308 PRODUCTIVE FEEDING OF FARM ANIMALS 
a safe rule to so by with regard to feeding grain to pigs on pasture: 
When the price of pork on foot at the farm is more than three 
times the price of grain, a rather heavy ration should be given; 
when the price of pork is five times or less than the price of grain, 
a minimum amount should be fed. 
The growing period of pigs will last until they are five to six 
months old, depending on the method of feeding practised, usually 
about five months old, when they will have reached a weight of 
nearly 100 pounds; they are then put on fattening rations. 
The Dietrich Standard for Pigs.—Dietrich concludes, from 
careful studies of the nutrition of pigs conducted during a series 
of years, that one and the same pig under different conditions may 
maintain its live weight on distinctly different quantities of the same 
combinations of feed. This variation appears to be due to the plane 
of nutrition upon which the pigs have been maintained previous 
to the time of making the maintenance experiment. He gives the 
maintenance requirements of pigs that have been previously kept 
on a low nutritive plane as follows: 
Dietrich Maintenance Standard for Pigs, Per Head, 100 Pounds Live Weight. 
Digestible crude protein Digestible carbohydrates Digestible fat 
0.10 pound 0.25 to 0.40 pound 0.03 pound 
The energy requirements of the ration are about 1.12 therms 
(p. 35) .78 
The rations given in the following table have been calculated 
according to the rather elaborate system of feeding pigs recom- 
mended by Dietrich: 
An Approximate Ration for Pigs Intended for Breeding Purposes 
Age of pigs in months 
Feeds 2 | 3 | 4 | 5 | 6 | 7 | 8 
Pounds of feed per 100 pounds live weight per day 
Corn.......... 2.7 2.8 2.9 2.9 3.0 3.3 2.9 
Soybeans (seed). A 5 A 4 4 A 7 
Skim milk...... 6.0 6.0 6.0 6.0 6.0 — — 
Water......... 7.1 6.4 5.7 5.1 4.4 9.2 8.5 
In the place of corn may be substituted rye, barley, wheat, rice, 
ete., and in the place of soybeans, linseed meal or peas, but in 
the latter case the quantity fed must be increased, as peas contain 
#Tllinois Bulletin 163; Circulars 126, 133, and 153, 
