140 THE BUSINESS OF DAIRYING 



That the nutrient requirements in milk production 

 depend: 



1. Upon the weight of the cow. 



2. Upon the quantity of milk yielded. 



3. Upon the quality of the milk, and 



4. Upon the age of the cow. 



During the past few years we have analyzed some 

 2,000 milkings by the gravity process, and compar- 

 ing the composition of the milk with the nutrients 

 consumed in its production, we find that the net nu- 

 triment, that is, the nutriment in a ration available 

 for product, requires 1.75 of nutriment to one of 

 product yielded. That is, reducing the digestible 

 matter in the productive part of the ration to a com- 

 mon energy value, and the milk solids yielded to a 

 common energy value, it requires 1.75 units of nu- 

 triments to produce a unit of product. Whenever 

 a cow consumes more than this we find she gains in 

 weight, and if she receives less, she either shrinks 

 in milk or loses in body weight. Applying this gen- 

 eral rule in feeding practice, we find that in addition 

 to the food of maintenance a cow needs 1.75 of nutri- 

 ment to a unit of product. 



Some claim that some cows will yield more prod- 

 uct for a unit of feed than others. We find that such 

 is not the case if a cow is under normal condition. 

 The reason why they feed some cows more for a 

 unit of product than others, is that the cow will con- 

 sume the feed, though she does not need it, and it 

 takes several months for some cows to begin to 

 utilize the surplus nutriment in making body gain. 



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