GENETICS: W. E. CASTLE 
431 
an average of 4617 pounds of milk. The recorded butter-fat tests of 
these cows are too few to form an adequate basis for estimates of their 
individual butter-fat production. But such tests as were made agree 
sufficiently well with Roberts' estimate of 5.0% for the breed. On this 
TABLE 2 
Milk and Butter-Fat Production of Pure-Bred Registered Holstein Cows 
H. S. Clotilde 
H. S. Inka 
H. Perfecta Clotilde. . . 
H. S. Judy Colantha. 
H. S. Katharine 
H. S. Pietertje 
H. S. Twisk 
H. S. Wachusett 
H.M. Cre. DeKol... 
H. S. Erie Colantha . . 
H. S. Erie Vernon . . , 
H. S. V. Julipana .... 
H. S. Landor 
H. M. Segis 
H. S. Vale Judy 
H. S. Veldoor 
H. Cre. Mercedes 
DeKol 
H. M. Judy Colantha 
H. L. Whetstone 
DeKol 
H. A. Cre. DeKol... . 
H.I. Colantha DeKol. 
H. Tessa Netherland . 
H. C. Plum 
H. S. Dexter Erie.... 
H. Judy Cre. DeKol. . 
Average 
FIRST LACTATION PERIOD 
Age 
3 
3i 
3i 
2f 
2h 
2i 
2h 
2f 
21 
31 
2H 
2t 
3 
Si 
21 
2H 
3 
2h 
21 
21 
2.825 
Time 
months 
9 
10 
11.0 
Total 
pounds of 
milk 
7,765 
9,089 
(8,030) 
8,875 
8,247 
(6,887) 
(7,701) 
(6,481) 
(5,432) 
6,417 
8,582 
7,725 
(8,900) 
10,101 
(7,445) 
(8,928) 
5,493 
(5,230) 
7,479 
7,692 
9,699 
8,628 
7,945 
(7,399) 
7,673 
Fat 
per 
cent 
3.5 
3.4 
3.2 
3.6 
3.2 
3.2 
3.4 
3.6 
3.4 
Total 
fat 
271 
309 
257 
319 
264 
220 
261 
233 
Av. 267 
261 
SECOND LACTATION PERIOD 
Age 
^ 
3f 
31 
31 
31 
31 
4i 
4.0 
Time 
months 
101 
8 
11 
11 
10 
9 
11 
10 
9 
' 2 
m 
Total 
pounds of 
milk 
(9,803) 
(8,866) 
(10,025) 
(9,455) 
(9,263) 
(8,631) 
10,312 
10,813 
(7,619) 
10,470 
10,248 
10,327 
(9,555) 
(8,186) 
(6,170) 
(8,961) 
(7,490) 
(9,190) 
11,989 
(12,041) 
9,475 
Total 
fat 
343 
301 
320 
340 
296 
276 
350 
392 
Av.127 
322 
basis the average butter-fat production of the 8 Guernseys in their first 
lactation period would be 231 pounds. 
Table 1 shows the observed milk and estimated butter-fat production 
of 31 Fi cows which calved at the average age of 2.6 years, one-tenth of 
a year younger than the Guernseys, two-tenths of a year younger than 
the Holsteins. They produced an average of 6612 pounds of milk. 
