Complex vertebral malformation in Holstein cows in Japan and its inheritance to crossbred F1 generation

Complex vertebral malformation (CVM) is an autosomal recessive inherited defect in the Holstein breed. It causes intra-uterine mortality leading to repeat breeding and involuntary culling of cows. This study was carried out to show the prevalence of CVM carriers among Holstein cows in five dairy farms in Hiroshima Prefecture, South Western Japan and whether the defect could be inherited to crossbred F1 generation, when Japanese Black semen was used to inseminate a Holstein cow. Two hundreds Holstein cows were used in the study. Blood samples were collected from all cows in a heparinized tubes and genomic DNA was extracted with a commercial kit. Apart of the bovine solute carrier family 35 member 3 (SLC35A3) gene around the suspected mutation (G to T) was amplified with an allele specific polymerase chain reaction (AS-PCR). For DNA sequencing, PCR products of 522 bp were obtained from the genomic DNA of the cows. Out of 200 examined cows, 26 cows (13.0%) were found to be CVM carriers. Wild type cows showed amplification with the G-specific primer pair but not with the T-specific primer pair, while carrier ones showed amplification of both the G- and T-specific primers, exhibited two DNA bands of 395 bp. Based on the clinical history of the cows, lowered reproductive performance was noticed in carrier ones. Out of four crossbred F1 calves (Holstein x Japanese Black), two were CVM carrier. Crossbred F1 could inherit the CVM defect when Japanese Black semen used to inseminate a carrier Holstein cow. In conclusion, the study reports the occurrence of CVM among Holstein cows in Hiroshima Prefecture, Japan; moreover, it describes the first cases of CVM in crossbred F1 generation.