Íslenskar landbúnaðarrannsóknir - 01.03.1970, Side 86

84 ÍSLENZKAR LANDBÚNAÐARRANNSÓKNIR
TABLE 44
Maximum likelihood estimates of the parameters u, v and s
and their standard errors
Parameter
Matings in table 39 B
Singlcs Twins
1. u and v estimated for both singles and tunns
•0.051 :
0.004 :
0.111
0.053
2. u and v estimated only for twins
0.177 ± 0.104
0.199* ± 0.104
0.285** ± 0.076
0.100** ± 0.038
0.293** ± 0.074
0.099** ± 0.037
*) P < 0.05
**) P<0.01
TABLE 45
Reduction in values due to the maximum likelihood parameters in Table 44
Source of y/- Matings in table 39 B
DF X2 I’robability
Total 24 38.484 0.05 > P > 0.02
us, uT, VS, vT, s 5 18.105 P<0.01
Remainder .... 19 20.359 0.50 > P > 0.30
uT. vT. s 3 17.723 P< 0.001
Remainder .... 21 20.741 0.50 > P > 0.30
us, vg (by diff.) 2 0.382 0.90 >P> 0.80
average ovulation time or variation in
ovulation time. No such difference has
been demonstrated in sheep as far as can
be seen, but it is of interest in this connec-
tion that a large difference has been found
between Large White pigs and an isolated
sample of Large Black pigs with respect
to time of ovulation, the Large Black
ovulating 24 hours later relative to onset
of oestrus, than the Large White (Burger,
1952, quoted by Hancock, 1962).
The difference between the matings in
table 39 B and 39 C as regards the varia-
tion in segregation ratios is of considerable
interest in connection with selective fer-
tilization and embryonic mortality. The
fact that the variation in table 39 C is
mainly found among singles while the