K. MAIJALA

U. LINDSTRÖM

English

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DEVELOPMENT OF THE COEFFICIENT OF INBREEDING AND
RELATIONSHIP IN THE FINNISH AYRSHIRE BREED.
U. LINDSTRÖM K. MAIJALA. f)epartment nJ Animal Breeding,
Agriri<ltural Research Centre, Tikllurila, Finland.
On the basis of samples of cows taken from the herd hook (4-lines pedigrees carried back
to 1894-97) and on pedigree information (7 generations) for AI bulls the level of inbreeding and
relationship in the Finnish Ayrshire breed was studied. By year of birth, samples of 50 cows
were taken for each of the years 1915, -- 25, - 35, - 45, - 55 and &mdash; 60 as well as a sample
of 100 cows for the year 1965. The 783 AI bulls analysed were born between 1939 and 1962.
The coefficient of relationship rose from 2.0 ! 0.5 per cent in 1915 to 7.3 ! 0.6 per cent in
1965 and has, in the period 1945-65, remained at the same level. Over the whole period studied
the coeflicient rose, on an average, 0.77 per cent /generation, i. e. O.là1 per cent /year.
The coefficient of inbreeding (F!) rose from 1.2 _I- 0.4 per cent in 1915 to 3.2 1 0.4 per cent
in 1965. Up to 1935 the observed coefficients were in agreement with those expected on the
basis of the degree of relationship. In the following 20 years period the observed Fx values
were some 2 per cent units lower than the expected ones. Over the whole period studied the
coefficient rose, on an average, 0.34 per cent /generation, i. e. 0.05 per cent /year.
The Scottish ancestors’ proportion of the genes increased from 65 per cent in 1915 to 92 per
cent in 1965. On an average the earlier importations accounted for 59-72 per cent of the genes.
Those imported in 1923 have since 1935 accounted for at least 1 /5 of the genes. The Agrshire
animals imported from Sweden accounted for 14-17 per cent of the genes in 1915-35, but only
for 4,5-5,0 per cent in 1955-65. Ancestors of native or unknown origin accounted for over 21
per cent of the genes in 1915, but only for 3-8 per cent in 1945-65.
The relationship of the AI bulls to 7 prominent ancestors varied, on an average, between
2.4 and 12.6 per cent. There was a slight tendency for the degree of relationship to decrease
with decreasing age of the bull categories.
The mean F for AI bulls born in 1939-44, 1945-49, 1950-54, 1955-59 and 1960-62 were
2.1, 4.1, 3.3, 2.4 and 2.3 per cent, respectively. Thus there was no significant trend in the deve-
lopment. Only 28 bulls (3.6 %) had an Fj of 9 per cent or more, over 90 per cent had less than
6 per cent.
The bull South Craib Snowball A 3399 (imported in 1923 from Scotland) was the individual
influencing the breed mostly. His direct relationship to the cows increased from 1 per cent in
1925 to 14.8 per cent in 1965. His relationship to the AI bulls in use in 1955 was 16.4 per cent
and to those in use in 1960 12.4 per cent.
GEWINNFUNKTIONEN &mdash; EIN HILFSMITTEL FÜR DIE PLANUNG VON
GEBRAUCHSKREUZUNGEN BEIM SCHWEIN
F. FEWSON. Institut für Tievzüchtung und Tievhaltung der Llnivevsitat
Hohenheim - BRD.
V. JAKUBEC. 7’’O!C/!MK!:K.’!<!<M< für Tierzucht in Uhyineves bei Pva&bet ; - CSSR
Aufbauend auf den Arbeiten von S!IITH (1964), MOAV und Mowv (1966, Breed. Poult. Sei.,
7, 5) sowie MoAv (1966, Anim. Prod., 8, 193, 203, 365) wurden Gewinnfunktionen für die Rein-
zucht und Gebrauchskreuzung beim Schwein entwickelt. In der allgemeinen Gewinnfunktion
für die Schweineproduktion wird mit einer variablen Erlöskomponente /Qualitäts-bzw.-abs-
chläge /gerechnet, in die verschiedene Merkmale der Schlachtkörperqualität eingehen können.


DEVELOPMENT OF THE COEFFICIENT OF INBREEDING AND RELATIONSHIP IN THE FINNISH AYRSHIRE BREED

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DEVELOPMENT OF THE COEFFICIENT OF INBREEDING AND RELATIONSHIP IN THE FINNISH AYRSHIRE BREED

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