264 Agricultural Chemistry. 



ducing the largest return in butter fat, butter fat and casein, or 

 total milk solids per unit of food consumed. 



The transformation of digestible feed material into human food 

 by the dairy cow far exceeds that produced in the same time by 

 the growing or fattening ox and slightly exceeds that produced in 

 swine. An ox, gaining 2 pounds per day, will yield in edible 

 solids about 1.5 pounds, while a dairy cow, producing 30 pounds 

 of milk containing 12 per cent of solids, will yield 3.6 pounds. 

 Based on pounds of digestible nutrients consumed, Jordan has 

 given us some interesting figures. They are general averages 

 and are given in the following table ; they represent the pounds 

 of edible solids produced by 100 Ibs. of digestible organic matter 

 in the ration. 



Relation of Food to Produce. 



Edible solids 



Lbs. 



Milk 18.0 



Steers, (carcass) 2.52 



Lambs 2 . 60 



Swine 15 . 60 



Calves 8.10 



Fowl 4.20 



Eggs 5.10 



The quantity of solids in the cow 's milk, per unit of feed con- 

 sumed, thus always exceeds the quantity of solids produced in 

 the increase of the fattening ox, and in the order of food effi- 

 ciency the cow leads the list. 



Milk is a highly nitrogenous substance, and its proteins must 

 be made from, protein. They can have no other ultimate source 

 but the feed and cannot be produced from fats or carbohydrates. 

 Thirty pounds of average milk will contain a pound of protein. 

 This daily drain means that the ration of the dairy cow must 

 be reasonably narrow. If 0.6 pound of protein is needed for 

 maintenance, then 1.6 pounds must be used daily. Practice and 

 science have established the quantity of digestible organic matter 



