

THE DIGESTIBILITY OF FEEDING STUFFS. 165 
An examination of table 49, in which there are given minima 
and maxima as well as average digestion coefficients, will show 
that in many instances there is a great range in the digestibility of 
the same kinds of feeding stuffs. This was to have been ex- 
pected, since there are so many modifying elements entering into 
a digestion experiment. The kinds of animals used, their breeds, 
ages, and especially differences of individual animals, greatly 
modify the results. The methods of harvesting and curing, the 
period of growth at which the plant is cut, the length of time kept 
after curing, the quantities fed, whether fed green or cured, and 
the method of preparation of the food, all affect the digestibility 
of the feeding stuff and, moreover, mixtures of different feeds 
do not seem to be digested in the same way as the same feeds 
would be if fed alone. It follows from this, taken together with 
the comparatively small number of accurate digestion experi- 
ments thus far conducted, that it would not do to follow abso- 
lutely the figures of either tables 49 or 50. 
Looking at tables 49 or 50, one will find that different 
Species of grasses have in some instances very different digesti- 
bility. While it is probably true that there are specific dif- 
ferences in digestibility, it is very much to be doubted if the 
results of experiments thus far obtained would warrant us in 
assigning definite different coefficients of digestibility to different 
species of coarse fodders. In table 51, which follows, there is 
given a summary of the average coefficients of digestibility of 
tables 49 and 50. In this table (51), instead of arranging the | 
coarse fodders under their specific names, materials which are 
more or less alike are classed together. Thus, under green 
fodders, the different kinds of grass, rye and allied plants are 
grouped together. The numbers in the table immediately fol- 
lowing the words European and American refer to the reference 
numbers in the respective tables (49 and 50) from which the aver- 
ages were obtained. It is of considerable interest to note that 
while individual experiments (see table 49) upon the same species 
have quite different range of digestibility, that the average of 
results obtained in the groups, in both European and Amer- 
ican experiments, accord fairly well. ‘There are also given in this 
table (51) the factors which were used in calculating the pounds 
of digestible matter in different feeding stuffs, as given in table 
52. In the instances in which simply inspection of the table will 
not show how the factors used in table 52 were obtained, expla- 
nations are given in foot notes. 
