306 DOMESTIC ANIMALS, DAIRYING, ETC. 



But notwithstanding all this, the foregoing data can afford val- 

 uable aid to the feeder. By their use he can get a general idea of 

 the feed requirements of his animals and can compute a ration 

 which will approximately supply the requisite amounts of protein 

 and energy. His ability as a feeder will be shown, first, in his 

 power to estimate the conditions which will modify the feed require- 

 ments of his particular animals and cause his feeds to vary from the 

 average, and, second, in the skill with which he can interpret the 

 daily results and modify his feeding in accordance with them. 



The problems given on the following pages are intended simply 

 as illustrations of the method of using the tables and not as model 

 rations. Limitations of space forbid the multiplication of examples, 

 but the reader who grasps the method will have no serious difficulty 

 in applying it to his own conditions, while facility will be required 

 with surprising rapidity by practice. It will be observed that the 

 form of these tables and the methods of computation do not differ 

 materially from those which have been used for many years in com- 

 puting rations on the basis of digestible nutrients, although the sig- 

 nificance of some of the figures is different. It may be added that 

 the digestible protein in the tables is true protein that is, it does 

 not include the so-called "amids" of the "crude protein." Con- 

 sequently the percentages, as well as the amounts estimated in the 

 rations on succeeding pages, are somewhat smaller than in the older 

 tables. 



Total Feed Required. A bunch of feeders 2 to 3 years old, 

 averaging 1,000 pounds per head, are to be fattened on clover hay 

 and corn-and-cob meal. Such cattle, if of good grade, should weigh 

 1,400 pounds each when ready for market and should not require 

 over two hundred days to make the gain of 400 pounds. They 

 should therefore make an average gain of 2 pounds per day. 



On page 301 it was estimated that a gain of 1 pound live weight 

 requires about 3.5 therms energy value in the feed ; for a daily gain 

 of 2 pounds, therefore, the energy requirement would be 7 therms. 

 To this must be added the maintenance requirement, which will in- 

 crease as the animals grow heavier. For the average weight of 1,200 

 pounds it is sufficiently accurate to use the maintenance requirement 

 computed in the table on page 299 for 1,250 pounds, viz., 7 therms. 

 This makes the total energy requirement per day 14 therms on the 

 average of the whole feeding period. 



If we assume that 2 pounds of grain will be fed for each pound 

 of hay, it is easy to compute from figures given on the foregoing 

 pages, the amount of feed required to supply 14 therms of energy, 

 as follows: 



Therms. 



In 100 pounds of clover hay 34.75 



In 200 pounds of corn-and-cob meal. 144.10 



In 300 pounds of feed 178.85 



In 1 pound of feed 596 



