The window of opportunity for reducing milk fever of dairy cows is short
If systemic immune activation occurs during the transition to lactation of dairy cows, one of the defence mechanisms of a cow is to reduce her blood calcium levels. Cow colostrum and milk contain large quantities of calcium. The amounts of calcium that a cow needs directly after calving can therefore easily double. In response to this drop in blood calcium levels and this increase in calcium demand, dairy cows try to increase the uptake of calcium from the diet and they try to mobilise calcium from the bones. This requires a hormonal adaptation which takes about 2 days.