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Direct and maternal (co)variance components and heritability estimates for body weights in Chokla sheep

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Title Direct and maternal (co)variance components and heritability estimates for body weights in Chokla sheep
Not Available
 
Creator B P Kushwaha
A Mandal
A L Arora
R Kumar
S Kumar
D R Notter
 
Subject body weights; Chokla sheep; (co)variance estimates; maternal effects
 
Description Not Available
Estimates of (co)variance components were obtained for weights at
birth, weaning and 6, 9 and 12 months of age in Chokla sheep maintained
at the Central Sheep and Wool Research Institute, Avikanagar,
Rajasthan, India, over a period of 21 years (1980–2000). Records of
2030 lambs descended from 150 rams and 616 ewes were used in the
study. Analyses were carried out by restricted maximum likelihood
(REML) fitting an animal model and ignoring or including maternal
genetic or permanent environmental effects. Six different animal models
were fitted for all traits. The best model was chosen after testing the
improvement of the log-likelihood values. Direct heritability estimates
were inflated substantially for all traits when maternal effects were
ignored. Heritability estimates for weight at birth, weaning and 6, 9 and
12 months of age were 0.20, 0.18, 0.16, 0.22 and 0.23, respectively in
the best models. Additive maternal and maternal permanent environmental
effects were both significant at birth, accounting for 9% and
12% of phenotypic variance, respectively, but the source of maternal
effects (additive versus permanent environmental) at later ages could
not be clearly identified. The estimated repeatabilities across years of
ewe effects on lamb body weights were 0.26, 0.14, 0.12, 0.13, and 0.15
at birth, weaning, 6, 9 and 12 months of age, respectively. These results
indicate that modest rates of genetic progress are possible for all
weights.
Not Available
 
Date 2018-11-20T04:18:03Z
2018-11-20T04:18:03Z
2009-01-01
 
Type Research Paper
 
Identifier Not Available
0931-2668
http://krishi.icar.gov.in/jspui/handle/123456789/12173
 
Language English
 
Relation Not Available;
 
Publisher Blackwell Verlag GmbH