Dairy Cow Milk Fever Subclinical Hypocalcaemia Effects

Subclinical hypocalcaemia at calving affects far more cows than clinical milk fever. Its hidden welfare and production impacts make it a priority for nutritional management.

Key Facts

Subclinical hypocalcaemia occurs in 25-50% of multiparous cows without clinical signs of collapse
It impairs uterine contraction increasing retained fetal membranes and metritis risk
Immune function is suppressed by low calcium, predisposing to mastitis and other infections
Transition cow nutritional management targeting negative dietary cation-anion balance prevents it
Oral calcium supplementation at calving prevents post-calving calcium dips

Welfare Considerations

The welfare impact of subclinical hypocalcaemia is largely invisible at the cow level but measurable in herd reproductive and health performance. Cows experience impaired immune function, increased uterine infection risk and delayed resumption of reproductive cycling. These consequences cause welfare harm through infectious diseases and metabolic strain, even without the obvious suffering of recumbency. Proactive nutritional management and oral calcium supplementation at calving represent cost-effective welfare interventions with proven efficacy. Regular blood calcium sampling of fresh cows quantifies herd prevalence.

What You Can Do

Test blood calcium in 10 fresh multiparous cows per month to assess subclinical prevalence
Work with a nutritionist to design a transition cow programme targeting negative DCAD
Administer oral calcium boluses to multiparous cows at calving and 12 hours post-calving
Monitor uterine health and retained fetal membrane rates as proxy indicators of calcium status
Include transition cow calcium management in annual herd health plan reviews