78 PRINCIPLES OF FEEDING FARM ANIMALS 
dairy cows at least, and the same doubtless holds true also for other 
classes of farm animals. Of the rations experimented with, only 
those composed entirely of corn feeds (corn meal, gluten feed, and 
_cornstalks) proved satisfactory for dairy cows (see p. 166). 
Fifth, the local market prices of feeding stuffs are of the greatest 
importance in determining which feeds to use; the conditions in the 
different sections of our continent are so different in this respect as 
to render generalization difficult. As a rule, nitrogenous concen- 
trates are the cheapest feeds in the South and the East, and flour- 
mill, brewery, and starch-factory refuse feeds the cheapest in the 
Northwest. Where alfalfa or other leguminous crops form the main 
dependence of farm animals for roughage, nitrogenous concentrates 
need not be fed to the extent that is necessary where farmers depend 
on mixed hay,.corn fodder, and other non-nitrogenous forage crops. 
for feeding their stock. 
The feeding standards express the physiological requirements of 
animals for a certain production. The economy of systems of feeding 
based on the standards does not enter into consideration, nor is it 
possible to formulate feeding standards of general or permanent 
value that take into consideration the financial side of the question, 
since the market prices of feeds vary in different places and at dif- 
ferent times in the same places. But for the practical farmer the 
cost of feeds is a factor of vital importance. It is of little help to 
him to be told that he can secure a certain production of milk or meat 
by a special system of feeding if the prices of the different feeding 
scuffs called for make it impossible or unprofitable for him to adopt 
them in his feeding operations. ' However, the standards place before 
the feeder an ideal which he may approach as nearly as the special 
conditions by which he is surrounded will allow. The relative cost 
of different feeding stuffs must always be considered, and the choice: | 
of feeds with which to supplement home-grown forage crops and 
grain must be made accordingly. 
QUESTIONS 
1, Explain how a ration is calculated according to (a) the Wolff-Leh- 
mann standard; (6) the Armsby standard. 
2. Discuss the relative value of these two standards for (a) dairy cows; 
(6) fattening steers. 
3. Formulate rations for a 1000-pound dairy cow producing 20 pounds of 
4 per cent milk, according to (@) Wolff-Lehmann, (6) Armsby stand- 
ards, using the following feeding stuffs: Mixed hay, oats, and wheat 
middlings. 
. Explain the method of calculating nutritive ratios; give an example. 
. State the limitations of feeding standards. and give at least four pointa 
to be considered in formulating rations for farm ‘animals. 
. What is the difference between a physiological standard and a practical 
feeding standard? 
oe 
a 
