Liver protein expression in dairy cows with high liver triglycerides in early lactation.

Fatty liver is a frequent subclinical health disorder in dairy cows that may lead to disorders related to the liver function. However, the effect of triglyceride (TG) accumulation on liver metabolic pathways is still unclear. The objective was, therefore, to characterize quantitative differences in the liver proteome between early lactation dairy cows with a low or high liver TG content. The liver proteome analysis indicated that a high liver TG content in early lactation dairy cows is associated with increased oxidation of saturated fatty acids, oxidative stress, and urea synthesis and decreased oxidation of unsaturated fatty acids. Furthermore, liver gluconeogenesis is apparently not impaired by an increased liver TG content. Based on correlations between liver proteins and plasma components, we suggest that future studies investigate the sensitivity and specificity of plasma aspartate aminotransferase, β-hydroxybutyrate, total bilirubin, total bile acids, and γ-glutamyltransferase for potential use as blood-based biomarkers for early detection of fatty liver in dairy cows. Our study is the first to study the proteome of dairy cows with naturally occurring fatty liver in early lactation.