Principles and Practice of Stock Feeding 13 



to a true average. The proportions digested, expressed as percentages, are 

 termed " digestion coefficients." The conduct of a digestion experiment, 

 although stated thus simply, requires much labor, is open to many errors 

 and difficulties, and the results are sometimes unsatisfactory. 



A survey of digestion coefficients shows wide variations in different 

 materials. From 6 to 94 per cent protein, from 29 to 100 per cent nitrogen- 

 free extract, and from 19 to 100 per cent ether extract is found to be digest- 

 ible in different foods. 



DIGESTIBLE NUTRIENTS 



The amounts of digestible nutrients in a given ration are determined 

 by multiplying the percentages of crude nutrients by their respective diges- 

 tion coefficients. The products are the pounds of digestible nutrients in 100 

 pounds. The calculation of clover hay is given as an example. 



Crude Crude Crude Nitrogen- Ether 

 Water Dry matter ash protein fiber free extract extract 



Analysis 15.3 84.7 6.2 12.3 24.8 38.1 3.3 



Digestion co- 

 efficients .57 .58 .54 .64 .55 



Digestible nu- 

 trients 48.3 7.1 13.4 24.4 1.8 



5. CONCERNING TABLES OF ANALYSES, DIGESTIBLE INGREDIENTS, ETC. 



Accompanying this bulletin — as an appendix — pages 37-56 — will be 

 found a glossary of definitions of the terms used and tables showing : 



Table I. Feeding standards. 



Table II. Average composition — both as feed and as fertilizer — of the 

 feeding stuffs most commonly used in New England. (With but few ex- 

 ceptions analyses of samples are from American sources. ) 



Table III. Digestion coefficients determined by American experiment 

 stations and digestible ingredients of the feeding stuffs in table II. 



Table IV. The pounds of total dry matter, of total organic matter and 

 of digestible protein and carbohydrates — with nutritive ratios — in varying 

 weights of fodders and feeds. 



This latter table is essentially a convenience table, eliminating from the 

 calculation of a feeding ration all but the 'final additions and simplifying 

 so far as possible the mathematics needed in figuring a ration. 



The data of analyses given in table II as indicated therewith are selected 

 from several sources. They represent the feeding stuffs in use today 

 in this section of the country better than any other set of tables known to 

 the writer. This is particularly true as regards certain concentrated 

 byproducts in large use in New England. Changes in method of manufac- 

 ture have been such that the analyses of five and ten years ago differ decid- 

 edly from those of the goods sold to-day under the same trade names. The 



