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PRINT: ISSN 2221-1896
ONLINE : ISSN 2223-0343
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Estimation of genetic parameters
for
udder type traits in the first lactation of Iranian
dairy Holstein cattle |
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Abbas Mikhchi1,
Mojtaba Hosseinpour Mashhadi2 and
Ghobad Asgari Jafarabadi3
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1Department
of
Animal Science, Science and Research Branch,
Islamic Azad University, Tehran, Iran; 2Department of Animal
Science, Mashhad Branch, Islamic Azad University, Mashhad, Iran; 3Department
of Animal Science, Varamin-Pishva Branch, Islamic Azad University,
Varamin, Tehran, Iran
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Abstract |
The objective of this study
was
to estimate genetic parameters
of
8
udder
type traits in the first lactation of Holstein
dairy cows. The data set consisted of records of 2325
Holstein
cows from
1998 to 2011.
This data was obtained from Agricultural-Jihad Organization in Khorasan Razavi Province
(Northeast of Iran).
Traits, all scored on 1 to 9 point scale, were fore udder attachment,
udder depth, suspensory ligament, teat length, front teat placement,
rear teat position.Genetic parameters were estimated using univariate
and bivariate analysis by Wombat software. The models included fixed
effects of herd, year, season of calving and the random effect of
animal. Heritability estimates obtained from univariate analysis were
similar to those obtained from bivariate analysis. Heritability ranged
from (0.03) to (0.32) for
suspensory ligament
and
udder depth respectively. Genetic correlations among the udder type
traits ranged from (-0.54) to (0.99) for (udder depth and teat length)
and (suspensory ligament and udder depth) respectively. Corresponding
phenotypic correlations for most pairs of traits were similar in
direction but smaller in magnitude than the genetic correlations.
Estimated parameters for udder type traits will be used to update the
selection index of Holstein
dairy cattle.
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Keywords:
Genetic correlations,
Heritability,
Iranian Holstein dairy cattle,
Udder type traits |
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To cite this article:
A Mikhchi,
MH Mashhadi
and
GA Jafarabadi,
2013.
Estimation of genetic parameters
for
udder
type traits in the first lactation of Iranian
dairy Holstein
cattle.
Res.
Opin. Anim. Vet. Sci., 3(12), 457-461. |
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