Subclinical ketosis is characterized by elevated levels of ketone bodies in blood, and it is one of the most common metabolic disorders in dairy cows during early lactation. Cows with ketosis reduce their dry matter intake and are more prone to develop other diseases such as metritis, and displacement of abomasum. Moreover, they decrease production and reproduction performance during the lactation. Therefore, careful monitoring of ketosis in dairy cows is vital for keeping cow health and productivity.
Ketosis is measured by determining the level of β-hydroxybutyrate, a ketone body, in blood, urine or milk either in the laboratory or using cow-side ketosis test in the farm. Recently, β-hydroxybutyrate levels are being measured in milk samples collected from routine Dairy Herd Improvement (DHI) visits using infrared testing.