Abstract
Subclinical ketosis in dairy cattle is associated with postpartum negative energy balance (NEB) and displaced abomasum, and it may develop into clinical ketosis. However, its incidence, causative factors and blood profiles other than ketone bodies are not well defined. We examined various blood parameters in 150 dairy cattle (52 with subclinical ketosis, 23 with clinical ketosis and 75 in good condition) in order to understand the pathophysiology of subclinical ketosis. Cows with subclinical ketosis showed lower blood glucose (GLU) and higher β-hydroxybutyric acid (BHB), non-esterified fatty acid (NEFA), triglyceride (TG), β-lipoprotein, total protein, aspartate aminotransferase (AST) and γ-Glutamyl transferase (GGT) compared to healthy cows. In contrast, they showed higher GLU, HDL-cholesterol, total cholesterol and phospholipids and lower BHB, NEFA, TG and AST compared to cows with clinical ketosis. In cows with subclinical ketosis, BHB was positively correlated with NEFA and AST, while a negative correlation was found between BHB and GLU and between GLU and AST. These data suggest that cows with subclinical ketosis have extensive mobilization of body fat and decreased liver function due to NEB compared to healthy cows, although their duration of NEB is shorter and NEB and liver dysfunction are milder than those in cows with clinical ketosis.
