BUTTERFAT PRODUCTION OF CATTLE 
11 
Table 12. — Comparison of average initial and retest records of Guernseys having 
initial records made at age of 9 years or older {single-letter records) 
Num- 
Average initial butter- 
fat 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) 
In- 
crease 
due to 
age 
Portion of re- 
entry record 
due to 
development 
Average 
due to 
develop- 
ment for 
this 
group 
cows 
11 
to 
11^ 
to 
12 
12 
to 
12H 
to 
13 
13 
to 
13H 
14H 
to 
15 
1 
Pounds 
494 
581 
488 
Pounds 
-24 
-28 
-21 
-29 
-19 



Pounds 
18 
34 
68 
41 
133 
97 
83 
104 
p. a 
3.7 
5.8 
14.1 
6.7 
26.3 
18.3 
16.8 
14.6 
Per cent 
} 4.8 
1 
587 
481 
Made at 9>2 to 10 years 
old 
1 
434 
601 
j- 10.4 
1 
613 
506 
Made at 10 to 10H years 
old 
1 
392 
26.3 
530 
Made at 11 to 11H years 
old 
1 
433 
18.3 
493 
713 
Made at 12 to 12H years 
old 
1 
410 
16.8 
Made at 13H to 14 years 
old 
1 
609 
14,6 
Table 13. — Comparison of average initial and retest records of Jerseys having 
initial records made at age less than 2 years (class A and class A A records) 
Num- 
Average 
initial 
butterfat 
record 
made 
under 2 
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) 
In- 
crease 
due to 
age 
Portion of 
reentry record 
due to de- 
velopment 
Average 
due to 
develop- 
ment for 
this 
group 
ber of 
cows 
eo 
o 
to 
o 
o 
o 
-*< 
>n 
o 
-if 
© 
CO 
o 
5 
o 
o 
i 
«0 
s 
o 
00 
o 
QO 
o 
00 
OS 
o 
o 
51 
Pounds 
340 
357 
342 
343 
358 
359 
365 
354 
387 
365 
369 
336 
330 
310 
328 
412 
Pounds 
43 
64 
80 
97 
116 
119 
134 
133 
145 
137 
139 
126 
124 
117 
123 
Pounds 
29 
31 
58 
68 
51 
67 
75 
64 
16 
105 
63 
253 
331 
77 
211 
Per cent 
7.0 
6.9 
12.1 
13.4 
9.7 
12.3 
13.1 
11.6 
2.9 
17.3 
11.0 
35.4 
42.2 
15.3 
31.9 
Per cent 
127 
45? 
40 
480 
71 
508 
36 
525 
28 
.545 
25 
574 
16 
551 
\ 10.2 
11 
548 
7 
607 
8 
571 
3 
715 
1 
785 
504 
662 
2 
2 
