CHAPTER XIX 

 FEEDING STANDARDS: THEIR ORIGIN AND USE 



The chemical composition of a feeding stuff is easily 

 learned by a chemist. He takes a fair sample of the feed and 

 grinds it in a mill to a powder as fine as flour. He then takes 

 a small sample of this and analyzes it in the laboratory. He 

 dries a weighed portion in an oven and finds just how much 

 water it contains, and what the percentage of dry matter. 

 Then with ether he dissolves out the fat, (ether extract) 

 and weighs this. With other chemicals he also separates out 

 the protein, the nitrogen-free extract, and the fiber. Another 

 sample of the feed he burns to learn how much ash or mineral 

 matter remains. Thus the chemist is able to determine just 

 how many pounds of each of these substances there are in a 

 given amount of feed. This is the first step taken by the 

 chemist in studying the value of foods for animals. 



The amount of digestible nutrients in a food, the simple 

 chemical analysis, however, did not show. This led to another 

 step forward by the chemist, whereby he learned just how 

 much of the total protein, carbohydrates, and fat in a given 

 food an animal digested. After analyzing a sample of the feed, 

 as much of it was fed as the animal would eat in a given time. 

 During the experiment, all the solid and liquid excrement 

 passed off by the animal was collected, and samples of these 

 were also analyzed. Having learned how much protein, 

 carbohydrates, and fat were lost in the manure, the chemist 

 deducted these amounts from the total amounts consumed 

 in the feed, and the difference was considered the amount 

 digested by the animal. This method was not perfect, but 



