12 



PRINCIPLES OF FEEDING FARM ANIMALS 



Fats are organic compounds consisting largely of mixtures of 

 fatty acids, combined with glycerine (so-called glycerides) . The 

 more common fats are stearin, palmitin, and olein. The last-men- 

 tioned glyceride is liquid at ordinary temperatures, and, if present in 

 large quantities, renders the mixed fat liquid or very soft. Linoleic 

 and linolenic acids are also found in the seeds of some plants, like 

 flaxseed and soybeans; on exposure to the air in a thin layer, they 



10 



20 



25 



30 



35 



Fig. 3. — Fats in common feeding stuffs, in per cent. 



take up oxygen and " set," i.e., they dry and harden. This difference 

 in the behavior on exposure to the air is characteristic of drying and 

 non-drying oils. 



Some seeds contain large proportions of fat (oil), while others, 

 e.g., some of the cereals, are low in fat (Fig. 3). The coarse feeds 

 contain other materials than fat which -are soluble in ether, the 

 solvent for fat used in chemical analysis, viz., chlorophyl and various 

 resinous substances. The ether extract, in the case of these feeds, 

 is, therefore, not as pure fat as that from concentrated feeds. The 

 following figures show the average percentages of fat present in 

 various feeds: 



Concentrates Per cent 



Rice 0.4 



Wheat, barley, buckwheat 1.8 to 2.2 

 Indian corn and oats .... 5.0 to 5.4 



Soybeans 17.2 



Flaxseed 33.7 



Cotton seed 36.6 



Coarse feeds Per cent 



Soiling crops 0.3 to 2.1 



Hays 1.7 to 3.6 



Straws 1.2 to 2.3 



Roots 0.1 to 0.4 



Corn silage 0.9 



