8 N. H. EXPERIMENT STATION [Bulletin 213 



We have this data for the pure grains and feeds, but because 

 the various proprietary feeds are not standardized there are no 

 data available for them. 



HOW TO USE TABLE 3 



Only the digestible nutrients are of value and so in compar- 

 ing two feeds we should compare just the digestible nutrients. 

 Suppose we had a cottonseed meal which analyzed 38 per cent 

 protein. The table shows cottonseed protein to be 84 per cent 

 digestible. We then would have 84/100 of 38 lbs., or 31.9 lbs. 

 of digestible protein per 100 pounds. If a wheat bran analyzed 

 15 per cent protein we see from the table that it is 78 per cent 

 digestible and we would have 78/100 of 15 or 11.7 lbs. of digest- 

 ible protein. The cottonseed meal would have 31.9 lbs. compared 

 with 11.7 in wheat bran. 



HOW TO FIGURE THE COMPARATIVE VALUE OF 

 FEEDS FROM THE CHEMICAL ANALYSIS 



Because such factors as palatability, quality of protein, di- 

 gestibility, etc, play an important part in determining the value 

 of feeding-stuffs it is difficult to make an exact comparison of 

 their value from a chemical analysis. The analysis will, how- 

 ever, serve as a very valuable guide. Since the farmer can 

 usually raise carbohydrates cheaper than he can purchase them, 

 he is chiefly interested in buying the concentrated feeding-stuffs 

 for their protein and fat content. 



Feeds may be compared upon the basis of the number of 

 pounds of protein and fat one dollar will buy. An example is 

 as follows: Feed number 48 sells for $5.00 per 100 pounds and 

 is guaranteed protein 25 per cent and fat 5 per cent. If it con- 

 tains 25 per cent protein there are 25 pounds of protein in 100 

 pounds of feed costing $5.00. Then one dollar will buy 25 

 divided by 5, or 5 pounds of protein and 5 divided by 5 or 1 

 pound of fat. Feed number 239 sells for $2.40 per 100 pounds 

 and is guaranteed 24 per cent protein and 5 per cent fat. Then 

 one dollar buys 24 divided by 2.40 or 10 pounds of protein and 

 5 divided by 2.40 or 2.1 pounds of fat. 



