Subclinical Ketosis in Dairy Cows: The Hidden Welfare Burden

Subclinical ketosis affects 40-60% of dairy cows in early lactation and causes welfare harm that is largely invisible without systematic testing.

Key Facts

• Subclinical ketosis is defined as elevated blood or milk ketone bodies without clinical signs
• It affects 40-60% of cows in the first 2 weeks after calving in typical dairy herds
• Subclinical ketosis causes immune suppression, reproductive failure, and increased disease susceptibility
• Cows with subclinical ketosis have 3x higher risk of developing clinical ketosis, metritis, and displaced abomasum
• Routine blood or milk ketone testing detects subclinical ketosis before clinical disease develops

Welfare Considerations

Subclinical ketosis causes hidden welfare harm — affected cows show no obvious clinical signs but have elevated blood beta-hydroxybutyrate indicating pathological lipid mobilization and hepatic stress. The welfare consequences accumulate silently: immune suppression increases mastitis and metritis risk, reproductive cycle is disrupted delaying conception, and the risk of progressing to clinical ketosis with severe welfare consequences is dramatically elevated. Herd-level welfare assessment requires routine ketone testing rather than waiting for clinical disease to manifest. Blood or milk ketone testing programs in the first 2 weeks post-calving identify affected cows for targeted propylene glycol treatment, reducing both the current welfare burden and the risk of more severe subsequent welfare harms.

What You Can Do

• Implement routine blood or milk BHBA testing for all cows in the first 2 weeks post-calving
• Treat subclinical ketosis with propylene glycol drenching to reduce ketone burden
• Monitor prepartum body condition scores — overconditioned cows have highest subclinical ketosis risk
• Optimize transition period nutrition to reduce negative energy balance severity post-calving
• Record subclinical ketosis prevalence as a herd welfare key performance indicator