Proceedings of Seventeenth Normal Institute 175 



tillers dried grains and gluten feed were, on the basis of total 

 digestible nutrients, relatively as cheap as com meal and hominy, 

 and actually nearly as cheap. This on the face of it shows that 

 there is no need of putting less protein into the ration than the 

 amount indicated by a nutritive ratio of 1:6, because total feed 

 value is just as cheap in these high protein feeds as in any other 

 feeds. This will hold for any year in the opinion of the writer. 

 Therefore the thing for every feeder to do is to prepare a table 

 like Table I from the list of concentrates that may be purchased. 

 Then choose from this list those foods which will bring the 

 nutritive ratio of his ration between 1:45 and 1:6, making the 

 choice from those which will yield total digestible nutrients the 

 cheapest. It is understood that such ,a choice will always be 

 modified by a careful consideration of the mechanical condition 

 and effect on the class of animals being fed, and all other con- 

 siderations of this character. The point is that, under the present 

 condition of the feed market, enough high protein feeds will be 

 found among the five or six feeds, which are relatively the cheap- 

 est, to properly balance the ration. 



2. MANURIAL values 



A consideration of the manurial values of feeds is important in 

 its bearing on the questions discussed under the cost of digestible 

 nutrients. 



The net cost for milk production of a feed under any system 

 of permanent agriculture is the first cost minus the value of the 

 fertilizer constituents appearing in the manure from that feed. 



If the urine and solid manure of the cow is properly conserved 

 75.5 per cent of the nitrogen (N) and 89.7 per cent of the 

 phosphoric acid (P2O5) and potash (KoO) is returned to the soil 

 from that in the feed. The rest of the nitrogen, phosporic acid 

 and potash appears in the milk. Obviously, since the mature cow 

 is neither gaining nor losing live weight, these are the only two 

 outlets for the materials taken in in the feed. 



Table II gives the amounts of nitrogen, phosphoric acid and 

 potash appearing in the solid and liquid manure from a mature 

 cow producing milk; These amounts are calculated by multiplying 

 the amounts available in the feed, if it were spread directly on 



