PRINCIPLES OF STOCK FEEDING 



71 



with the amount required by the stand- 

 ard we see that the dry matter, protein 

 and carbohydrates are all deficient. Let 

 us add, therefore, about 10 pounds more 

 silage, 2 of bran and V/2 of linseed meal. 



This gives us a ration containing 

 about 25 pounds of dry matter, 2.59 

 pounds of protein, 12.6 pounds of car- 

 bohydrates and 0.6 pound of fat. 



This ration is still deficient in. dry 

 matter as compared with the standard 

 and contains a slight excess of fat. 

 Nevertheless it is approximately cor- 

 rect, and near enough to satisfy the 

 standard. It has been found that the 

 dry matter may vary from 10 to 20 per 

 cent from the standard either way with- 

 out affecting the efficiency of the ration. 

 The amount of dry matter, however, 

 could easily be increased by the addi- 

 tion of a few pounds of straw without 

 materially changing the nutritive ratio 

 or affecting the ration in other respects. 

 The method here given for calculating 

 rations is largely a cut and try method. 

 The amounts of each material to use 

 are largely guessed at until the right 

 proportions are found. It is the method 

 in common use by practically everyone 

 who uses these standards, and practices 

 the feeding of balanced rations. 



Calculating balanced rations by alli- 

 gation — There is, however, a mathemat- 

 ical way of calculating balanced rations 

 based on the old arithmetic principle of 

 alligation in which all guess work is eli- 

 minated. The rule of alligation, the 

 reader will remember, is the one followed 

 when required to mix together three or 

 four different priced articles like teas, 

 to produce a mixture having a uniform 

 price. 



The method of applying the rule of 

 alligation in balancing rations was first 

 presented by J. T. Willard, director of 

 the Kansas experiment station in Bul- 

 letin No 115 of that station. 



The system is based on the nutritive 

 ratios of feeding stuffs and on what the 

 author calls the "protein equating 

 factor." By this term is meant the num- 

 ber of pounds of a feeding stuff re- 



quired to contain 1 pound of digestible 

 protein. Thus, if a feeding stuff, A, 

 contain 5 per cent digestible protein, 

 65.5 per cent digestible carbohydrates 

 and 2.7 per cent digestible fat, the nu- 

 tritive ratio (determined by the method 

 described on page 66 is 1 :14, and the 

 protein equating factor (100-=-5 is 20; 

 that is, 20 pounds of this feed will 

 contain 1 pound of digestible protein. 

 In a similar manner let us assume that 

 the nutritive ratio of a feeding stuff, B. 



Fig. 45 A POPULAR KIND OF POWER 



FEED GRINDER FOR THE FARM 



is 1:6 and the protein equating factor 

 8. Now let it be required to mix these 

 two feeds so that the mixture shall have 

 a nutritive ratio of 1 :9. This is done by 

 alligation, as shown below. 



Now proceeding with the alligation 

 we find that the difference between 14 

 and 9 is 5. This is set down opposite 

 the feed, B, with which it is compared. 



Second term 

 of ratio 



Feed A -14 



Proposed mixture 9 



Feed B 6 



The difference between 6 and 9 is 3, which 

 is set down opposite feed A with which 

 it is compared. Now for each pound of 



Difference 

 3 



Protein equat- 

 ing 1 factor 

 X 20 



Mixture 

 necessary 

 60 



40 



5 X 8 



protein in feed A there are 20 (pro- 

 tein equating factor) pounds of non- 

 protein. Hence it would require 3 x 20, 



