39 FUNDAMENTALS OF AGRICULTURE. 



Carbohydrates. This group of substances is not in- 

 cluded in the above classification, because the animal 

 changes the carbohydrates into fats and glycogen in 

 the processes of digestion and assimilation. 



COMPOSITION OF ANIMALS. 



Water Ash Protein Fat 



Steer, 17 months old 59-4% 4-4% i?-4% 18.8% 



Steer, 24 months old 53.1 5.1 16.6 25.2 



Swine, well fed 57.9 2.9 15.0 24.2 



Swine, fat 43.9 1.9 11.9 42.3 



Sheep, lean 67.5 4.0 18.3 10.2 



Sheep, very fat 43.3 3.1 12.2 41.4 



The data in the above table was worked out by 

 Lawes and Gilbert and the Maine Experiment Station. 

 It shows that lean animals contain a great deal more 

 water than fat animals. 



Lean and Fat Animals. The following table gives 

 the proportion of dressed carcass of lean and fat 

 animals, according to Lawes and Gilbert : 



Ox Sheep Swine 



Lean animal 47% 45% 73% 



Fat animal 60 53 82 



A fat animal contains less water than a lean animal, 

 because the increase in fat is made up largely of dry 

 matter. The fatty substances do not replace the water, 

 but an increase in fat in the animal body means a 

 greater increase in dry matter. 



The Nutritive Elements. Protein, fats, carbohy- 

 drates, water and ash serve to supply the needs of 

 animals. Protein, fats and carbohydrates are usually 

 called the nutritive elements. Water and ash are not 

 included. The water can be supplied in a cheaper 

 form than in a feed stuff, and there is generally suffi- 

 cient ash present in feed stuffs to enable us not to con- 

 sider this ingredient. 



Purpose of the Nutritive Elements. Animals use 

 food in two ways: i. To build up the body and repair 

 broken down tissue. 2. To produce energy, to keep 

 warm, and to supply that power which gives locomotion 

 or movement to the animal body. 



