42 DEPARTMENT BULLETIN 1492, IT. S. DEPT. OF AGRICULTURE 
tal feeding. In the case of the- Iberia farm lot, the basal feed was 
brewers' rice. Such variations in initial firmness as here shown are 
considered as contributing factors to the divergent final results be- 
tween the various lots. 
The wide range of minimum and maximum gains within certain 
lots probably also contributed to the wideness of the distribution of 
grades. This is particularly noticeable in the Arkansas station ex- 
periment of 1925. The one experiment (Iberia, 1924) in which all 
hogs were graded the same shows a relatively narrow range in gains. 
It was stated in Department Bulletin 1407 (4) that after passing a 
certain weight or degree of finish there is a tendency for hogs fed 
rice polish to acquire gradually a lower degree of softness. The 
maximum softness for hogs begun at approximately TO pounds is 
reached with a gain of about 40 pounds. It therefore appears that 
at the close of the rice-polish period the Arkansas station lot of 
1926 was softer than the Iberia, 1924, lot which had begun to harden 
at the time the feed was changed. This fact, together with the 
initial firmness, materially aided the development of firmness in the 
Iberia hogs, even though the gain ratio (1:1.45) was relatively nar- 
row. The rice polish used in the Coastal Plain station experiment 
had a fat content of 15.8 per cent as compared with values ranging 
from 12.4 to 14 per cent in the other experiments. This high fat 
content probably developed a softer carcass during the softening 
period than in the Arkansas. 1925, and Iberia, 1926, lots even though 
the gains were comparable. The average gain on hardening feed was 
only 1.55 times that on softening feed, so as a result the Coastal 
Plain lot was the softest of all lots at slaughter. 
Considering that factors of initial firmness, gains, and gain ratios 
are generally in line with the usual grade averages and refractive- 
index values, it appears that the gradings on the Mississippi, 1924, 
and Iberia, 1924, lots were somewhat firmer than justified. These two 
lots were graded at the same time, and it is entirely possible that 
some unknown factor was responsible for this seemingly abnormal 
grading. 
The general average on the total of 75 hogs shows that the aver- 
age gain during the rice-polish period was 51.87 pounds and during 
the corn period was 92.70 pounds, which is a ratio of 1 : 1.79. The 
periods were of approximately equal length, namely, eight weeks. 
The refractive index average on the back fat was 1.4599. which is 
within the medium-soft grade limits for hogs fed rice polish. The 
grading shows that 53 out of 75 were graded medium soft or soft. 
The variations between lots were such as largely to compensate each 
other in the averaging of results on all hogs. One factor which 
possibly should not be overlooked in the application of these results 
to practical feeding practice is the range in fat content of rice polish. 
The average fat content of this feed, as given by the Bureau of Chem- 
istry, is 9.7 per cent as compared to 9.1 per cent by Henry and Morri- 
son (5). These figures are decidedly lower than for any of the rice 
polish used in the present investigations. When rice polish of low 
oil content is used it is probable that less softening will develop. 
These results have been summarized in the following conclu- 
sion (7): 
