4 BULLETIN 1069, U. S. DEPARTMENT OF AGRICULTURE. 
tamed show about the same averages as they would if 1'2-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. 
Cows on 
Cows on 
Cows on 
Cows on 
test 12 
test 4 
test 12 
test! 
months 
months 
months 
months 
and 
and not 
and 
and not 
Item. 
whose 
more 
Item. 
whose 
more 
breed 
than 12 
breed 
than 12 
and age 
(includes 
and age 
(includes 
were 
first 
were 
first 
given. 
column). 
given. 
column). 
21,234 
21.234 
41,990 
37, 362 
Cost of roughage 
Cost of gram 
$33. 41 
$21. ^9 
$32.03 
Number of cow-years > 
S21. 03 
Average milk yield, pounds... 
Butterfat test. 'per cent 
6,077 
5. 9>9 
Total feed cost 
$55. 30 
$53.06 
4.08 
4.12 
Income over feed cost 
-$62. 70 
$59.33 
Average butterfat, pounds 
248 
2-17 
Returns for SI expended for 
Price of butterfat 
SO. 48 
SO. 46 
feed 
$2. 13 
S2. 11 
Value of product 
J118.00 
$112. 39 
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 S2.ll. 
