It is a familial syndrome of Holstein-Friesian calves has been reported in aborted fetuses prematurely born, stillborn, and neonatal calves. Affected calves have anomalies in the vertebral column, including hemi vertebrae, fused and misshapen vertebrae and ribs, scoliosis, and vertebral syncostosis. Concurrent low body weight, symmetrical anthrogryposis, and cardiac anomalies have been documented in affected calves. Complex vertebral malformation is the designation for a bovine congenital syndrome caused by a mutation in the gene SLC35A3 coding an uridinediphosphate-N-acetylglucosamine transporter which is failed to transport nucleotide sugar and coenzyme which required for vertebral formation and which may be due to inbreeding and the common practice of using semen from a limited number of elite bulls and their progeny.
Source: S Raja et al., Indian Journal of Animal Reproduction: 2011; 32(1): 78-79