122
Sire Index for Milk Production in Cattle
TABLE V
Showing the calculation of the Intermediate Index for milk production of Sindhi Bull No. 56 from
Hosur Cattle Farm, Madras
No.
1
1
2
3
4
5
6
7
Total .
Average
Milk yield in lb.
Mothers
2
5103
3874
4339
4376
2878
3595
5241
24165
4027.5
Daughters
3
7824
4589
5136
10081
3268
5044
1256*
35942
5990.3
Days of lactation
Mothers
4
331
315
353
350
216
346
385
1911
318.5
Daughters
5
414
364
404
373
297
332
217
2184
364.0
Adjusted yields in lb.
Mothers
6
4780
3718
3788
3856
3752
3116
..
23010
3835.0
Daughters
7
4214
2562
1842
7769
3363
4031
..
23781
3963.5
Twice col.
7 minus
col. 6
8
3648
1406
— 104
11682
2974
4946
..
24552
4092
Square of
col. 8
9
13307904
1976836
10816
136469124
8844676
24462916
..
185072272
Remarks
10
*Sick
Correction Factor . . . . . . . . . . . .
Corrected sum of squares . . . . . . . . . .
Sampling Variance of Int. Index . . . . . . . . . .
Standard error of Int. Index . . . . . . . . . .
Standard Error × t 10 % . . . . . . . . . .
(24552) 2 /6
100466784
84605488
2820182.93
1679.3 lb.
2873 lb
Table VI gives a summary of the results re-
lating to all the three bulls. It shows the aver-
age total milk yield of dams and daughters, the
corresponding average lengths of lactation, the
adjusted yields and the values of the Interme-
diate. Index with their sampling errors.
It
shows at a glance the extent to which the
difference in milk yield between dams and dau-
ghters is affected by the difference in the ave-
rage lengths of their lactations. Thus, it will
be seen that the increased production of daugh-
ters of bull No. 8 and 56 is in a large degree due
to the extended length of lactation of daughters
and not wholly to the transmitting ability of
the bulls. The correct appraisal of the worth
of the bulls is obtained when the records are
adjusted to a standard length as shown in rows
8 and 9 of the table. The adjusted records
clearly show that bull No. 8 is not such a
transmitter as he appeared from the unadjusted
milk yield records; bull No. 56 has hardly made
any difference to the milk production of the
daughters, and bull No. 38 is worth more than
he looked from the unadjusted milk yield re-
cords. The correct value of the breeding worth
of the three sires is shown by the Intermediate
Index given in row No. 10.
TABLE VI
Showing the average total milk yields of mothers and
daughters, the corresponding average lengths of
lactation, the adjusted milk yields and values of
the Intermediate Index with the sampling errors
—
1 Number of pairs
2 Average total milk yield of
3 Average total milk yield of
daughters (lb.)
4 Average difference in total
milk yield (daughter minus
mother) (lb.)
5 Average length of lactation
of mothers (days)
6 Average length o f lactation
of daughters (days)
7 Average difference in length
of lactation (daughter minus
mother) (days)
8 Average total milk yield of
mothers adjusted to 300 days
9 Average total milk yield of
daughters adjusted to 300 days
(lb.)
Sindhi
Bull
No. 38
12
3718.6
4227.6
509.0
350.5
340.1
—10.4
2885.5
3572.2
Sindhi
Bull
No. 8
25
3660.0
4344.4
684.4
323.1
343.8
20.7
3260.6
3622.9
Sindhi
Bull
No. 56
6
4027.5
5990.3
1962.8
318.5
364.0
45.5
3835.0
3968.5