INPUT AS RELATED TO OUTPUT 
19 
quantity in the whole range of variation. Thus, as shown in Table 
20, while 10 pounds of grain per day resulted in a gain of 1.15 pounds 
per head, 20 pounds caused not twice this, but only 1.81 pounds gain, 
and 30 pounds but 2.10 pounds gain. Similar though not so marked 
decreasing gains were found for roughage inputs. 
Net Relations of Two Input Factors to Gain in Weight in Beef Animals 
CAIN 
IN WEIGHT 
PER DAY 
POUNDS 
2,0 
1.0 
2.0 
•1.0 
12 16 20 
POUNDS OF ROUGHAGE FED PER HEAD PER DAY 
Fig. 7. — The straight lines indicate what would be a constant increase in weight as 
heavier feeding is practiced. The curves drop off below the straight! line because of 
diminishing returns ; the heavier the rate of feeding, the less the gain per pound 
of feed. 
Since in all but one of the 67 droves, pork was produced as a 
by-product from the same feed, the gain in pork by-product as well 
as in beef is shown for the grain input, and the effect of the length 
of the feeding period and the weight of the (beef) animals upon the 
pork by-product is likewise shown. 
The accuracy with which these results measure the factors deter- 
mining the gains is shown by the fact that when the gain in weight 
