High concentrations of non-esterified fatty acid (NEFA) and β-hydroxybutyrate (BHBA) in cows' blood caused by ketosis are associated with inflammatory states. We hypothesised that ketosis in postparturient dairy cows would result in altered levels on inflammation-related proteins not only in plasma but also in the milk fat globule membranes (MFGM). Thirty cows were selected from a dairy farm in Heilongjiang, China. Inflammatory milk fat globule membrane proteins were detected using ELISA kits, and a fully automatic biochemical analyser was used to measure the concentrations of BHBA, NEFA, glucose (GLU) and triglyceride (TG) in plasma. MFGM protein from milk of ketotic cows contained significantly different concentrations of acute-phase response proteins (complement C3 (C3), prothrombin (F2), alpha-1-acid glycoprotein (ORM1), inter-alpha-trypsin inhibitor heavy chain H4 (ITIH4), alpha-2-HS-glycoprotein (AHSG), complement C9 (C9), complement regulatory protein variant 4 (CD46)) in comparison with milk from non-ketotic cows. Blood concentrations of C3, complement C9 (C9), tumour necrosis factor α (TNFα), MFGM C3, monocyte differentiation antigen CD14 (CD14) and ORM1 levels were correlated with energy balance. ITIH4 and CD46 increased, and AHSG and ORM1 decreased before the onset of ketosis. These biomarkers offer potential as predictors and monitors of ketosis in at-risk cows.
Keywords: Dairy cow; inflammatory proteins; ketosis; milk fat globule membrane protein.