[Inadequate milk production in cattle caused by an incorrect diet; an example from practice].

The milk production per cow on a dairy farm did not increase to any appreciable extent during the past few years. Moreover, when a number of cattle were found not to be pregnant, this suggested mineral deficiency to the livestock owner. The diet of the animals was therefore examined at his request and some advice was offered on this basis. These recommendations resulted in an increase of the production per cow in a standard herd, averaging 3.2 units, during the following year. The production of milk fat and milk protein showed an average daily increase of 146 g per animal. Mineral deficiency as a causative factor was considered to be unlikely.