Ketosis

Ketosis is an excess of ketone bodies in blood, milk and urine, caused by heavy mobilisation of body fat when energy intake does not meet demand. Clinical cases go off grain, lose condition and drop in milk. Subclinical ketosis is far more common and is usually defined by blood beta-hydroxybutyrate of 1.2 mmol/L or more.

Most cases occur in the first weeks after calving. Cows that calve over-conditioned are at greater risk.

Written for the 2026 edition of the library.