CORN" AND HOG CORRELATIONS 
51 
SLAUGHTER AND LIVE WEIGHT 
The western summer and winter slaughter and summer and winter 
live weight can be represented as determined by the amount of breed- 
ing and the size of the corn crop in the same and preceding years, 
with a reasonable degree of success. The path coefficients which have 
been found by repeated trials to give the closest approximation to 
the observed correlations are given in Table 11, primes being used as 
before to indicate preceding years. 
Table 11. — The path coefficients which measure the influence of variations in hog 
breeding and the corn crop in a period of three or four years on the variations in 
summer and winter live weight and summer and winter hog pack in a given year 
Factor 
Summer \ Winter 
weight ; weight 
Summer Winter 
pack j pack 
Breeding _ 
+0.80 +0.35 
+0.30 
-0.10 
+0.45 
+0.35 
+0.35 
+0.85 
-0.15 
+0.35 
Breeding"' 
+0.15 
Corn crop ... .- 
+0.65 
-0.25 
-0.20 
+0.55 
-0.10 
! 
The use of corn crop in the present connection instead of corn 
price, used in connection with breeding and hog costs, is somewhat 
arbitrary. The fact, however, that crop shows at least as high maxi- 
mum correlations with weight and pack as does price, indicates that 
the influence of corn on these hog variables is not exclusively through 
the mediation of price. It is not practicable to attempt to dis- 
tinguish the direct influence of the crop from the indirect effect 
through price. The use of crop here serves to balance the greater 
influence attributed to price in the central system. 
Summer weight has been used as an indicator of the amount of 
breeding during the year. The coefficient for the influence from the 
breeding of the current year is accordingly high ( + 0.80) . It is neces- 
sary to assume, however, that there is considerable influence from the 
preceding year ( + 0.30). The way in which heavy breeding in the 
preceding fall as well as in the spring and fall of the current year 
increases live weight by increasing the percentage of old sow T s slaugh- 
tered has been discussed previously. The negative coefficient for the 
path from the breeding of the second preceding year ( — 0.15) measures 
the effect of an excess of hogs in reducing the feed available per head. 
For a similar reason one might expect a positive influence of the pre- 
ceding and perhaps also current corn crop. The coefficient for such 
an effect can be of only very small importance, however, in view of the 
low correlations between crop and summer weight. 
Summer weight is an even better indicator of current breeding than 
is brought out by the path coefficient of +0.80. The correlation 
resulting from the three factors above is +0.91. Summer weight is 
determined 92 per cent by these factors. 
It was concluded in an earlier section that winter weight is deter- 
mined primarily by the supply of corn and secondarily by the number 
of old sows slaughtered as the result of the breeding of the preceding 
spring. In harmony with these conclusions the most satisfactory 
approximations to the correlations involving winter weight w r ere 
