4 BULLET IX 1069, U. S. DEPARTMENT OF AGRICULTURE. 
tainecl show about the same averages as they would if 12-months 
records only were used. The cows discarded before the end of the 
testing year were inferior cows, which would tend to lower average 
production, but they generally were on test during the early part 
of their lactation period, which would tend to increase average pro- 
duction. The figures shown in Table 1 indicate that these two in- 
fluences nearly offset each other when large numbers of records are 
used. 
This bulletin considers feeds chiefly from the standpoint of the in- 
come they produce over their cost but a study is now being made of 
the cow-testing-association records to determine the relation of feeds 
to other factors, in which feeds of various kinds are considered by 
quantity and feeding value. 
GENERAL AVERAGES OF PRODUCTION, FEED COST, AND 
INCOME. 
The figures in Table 1 are from the records of 120 sets of cow-test- 
ing-association records and they compare the 12-month records 
with all the records furnished by those associations. Tables 1 and 
5 are the only tables in which anything but 12-month records are 
used. 
Table 1. — Comparison of the 12-month records with all the records studied — 
Averages per cow-year; period 1910 to 1920, inclusive. 
Item. 
Cows on 
test 12 
months 
and 
whose 
breed 
and age 
were 
given. 
Cows on 
test 4 
months 
and not 
more 
than 12 
(includes 
first 
column). 
Item. 
Cows on 
test 12 
months 
and 
whose 
breed 
and age 
were 
given. 
Cows on 
test 4 
months 
and not 
more 
than 12 
(includes 
first 
column). 
21,234 
21.234 
6, 077 
4.08 
248 
SO. 48 
S11S. 00 
41,990 
37. 362 
5.9S9 
4.12 
247 
$0.46 
S112. 39 
Cost of roughage 
$33.41 
$21. 89 
$55.30 
$62.70 
$2,13 
$32.03 
Cost of grain 
$21. 03 
Average milk yield, pounds... 
Butterfat t est "per cent 
Average butterfat, pounds 
$53.06 
Income over feed, cost 
$59.33 
Returns for §1 expended for 
feed 
$2.11 
Value of product 
1 A cow-year may be the record of 1 cow on test 12 months, or it may be made up of the records of 2 or 
more cows'the sum of whose testing periods equals 12 months. 
The average milk production per cow-year for the cows on test 12 
months was 6,077 pounds, while the average milk production for all 
the cows on test was 5,989 pounds, a difference of only 88 pounds. 
The average production of butterfat per cow-year was 248 pounds 
for the cows on test 12 months and 247 pounds for all the cows on 
test, a difference of only 1 pound. In return for $1 expended for 
feed there was a difference of only 2 cents per cow-year. For the 
cows on test 12 months the returns averaged $2.13 and for all the 
cows on test the returns averaged $2.11. 
