Spina bifida, diplomyelia, and Chiari-like malformation in an Aberdeen Angus calf.

BACKGROUND: Spina bifida and Chiari-like malformation are rare congenital anomalies resulting in severe neurological signs in calves. The cause is unclear, but genetic and environmental factors are thought to play a role. CASE PRESENTATION: A one-day-old, female, Aberdeen Angus calf was referred to the Clinic for Cattle, University of Veterinary Medicine, Hannover, Germany, because of inability to stand. The calf had a circular hairless area located over the caudal part of the sacrum and showed paraparesis, reduced spinal reflex responses in the hind limbs, ventral strabismus, and exophthalmos. Intracranial and hind limb lower motor lesions were suspected. Radiography and magnetic resonance imaging showed a congenital absence of the sacral vertebral arch from sacral vertebra (S) 3 to S5, a hydro-meningomyelocele, deformation of the four brain ventricles, and severe herniation of the cerebellum through the foramen magnum. The calf was humanely euthanised, and a postmortem examination showed severe congestion and herniation of the cerebellar vermis. The vertebral arches of S3, 4, and 5 were incompletely developed to absent, and the cervical spinal cord had dilatation of the central canal (hydromyelia) and bilateral cavitation (syringomyelia). Additional central canals with a smaller diameter (diplomyelia) were also present. Whole genome sequencing revealed GRM7 as a possible candidate gene associated with cerebellar displacement and Chiari-like malformation. CONCLUSIONS: This case report highlights the importance of including congenital malformations in the differential diagnosis of calves with neurological signs. Such abnormalities are often challenging to diagnose and require imaging procedures. Further research is needed to determine the genetic basis of these malformations.