After birth, goats must provide large amounts of calcium with their milk. Does normally have enough calcium reserves in their bones. But, if a doe has been on a high-calcium diet during her dry period, her body may “forget” how to mobilize those reserves. If that happens, blood calcium levels may drop and result in milk fever.
Source: Purina Mills.
You can help address milk fever in goats by not feeding too much high-calcium feed, such as alfalfa, during late pregnancy. Grass hay or pasture is a much better choice during the dry period. If the doe’s body does not get all the calcium it needs in the feed, it will start pulling calcium reserves from the bones. By the time the doe gives birth and begins milking, the body is accustomed to quickly mobilizing bone calcium, and the doe will not suffer a potentially fatal drop in blood calcium.