I started working at this dairy at the beginning of summer. They had ran out of silage so all summer the cows were on alfalfa hay. All summer we never once had a case of milk fever. But then this fall the cows went back on silage and every cow to calve since then have all had milk fever. The vet has been out and looked at the cows and has seen nothing unusual. A nutritionist tested the feed and said everything was good. But why would every cow keep having milk fever. Alfalfa hay has been known to cause milk fever, but all the cows that were on it all summer never once had a case. But these cows calving now were never on alfalfa hay. Does anyone know what could be wrong? I can tell you that the dry cows before coming in the calving barn were out on pea stubble. And the cows are brought into the calving barn a month in advance to adjust to the feed and everything else.