Milk Fever (Hypocalcaemia) and Dairy Cow Welfare

Milk fever is a metabolic emergency in dairy cows at calving, caused by acute hypocalcaemia as calcium demand for colostrum production outstrips supply.

Key Facts

Clinical milk fever affects approximately 5-10% of dairy cows around calving — subclinical hypocalcaemia affects 25-50% of cows
Signs range from muscle weakness and staggering to recumbency and complete inability to rise — untreated cows may die
Older cows (third lactation and above) are at highest risk due to reduced calcium mobilisation capacity
Oral calcium boluses given at calving and 12 hours later prevent subclinical hypocalcaemia effectively in high-risk cows

Welfare Considerations

Milk fever causes rapid, severe welfare deterioration — affected cows cannot rise, are cold to the touch and have impaired consciousness in severe cases. IV calcium treatment provides dramatic, rapid welfare improvement in most cases when administered promptly. Subclinical hypocalcaemia (without visible signs) causes chronic welfare impairment through increased risk of displaced abomasum, uterine infection and lameness. Prevention-focused transition cow management — particularly anionic salts or DCAD diets in the dry period — substantially reduces both clinical and subclinical incidence.

What You Can Do

Identify high-risk cows (older, high-yielding, Jersey breed) and prioritise monitoring at calving
Treat suspected milk fever immediately with IV calcium — do not delay to confirm diagnosis in recumbent cows
Administer prophylactic oral calcium boluses to high-risk cows at calving and 12 hours after
Implement DCAD diet management in the dry period to reduce hypocalcaemia incidence at the herd level