In the past few years a remarkable new interest in the breeding of dairy cattle has come to be shown in Great Britain and, as a result, renewed attention has been focussed on the subject down for discussion to-day. I think there are two main causes of this new interest. The first is the certainty—for as far ahead as we can see—that milk is likely to remain agricultural product No. 1. With this has come the conviction that to ensure efficient production at the source we have to introduce more certainty into our methods of breeding for milk. The poor level, by any standards of breeding efficiency, of a great number of our dairy herds has been one of the revelations of the war years; there is now factual evidence for what has been suspected for a long time.