Variability of Osteocalcin Status in Chinese Holstein Cattle: Do Phylogeny, Vitamin D or Gene Polymorphisms Matter?

Osteocalcin (OC), a marker of bone turnover, displays patterns in relation to physiological and genetic factors. Here, we present an association study in a population of Chinese Holstein cattle (n = 24) with OC serum concentration as a phenotypic trait. We hypothesised that OC status is associated with phylogeny, vitamin D serum level and single nucleotide polymorphisms (SNPs). Mitochondrial DNA (mtDNA) was used as an unlinked marker to examine phylogeny and linkage to measured phenotypic traits of vitamin D and OC status. Following an association study with OC serum variability as the trait, genotyping of SNPs (n = 27) in OC-related genes was performed. Candidate SNPs were chosen in genes with an emphasis on the vitamin D and vitamin K pathways. Multivariant factor analysis revealed a correlation between vitamin D serum concentration and a SNP in the gene GC (rs43338565), which encodes a vitamin D-binding protein, as well as between a SNP in NFATc1 (rs42038422) and OC concentration. However, univariate analysis revealed that population structure, vitamin D serum levels and SNPs were not significant determinants of OC status in the studied group.