, and the orbital cavity took an almost circular shape. Skull measurements can used in breeding programs to improve desired traits, achieve specific production goals, and help identify animals with superior genetic traits.