It will thus be seen that all of the several groups of nutrients 

 — protein, carbohydrates and fat — are sources of energy; that 

 is, they furnish the food or fuel to maintain the life of the body. 

 They also are convertible into fat. The protein, however 

 (including the ash), is the only source of flesh or lean meat. 

 In order to form the bones all of the groups are used. 



2. Digestibility of Cattle Feeds. 

 The several groups of nutrients above described, which make 

 up the various cattle feeds, are valuable to the animal only in 

 so far as they can be digested and assimilated. The con- 

 centrated feeds are considerably more digestible than the 

 coarse fodders, as a single illustration will show : — 



In the first and fourth columns are given the composition 

 of average samples of timothy hay and of gluten feed. In the 

 second and fifth columns are shown the percentages of the 

 different groups which are digestible. Thus, of the 6.3 pounds 

 of protein in timothy, 48 per cent are digestible, or 3 pounds; 

 and of the 26.2 pounds of protein in 100 pounds of gluten feed, 

 85 per cent, or 22.3 pounds, are digestible. Excluding the ash, 

 which is not generally taken into account, it is shown that 100 

 pounds of timothy hay contain about 48 pounds of digestible 

 or actual food material, and 100 pounds of gluten feed 78 

 pounds. It is evident, therefore, that the gluten feed is de- 

 cidedly more valuable as a source of nutrition than the timothy 

 hay. 



