Íslenskar landbúnaðarrannsóknir - 01.03.1970, Page 36

34 ÍSLENZKAR LANDBÚNAÐARRANNSÓKNIR
No. 5, 20, 21, 22, 23, 24 and 25 were pre-
pared for analysis and punched.
On farm No. 4 the author had the op-
portunity to plan all matings involving
heterozygous white ewes as well as non-
white ewes before the mating season in
1960. The aim of the planning was to pro-
duce as many darkgrey lambs as possible
in the ílock in spring 1961. As these plan-
ned matings involved more than half the
number of ewes in the flock, all records
from 1961 were added to the previous col-
lection.
In 1960 the interest in obtaining homo-
zygous grey rams for breeding was appreci-
able, particularly in the neighboughood of
the farm Skeidháholt where the first ex-
periments on the production of homo-
zygous grey lambs were carried aut.
It was therefore decidecl to collect in-
formation from several farms in this area
on the use of rams which were either
known to be homozygous grey from the
genotype of their parents or assumed to
be homozygous grey on basis of their very
light grey colour. Included in this collec-
tion weie farm No. 2, Skeidháholt, both
the experimental animals and animals in
the private flock, and farms No. 3, 6, 7, 8,
9, 10, 11, 12, 13, 14, 15 and 16.
In the last mentioned 13 flocks, all in-
formation since 1953 was collected front
farm No. 3, wliile for the other private
flocks the data collection was restricted to
ewes which were mated to certain rams in
the year 1960/61, most of these rams being
lightgrey and assumed to be homozygous
grey. For the ewes mated to these rams all
available records from earlier record years
were also collected. As these ewes were
usually eitlier nonwhite or heterzygous
white, and as they had previously been
mated to rams with a variety of colours,
these data contained a lot of information
with respect to colour inheritance. As the
prices of darkgrey lambskins at this time
were cjuite high, it was f'elt that almost
all ewes on these farms which could pro-
duce grey lambs would have been mated
to the lightgrey rams. This method of col-
lection was therefore expected to extract a
very high proportion of the available in-
formation about colour inheritance from
the records on these farms.
In addition to the farms already men-
tioned in this chapter, the data on the 2
rams tested on farms No. 17 and 18 de-
scribed on p. 28 were also included in this
collection. Data were also obtained from
one additional farrn, No. 19, but when
they liad been inspected and the people in
charge of the recording interviewed, it was
felt that all records from this farm should
be discarded, as several serious inconsi-
stencies between date of mating and date
of lambing were found with resulting in-
consistencies in the expected colours. On
all the other farms, all collected records
were included in the study.
Special forms for the collection of the
information from the last mentioned 17
farms were printed, and as the completed
forms came in they were prepared for ana-
lysis and the data punched on cards. These
cards were checked mechanically in a card
verifier, and faulty cards replaced by cor-
rected cards.
The punching of the data in the present
study was completed in 1963, but circurn-
stances prevented an analysis of the records
at that time, so the cards were stored until
the opportunity of analysing them at the
Department of Statistics of the University
of Edinburgh presented itself.
B. ITEMS OF INFORMATION
COLLECTED
The amount of information obtained on
each animal in the data collection varied
somewhat depending on its source.
Most complete information was avail-