282 AGRICULTURE FOR COMMON SCHOOLS 



with 1 as the first term. For example, oats (see Appendix) 

 contain in every 100 pounds about 9.25 pounds of digestible 

 protein, 48.3 pounds of digestible carbohydrates, and 4.18 

 pounds of digestible ether extract or fat. Now 4. 18 times 2.25 

 equals 9.40; 9.40 plus 48.3 equals 57.70, and 57.70 divided 

 by 9.2 equals 6.1 +. Therefore, the nutritive ratio of oats 

 would be 1 : 6.2, which would be considered a medium ratio. 

 According to Dr. Jordan, of the New York Experiment 

 Station, a ratio less than 1 : 5.5 is a narrow ratio, above 

 1 : 8.0 a wide ratio, and anything between these two may 

 be considered a medium ratio. 



Many experiments have been made to determine how many 

 pounds of digestible nutrients an animal should receive in its 

 food each day, but the problem is largely unsolved. The 

 amount needed is influenced by a great many conditions, 

 some of the more important of which are the conditions and 

 purpose of the animal, its age, and the conditions of tempera- 

 ture under which it is kept. In general a young, growing ani- 

 mal, or cow giving a heavy flow of milk, needs a ration having 

 a rather narrow ratio, that is, a larger proportion of nitrog- 

 enous foods. A mature animal or one laying on fat requires 

 a ration of medium or wide ratio. 



Experimenters have attempted to arrange in tables the 

 digestible nutrients necessary for animals of various ages and 

 conditions. These tables are called feeding standards. How- 

 ever, practical men have not found these standards very use- 

 ful, and they are not generally used except as guides to intel- 

 ligent practice. The practical man must always study his 

 animals and the feed which he has available and so adjust 

 them as to get the largest returns possible in the most econom- 

 ical manner. 



