
A STUDY OF RATIONS FED TO MILCH COWS. 93 
- give the calculated weights of digestible protein, fats and carbo- 
hydrates. As explained on page 74, these weights are calculated 
from the total nutrients by the use of factors (digestion coeff- 
cients) obtained from digestion experiments. These factors are 
only approximate, and the weights of nutrients obtained by their 
use are also approximate. 
In order that a ration may be complete, there must be enough 
digestible protein supplied in the food to build new tissues (bone, 
muscle, milk, etc.) and repair the wastes of the body, and suffi- 
cient digestible fat and carbohydrates to furnish heat and muscu- 
lar energy. If the sum of the digestible carbohydrates and two 
and one-fourth times the digestible fat of a ration is divided by 
the amount of digestible protein in the ration, the quotient gives 
what is called the nutritive ratio. If the quantities of digestible 
fat and carbohydrates are large relative to the protein, this num- 
ber will be large and the ration is called a “ wide ration;” if the 
quantities of digestible fat and carbohydrates are relatively small, 
the quotient is a small number and the ration is a “narrow”’ 
one. A ration where the nutritive ratio is much more than 1:6 
may be called a ‘“‘ wide ration;’’ if much less it may be called a 
“narrow ration.” ‘‘Wide rations” are much more common 
among American feeders than are ‘“‘narrow” ones. The column 
next to the last contains the nutritive ration of the rations fed. 
The last column contains the total energy (fuel value) of the 
digestible nutrients in the rations. These figures were obtained 
by calculation as explained on page 17 of the present Report. 
DISCUSSION OF THE RESULTS OF THE TESTS. 
The results brought out in sucha study as the one here reported, 
are tentative rather than final. This investigation was not under- 
taken with the expectation of obtaining startling facts nor would 
we be warranted in drawing very definite conclusions from the 
tests. We do believe, however, that there is much of practical 
importance to be obtained along this line of inquiry, and that the 
results herewith presented merit the careful attention of dairy- 
men. 
It is probably true that the animals of most of the herds ex- 
amined were, so far as breed, milk and butter product are con- 
cerned, above the average of cows kept for dairy purposes in 
Connecticut. It is doubtless true that the feeding practiced by 
the owners of these herds is better than that which is generally 
