

A STUDY OF RATIONS FED TO MILCH COWS. 97 
carbohydrates and fats are so abundant and so cheap in this 
country that we feed them liberally, does not imply, much less 
prove, that we are using them wisely.* 
We have so few American data upon the effects of rations, that 
the teachings of the sixteen studies here reported upon this 
question are of some value. 
In table 31 (page 99) are summarized the rations fed, together 
with the yield of butter-fat observed during the five days of the 
tests. The weight of butter-fat was selected rather than the 
weight of milk, as it is less liable to fluctuation from day to day, 
and also remains more constant during the earlier months of 
lactation. In this tabulation the butter yields of all the animals 
under two years of age, and which were more than eight months 
in milk flow, have been omitted. Also, in one or two instances, 
animals giving*unusually small yields were also omitted from the 
tabulations. The animals were of different breeds, and in many 
ways the conditions were such that the results are not strictly 
comparable one with the other, and yet in the lack of better data 
the results are here tabulated to show what light they throw upon 
the question of the effects of protein and the nutritive ratio upon 
the production of butter-fat. In this summary table, the figures 
are made to conform more nearly to ‘‘round numbers.” ‘Thus 
the weights of digestible protein are given to the nearest .o5 of a 
pound, 2.51 pounds being taken as 2.50, etc. 
The average butter-fat yields for the five days are grouped in 
accordance with the size of the nutritive ratio of the rations 
and the weights of protein fed. The butter-yields from the 

* After this article was in type and thegpreceding pages were printed, a Bulletin (Bulletin 38, 
Wisconsin Experiment Station, by F. W. Woll,) upon ‘‘ One Hundred American Rations for 
Dairy Cows,” was received. This Bulletin presents results of further observations upon dairy 
feeding similar to those described in Bulletin 33 of that Station. The rations fed were ob- 
tained in the same way as those of the earlier Bulletin. Letters were ‘‘sent to four hundred 
dairy farmers and breeders of dairy stock in all parts of the United States and Canada, asking 
information concerning their methods of feeding milch cows.’”? * * * ‘‘One hundred of the 
farmers to whom the circulars were sent furnished complete rations containing definite quanti- 
ties of the feeding stuffs fed daily to their cows, as exactly as the circumstances would 
permit.’ [The italics are ours. ] 
‘* Combining all of the rations which have been fed by successful dairy farmers and breeders 
in various parts of our continent, we have the following American ration’’: Dry matter, 24.51 
pounds, containing 2.15 pounds digestible protein, .74 pounds digestible fat and 13.27 pounds 
digestible carbohydrates. The nutritive ratio of this ration is 1 to 6.9, and the estimated fuel 
value of its digestible nutrients is 31,250 calories. 
This ration differs from the one given in Bulletin 33 of the Wisconsin Station by containing 
1.5 pounds less organic matter, .15 pounds less digestible protein, and its potential energy is 
gso calories less. The amounts of digestible protein in these rations ranged from rt.05 pounds 
to 4.34 pounds, the fuel value of the digestible nutrients ranged from 19,050 calories to 45,600, 
and the nutritive ratios varied from 1 to 4.1, tor to 12.8. 
7 
