172
Breeding Experiment with Goats
We shall now consider the results of the compa-
rison of the second progeny with their mothers in
the first progeny. These are given in Table X.
Unlike Table VI, where a collective comparison
over all lactations has been made owing to lack of
information regarding the order of lactations of the
foundation stock, the comparison in this table is
made for corresponding lactations. It will be
seen that far from showing an improvement the
results indicate significant deterioration in all the
lactations. The material is too scanty to allow
examination of seasonal effect in the way we did
in Tables VIII and IX. While season may have
had an effect one way or the other, the data
leave little doubt in our mind that the bucks had
little worth as transmitters of milk yield.
TABLE X
Comparison between the performance of the second progeny and their dams
First lactation .
Second lactation .
Third lactation .
1st progeny
Average . . .
Standard error. . .
2nd progeny
Average .
.
.
.
Standard error. . . .
t
1st progeny
Average . . .
Standard error . .
2nd progeny
Average . . . .
Standard error . . .
t
1st progeny
Average . . .
Standard error . . .
2nd progeny
Average .
.
.
.
Standard error . . .
t
Number
of
goats
18
27
15
15
7
7
Total
milk
yield
oz.
5396.3
423.6
4864.1
349.7
0.9
5558.4
131.4
5216.0
102.5
0.6
7906.3
1416.6
5617.4
931.3
1.4
Number
of days
in milk
167.8
11.9
176.9
11.9
1.7
152.6
8.8
192.0
9.8
3.0**
206.0
28.2
215.7
29.6
0.2
Average
milk
yield per
day
oz.
32.2
1.1
27.5
0.9
3.2**
36.4
1.4
27.2
1.4
4.8**
38.4
2.1
26.0
2.2
4.1**
Number
of
goats
18
25
11
12
Kidding
interval
264.3
23.1
313.7
23.7
1.4
257.1
22.5
0.0
3328.7
1.9
Average
milk
yield per
day of
kidding
interval
oz.
20.5
1.2
14.8
1.2
3.6**
23.6
1.3
15.7
1.5
3.8**
Sufficient data not
available
Table XI shows the results of the progeny tests
for bucks Nos. 152M and 633M having more than
five daughters. As little reliance can be placed on
the progeny tests involving less than five compa-
risons, these are not made. It will be seen that the
progeny of 152M does not show a significantly
different performance from that of their mothers
but that the progeny of 633M suggests a significant
deterioration. The comparison of the relative
worths of the two sires, however, made in the last
row of the table does not suggest that 633M was a
distinctly inferior buck to 152M.
The results of the comparison of the third pro-
geny with their dams in the second progeny are
given in Table XII. It will be seen that while
there is some increase in the total milk yield, there
is a significant reduction in the average milk yield
per day of lactation and a considerable though
non-significant reduction in the average milk yield
per day of kidding interval. This corroborates to
a great extent the findings of Table X.
The comparisons so far made are those between
the successive progenies and their mothers, and
although appropriate from the view-point of test-
ing the success of breeding policy do not give us a
complete picture of the improvement in the perfor-
mance of the herd as a whole in successive genera-
tions. This is done in Tables XIIIA and XIIIB,
which give the performance over all lactations of
the foundation stock, of the first progeny and lacta-
tionwise performance of the first, second and third
progenies. It will be seen that while the first pro-
geny shows a better performance over the founda-
tion stock, there is a steady deterioration in the per-
formance thereafter.