Changes in selected biochemical parameters (including FGF21) during subclinical and clinical ketosis in dairy cows

Negative energy balance (NEB) is a common pathological cause of ketosis. As the major organs of lipid metabolism, the liver and fat tissue take part in regulating lipid oxidative capacity and energy demands, which is also a key metabolic pathway that regulates NEB development during the perinatal period. Fibroblast Growth Factor 21 (FGF21) is a novel metabolic regulator involved in the control of fatty acid oxidation and lipid metabolism during a prolonged negative energy balance. Our study determined a correlation between serum FGF21 and β-hydroxybutyric acid (BHBA) levels in dairy cows with ketosis. We used sixty cows with low milk yield, abnormal glucose metabolism, and ketosis. Serum FGF21 and BHBA levels were measured using commercial kits. Serum FGF21 increased with increasing BHBA levels up to 1.6 mmol/L. At BHBA levels > 1.6 mmol/L, FGF21 decreased. Serum FGF21 levels were positively associated with BHBA levels, particularly in dairy cows with subclinical ketosis (r = 0.647, P < 0.01). At BHBA levels between 1.2 mmol/L and 1.6 mmol/L, FGF21 was more closely correlated with BHBA than with other metabolic parameters. At BHBA levels > 1.6 mmol/L, the association between FGF21 and BHBA was not significant. In conclusion, our results show that FGF21 was closely related with SK in cows. FGF21 may be a promising regulator in the prevention of subclinical ketosis.