
THE CALCULATION OF RATIONS, 169 
the range of variation in composition. It is, I suspect, customary 
for those who use such tables to calculate their rations by assum- 
ing the materials they use to be of average composition and 
average digestibility. The great variability in composition of 
feeding stuffs, which a glance at the table will show, points out 
the unwisdom of blindly assuming a given feeding material to be 
of average composition. If it were practicable, the best method, 
when deciding upon a ration to be used, would be to have 
analyses made of the materials to be fed; but since this is not 
generally practicable, the farmer is left largely to his own judg- 
ment as to the quality of the food. ‘Tables showing the range in 
composition will help to a better estimate of the probable compo- 
sition of a given feeding stuff, when used with a knowledge of 
conditions of growth, than can be obtained in any way except by 
actual analysis. 
In estimating whether a feed is above or below the average 
composition and digestibility, some of the more important condi- 
tions affecting composition and digestibility should be taken into 
account. ‘They may be summed up as follows: 
Crops of grain, and fodder plants other than legumes, grown 
with nitrogenous fertilizers, will usually contain more protein 
than those grown with only mineral fertilizers. 
Fodders are equally digestible, whether fed green or dry, pro- 
vided there is no loss in curing. 
Quick curing without overdrying, and with a minimum of 
handling, reduces loss of leaves and other fine portions of the 
plant. Hay thus cured will usually be richer in protein and in 
fats than if there is much loss in curing. ‘The protein and fat are 
also more digestible in such hays than in those that are not care- 
fully cured. 
The method of preparation of a fodder, z..e, whether steamed 
before feeding or not, or whether fed hot or cold, so far as the 
experiments show, produces no effect upon the digestibility. 
As a rule, the older the plant, the less percentages of protein 
and fat and the more of fiber it contains. Also, the protein, fats, 
and carbohydrates are less digestible in old than in young plants. 
This points out the importance of comparatively early cutting. 
Probably the best time for cutting most plants used for hay is 
when they are in early bloom. 
