The ration of the dairy cow is used for maintenance, growth, the formation of body fat, the building up of the foetus and milk production, so the problem of feed utilizaton is a complicated one. 'rhe maintenance ration is more easily studied than are the requirements for growth and productive purposes and yet many of the factors controlling it are not thoroly understood.

Condition in dairy cattle has received little attention in investigational work and its influence on the maintenance requirements of animals has not been studied. In fact, the influence of condition on the maintenance requirements of all classe~ of farm live stock has been somewhat neglected. Yet the results of the investigation on dairy cattle here reported show that maintenance requirements for cows. in high condition are higher than for cows in low condition.