DAIRYING 93 



It has been proved by experiment that the 

 maintenance diet of an average Shorthorn 

 cow, when dry, is fourteen pounds of digest- 

 ible dry matter. 



When in full milk and fattening, she re- 

 quires nearly twenty-five pounds. An animal 

 is like a machine, in that it is no more able 

 to create within itself the power of doing 

 work or of secreting milk than an engine 

 would be if not supplied with fuel and water. 

 The nutritive portion of food is divided 

 into : 



(1) Protein, or nitrogenous matter, made up 

 of albuminoids. These are the only parts of 

 food which are capable of building up the 

 animal tissue of the body, repairing the daily 

 wear and tear of bone, muscle, blood, etc. 



(2) Carbo-hydrates. Such as sugar, starch, 

 digestible fibre, are heat and fat producers, 

 heat being necessary to supply the energy of 

 the animal body. 



(3) Fats and oils. --These are of the same 

 use as carbo-hydrates, but fat produces nearly 



