44O PRINCIPLES OF AGRICULTURAL CHEMISTRY 



other chapter. The nutritive ratio given in the table is the ratio 

 of protein to non-protein, and not of proteids. 



Coarse feeds are largely used for maintenance purposes. As 

 they almost invariably contain enough phosphoric acid and lime 

 to supply the needs of the animal, the ash needs little attention. 

 Such an animal requires per 1,000 pounds live weight about 45 

 grams of lime and 22 grams of phosphoric acid in the food. 



Utilization of Nutrients for Production of Fat. The object of 

 fattening the animal is to finish it for market. Some of the facts 

 and principles upon which the fattening rations are based will be 

 discussed. Only the food fed in excess of maintenance require- 

 ments may be used in fattening. In the preceding chapter, we 

 not only had the evidence that proteids, crude fiber, fat, and 

 nitrogen-free extract could furnish fat, 1 but also the quantity of 

 fat which each could produce. Other methods of experiment 

 have been used to ascertain whether the nutrients of the food 

 may be used for the production of fat. 



Hoffman 2 fed a dog (previously starved for some days) on 

 370.8 grams of fat, and 49 grams of proteids (lean meat) per 

 day. In five days the animal gained 4.2 kilograms and then con- 

 tained 1352.7 grams of fat. The amount of fat present at the be- 

 ginning of feeding was estimated at 150 grams as ascertained by 

 examination of the dog. The maximum quantity that could have 

 been formed from the proteids fed was 130.5 grams. The re- 

 mainder of the fat, at least 1,072 grams, must have come from 

 the fat eaten. 



The following experiments of Soxhlet 3 show that carbo- 

 hydrates may form fat. Three pigs 5 to 6 months old were first 

 fed alike for 321 days. One was killed then and the body sub- 

 jected to analysis to ascertain its fat content. The remaining 

 two were fed on steamed rice for 75 days and 82 days, 

 respectively, the nutrients digested being determined by analysis 

 of food and excrement as in digestion experiments. The animals 



1 Soskin, Exp. Sta. Record 8, p. 179. 

 - Landw. Versuchs-stat., 1894. p. 475. 

 :i Centralblatt f. Agr. Chem., 1 88 r, p. 57.1. 



