The Nutritive Ratio 51 
amounts of water, like fresh forage, silage, fruits, 
roots, etc. So well is this recognized that many 
dairymen find it economical to provide a regular sup- 
ply of succulent foods for their cows in milk, even 
though the nutrients in such foods cost more than 
similar amounts would in the dry state. 
In all the .studies and investigations that have 
been made with respect to the nutrition of domestic 
animals, no one has received more attention than the 
relation of the proteid, or nitrogenous part of the 
nutrients, to the non-protein part. Disregarding the 
protein supply so far as the maintenance of the 
animal is concerned (and a certain amount of protein, 
as is well known, is requisite to maintain life), 
there are considerable amounts of protein in the 
milk, the most important being the casein and albu- 
men of the milk, which together comprises more than 
3 per cent of the milk or about 25 per cent of the 
milk solids. This protein, of course, must come from 
the protein supply in the food. The problem of fur- 
nishing sufficient protein in dairy foods has been 
greatly simplified by the introduction of certain by- 
product commercial foods that are now abundant on 
the markets, so that it is no longer difficult, nor 
very expensive, to provide a sufficient amount of pro-. 
tein, and it is found that it is not necessary to “bal- 
ance” the proteid and non-proteid nutrients so care- 
fully as formerly. This balance is ordinarily ex- 
pressed by the nutritive ratio, and a dairy ration is 
now considered at least fairly satisfactory if the nutri- 
tive ratio falls anywhere between 1:4.5 and 1: 6.5. 
