138 THE BUSINESS OF DAIRYING 



For cow weighing 850 pounds and yielding 40 



pounds of 4 per cent, milk : 



Pro. C. H. Fat 



Nutrients for 40 lbs. of milk 1.87 8.56 .64 



Nutrients for 8.5 cwt. maintenance.. .59 5.95 .08 



Ration required 2.46 14.51 .72 



Nutritive ratio 1:6.5 



But if the cow weighing 12 cwt. yields 40 pounds 

 of milk per day and the cow weighing 8.5 cwt. yields 

 20 pounds, the nutrient requirements for their re- 

 spective rations according to table will be as fol- 

 lows : 



Pro. C. H. Fat 

 Nutrients for 40 lbs. of 4 per cent. 



milk 1 .87 8.56 .64 



Nutrients for 12 cwt. maintenance... .84 8.40 .12 



Required ration 2.71 16.96 .76 



Nutritive ratio 1 :6.8 



Pro. C. H. Fat 

 Nutrients for 20 lbs. of 4 per cent. 



milk 93 4.28 .32 



Nutrients for 8.5 cwt. maintenance. . .59 5.95 .08 



Required ration 1.52 10.23 -40 



Nutritive ratio i :7.3 



In prescribing rations upon the basis of flow and 

 quality of milk and weight of cow and using the 

 factors given in the table the nutritive ratio be- 

 comes a factor of very little importance the same as 

 is the case with dry matter in a ration. If the nu- 

 trients required or a given flow of milk are provided 

 for in the concentrates the food of maintenance may 

 be secured by feeding at least a portion of the rough- 

 age ad lib. If the grain mixture has a nutritive ra- 

 tio of I to 5 or 5.5 it will fairly meet the require- 

 ments. 



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