Ársrit Ræktunarfélags Norðurlands - 01.01.1971, Page 69

SUMMARY
The aim of the present study was to estimate the generation interval
in Iceland Sheep. The data were gathered from two sheep recording
associations for the period of 1942 to 1961. Information on the data
is given in table 1. The data was from 5 flocks in Sf. Thistill and frorn
18 flocks in Sf.Mýrahrepps sheep recording associations.
The generation interval was defined as the average age difference
between parents and offspring selected for breeding. The average
figures found were as follows: (years): Sire-son, 4,14, sire-daughter 3,
79, dam-son 4, 73 and dam-daughter 4, 89. Difference in the gener-
ation interval between the two sheep recording associations was found
in one case. The dam-son interval was 4, 30 years in Sf. Mýrahrepps,
and 5, 15 in Sf. Thistill. The results are given in table 2 and figures
1, 2 and 3.
The results are discussed from breeding point of view.
HEIMILDARRIT
(References)
Gjedrem, T. /96<S: Expected Frequency o£ Elite dams in different Age
Groups. Acta Agr. Scand., 18, 153—158.
Hallgrimsson, S. 1966: Innvirkning av noen faktorer pS fruktbarheten hos
sau. E'jölrit, Vollebekk 1966. 73 s.
Joakimsen, Ö. 1969: Generation Interval in Norwegian Sheep. Acta Agr.
Scand., 19, 175—177.
Johansson, I. 1949: Generationsintervallets liingd inom Svenska husdjurs-
raser. K. Lantbr. Akad. Tidskr., 88, 243-254.
Lush, J. L. 1945: Animal Breeding Plans. 443 pp. Ames Iowa State College
l’ress.
72