182 CHEMISTRY OF FARM PRACTICE 



dry feed consumed will form 6.2 pounds of increased weight 

 in cattle, 8 pounds in sheep, and 17.6 pounds in hogs. An 

 inspection of the quotations from the various stock markets 

 will show that on this basis pork is the most profitable meat 

 to produce. 



125. Milk-Cows' Ration. The Wolff-Lehmann standards 

 advise for milk-cows a nutritive ratio of 1 to 5.7 (i.e., digesti- 

 ble protein 1 part, digestible carbohydrates+(2.25Xfat) 

 = 5.7 parts). For a cow that is expected to give 22 quarts 

 of milk, 29 pounds of dry matter is recommended per 1000 

 pounds of live-weight. The narrowest ration that is recom- 

 mended in these standards is recommended for milk-cows. 

 The feed of a dairy cow must of necessity contain a consider- 

 able amount of concentrates which are high in price compared 

 with roughages; but the value of the product will warrant 

 the increased expenditure. In calculating a ration, it is 

 not always practicable to get the exact ratio within the 

 prescribed number of pounds of dry matter. If possible, 

 the number of pounds of dry matter should be under rather 

 than over the standard, because the digestive organs of a 

 highly specialized animal should not be overtaxed. The 

 dairy cow is essentially a machine for the transformation 

 of feed into milk; hence every effort should be directed to a 

 large production per animal so as to reduce the cost of main- 

 tenance rations as low as possible by having fewer animals 

 to maintain. With this end in view, the dairy cow, when in 

 milk, should receive an abundant supply of concentrates 

 even if she has a good pasture. While dry, she can be 

 maintained like other animals, largely on roughage. 



126. Ration for Work Animals. The activity of the 

 muscles during the performance of work greatly increases the 

 amount of food required above a maintenance ration. It 

 has been shown by repeated experiments that energy 

 is derived most cheaply through the oxidation of carbohy- 

 drates and fats in the body; that a sufficient supply of car- 

 bohydrates and fats is an adequate source for all the energy 



