BUTTERFAT PRODUCTION OF CATTLE 
17 
Table 20. — Comparison of average initial and retest records of Jerseys having 
initial records made at ages of 9 and 10 years (class A and class A A records) 
Number 
Average initial 
butterfat record 
made at 9 to 9H 
years old 
Average reentry records made at ages 
shown in these columns by same cows 
as initial records shown in column at 
left (pounds of butterfat) 
Increase 
due to 
age 
Portion of 
reentry record 
Average 
due to 
develop- 
ment for 
this group 
of cows 
© 
o 
o 
o 
o 
o 
O 
o 
o 
o 
<*> 
o 
due to devel- 
opment 
7 
Pounds 
450 
480 
407 
471 
516 
Pounds 

-15 
-13 
-15 
-21 
-16 
-12 
-16 
-16 
-16 
-13 
-12 
-14 


-45 
Pounds 
66 
192 
31 
-74 
110 
60 
22 
—75 
24 
15 
12 
120 
36 
-57 
-23 
78 
P.ct. 
12.8 
29.2 
7.3 
-19.4 
14.8 
11.1 
5.6 
-18.6 
4.8 
3.1 
2.8 
24.0 
8.0 
-12.4 
-4.8 
Per cent 
3 
657 
1 
1 
425 
> 13.8 
1 
382 
j 
741 
Made at 9}4 to 10 
years old 
2 
652 
495 
385 
495 
495 
1 
1 
539 
1 
395 
> 5.4 
1 
404 
1 
503 
) 
483 
Made at 10 to 10^2 
years old 
7 
434 
426 
392 
430 
1 
1 
425 
2 
1 
500 
7.4 
2 
I 
452 
J 
461 
Made at 10H to 11 
years old 
3 
518 
501 
573 
1 
1 
478 
^ -5.8 
1 
606 
12. 9il 
