Subclinical ketosis affects up to 40 per cent of dairy cows in early lactation, impairing immune function, reducing milk yield, and predisposing cows to clinical disease including displaced abomasum and clinical ketosis. Systematic monitoring and targeted management improve transition cow welfare.
Subclinical ketosis impairs neutrophil and lymphocyte function, meaning affected cows have reduced ability to fight uterine infections and mastitis during the period of maximum immune challenge. These secondary diseases cause significant suffering. The welfare impact of ketosis is thus not just the direct effect of elevated ketones but the cascade of painful diseases it predisposes cows to in early lactation. Welfare-centred transition management combines dry cow body condition scoring, appropriate dry period length, adequate transition diet formulation, and systematic fresh cow monitoring with ketone testing at three to five days in milk.