Congenital anophthalmia with caudal vertebral anomalies in Japanese Brown cattle.

Anophthalmia and caudal vertebral anomalies such as taillessness or wry tail were morphologically examined in ten Japanese Brown calves obtained in Kumamoto Prefecture. The anomalous calves lacked eyeball bilaterally or unilaterally but had small-sized eyelids and narrow palpebral fissures. A small cystic, solid or spot-like remnant of eyeball (REB) was buried in the mixture of vestigial extraocular muscles, lacrimal gland and adipose tissue of the orbit. The REB was composed of irregularly arranged elements of ocular wall such as sclera, choroid and retina. The retina was often dysplastic and connected to the hypoplastic optic nerve. These morphological changes might represent the defective processes after the formation of the optic vesicle or cup. Therefore, this eye defect may be defined as degenerative anophthalmia. The defects of the vertebral body such as wedge vertebra, hemivertebra, and sagittal cleft vertebra seen in the lumbar, sacral, and coccygial regions and the meandering of the axial line of abnormal vertebrae may suggest the failure of notochord formation in the early fetal period. From the embryological point of view, it seemed possible that the calves were exposed to teratogen at the critical time of optic organogenesis and notochordal formation. The cause of anomalies could not be determined in this study.