10 THE SCIENTIFIC FEEDING OF ANIMALS ^ , 



cases to the extent of 44 per cent of the total nitrogen content). The salts 

 of ammonia occur in fermented feeding stuffs (silage and so-called brown 

 hay). Traces are also found in natural feeding stuffs. The physiological 

 action of these salts in small quantities probably resembles that of the 

 amids. (Zuntz, Morgen, Kellner). Large quantities are diuretic and 

 even toxic (nitrates). 



IV. The Fats 



The fats, with the carbohydrates, constitute the group of nitrogen-free 

 organic substances. 



The fats are esters of glycerin €3115(011)3, and of several fatty acids, 

 among which palmatin CjeHgoOg, stearin CigHggOa, and oleic acid Cjg 

 H34O2 are the most common. When the first two acids named are in ex- 

 cess the fat is firm (tallow); when oleic acid is in excess the fat is fluid 

 (oils). Free fatty acids make their appearance in the seeds of oil-produc- 

 ing plants, harvested before maturity, or in sprouted seeds of the latter, 

 as well as in feeding stuffs rich in fat and stored in damp places (oil cake, 

 etc.), imparting a sour odor and an acid taste. Further decomposition 

 produces rancidity. 



The amount of fat in vegetable feeding stuffs, as compared with other 

 carbohydrates is comparatively small. Comparatively few seeds are rich 

 in fat (oil-producing seeds, up to 50 per cent; oats and corn, 6 to 7 per 

 cent ; wheat and rye bran, 3 to 4 per cent, some legumes ; (peas, 3 per cent ; 

 lupines, 6 to 7 per cent) ; oil cakes had 8 to 12 per cent ; meat meal, 10 to 15 

 per cent. Green fodder and roughage and all tuber and root crops are de- 

 cidedly poor in fat content. In the animal body, on the other hand, the 

 fats are far in excess of the other nitrogen-free compounds (carbohy- 

 drates). 



The fat content is usually ascertained by extracting it from the feeding stuff with 

 ether or petroleum ether, evaporating the ether and weighing the residue, (Fig, 3). 



The crude fat thus obtained contains in admixture other ether-soluble 

 substances like cholesterins, lecithins, vegetable wax, chlorophyl, ethereal 

 oils, resins, etc., which are occasionally present in considerable quantity. 

 Thus the crude fat of the rough forages contain no less than 60 per cent 

 of these ether-soluble nonfatty substances. 



Among the ether-soluble nonfatty substances the phosphorus-containing 

 lecithins are valuable nutritive substances. The cholesterins are less valu- 

 able, and the resins probably possess no value at all. The lecithin con- 

 tent of the chemical dry matter of vetches amounts to 1.1 per cent; peas, 

 1 per cent ; hulled yellow lupines, 2,2 per cent ; wheat, 0.4 per cent ; bar- 

 ley, 0.5 per cent; Indian corn, 0.25 per cent; flaxseed, 0.7 per cent; hemp- 

 seed, 0.85 per cent ; peanut cake, 0.2 to 0.4 per cent ; sesame cake, 0.5 per 

 cent ; linseed cake, 0.44 per cent ; cocoanut cake, 0.3 per cent ; cottonseed 

 cake, 0.5 per cent. Most ethereal oils possess bactericidal properties. 

 Thus the oil of mustard checks the growth of bacteria in solutions of 1 

 to 3,000. The ethereal oils are widely prevalent in the seeds of Cruciferae, 



