Estimation of genetic parameters for lamb weight at various ages in Mehraban sheep
The aim of the present study was to estimate variance components and genetic parameters among growth traits of Iranian Mehraban sheep using single and two-trait animal models. Analyzed traits included, birth weight (BW), weaning weight (WW), weight at 6 months (W6), weight at 9 months (W9) and yearl...
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| Format: | Article |
| Language: | English |
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Taylor & Francis Group
2010-01-01
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| Series: | Italian Journal of Animal Science |
| Subjects: | |
| Online Access: | http://www.aspajournal.it/index.php/ijas/article/view/45 |
| _version_ | 1818976755784876032 |
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| author | Ahmad Hassanabadi Moradpasha Eskandarinasab Farhad Ghafouri Kesbi |
| author_facet | Ahmad Hassanabadi Moradpasha Eskandarinasab Farhad Ghafouri Kesbi |
| author_sort | Ahmad Hassanabadi |
| collection | DOAJ |
| description | The aim of the present study was to estimate variance components and genetic parameters among growth traits of Iranian Mehraban sheep using single and two-trait animal models. Analyzed traits included, birth weight (BW), weaning weight (WW), weight at 6 months (W6), weight at 9 months (W9) and yearling weight (YW). (Co)variance components were estimated with REML for an animal model that included fixed effects of year, season, age of dam, sex and type of birth. Random effects included direct and maternal additive genetic effects, maternal permanent environmental effects with a direct-maternal genetic covariance and random residual effects. Direct heritability (h2) was increased from 0.19 at birth to 0.36 at yearling age. Inversely, maternal heritability (m2) estimates were decreased from 0.11 at birth to 0.01 at yearling age. Estimates of maternal permanent environmental variance as a proportion of phenotypic variance (c2) were 0.06 and 0.04 for BW and WW, respectively and they were very negligible for other traits. Direct-maternal genetic correlation (ram) was positive and it increased with age from 0.05 for BW to 0.73 for YW. For the two–trait analyses, the genetic correlations were larger among WW, W6, and W9 (0.59 to 0.82) and were small between BW, W9, and YW (<0.4). Positive genetic correlations between traits show that selection at any age is possible. |
| first_indexed | 2024-12-20T16:16:54Z |
| format | Article |
| id | doaj.art-ced6d3d142494bbbad1c72d6630d5dc0 |
| institution | Directory Open Access Journal |
| issn | 1594-4077 1828-051X |
| language | English |
| last_indexed | 2024-12-20T16:16:54Z |
| publishDate | 2010-01-01 |
| publisher | Taylor & Francis Group |
| record_format | Article |
| series | Italian Journal of Animal Science |
| spelling | doaj.art-ced6d3d142494bbbad1c72d6630d5dc02022-12-21T19:33:46ZengTaylor & Francis GroupItalian Journal of Animal Science1594-40771828-051X2010-01-01719510410.4081/ijas.2008.95Estimation of genetic parameters for lamb weight at various ages in Mehraban sheepAhmad HassanabadiMoradpasha EskandarinasabFarhad Ghafouri KesbiThe aim of the present study was to estimate variance components and genetic parameters among growth traits of Iranian Mehraban sheep using single and two-trait animal models. Analyzed traits included, birth weight (BW), weaning weight (WW), weight at 6 months (W6), weight at 9 months (W9) and yearling weight (YW). (Co)variance components were estimated with REML for an animal model that included fixed effects of year, season, age of dam, sex and type of birth. Random effects included direct and maternal additive genetic effects, maternal permanent environmental effects with a direct-maternal genetic covariance and random residual effects. Direct heritability (h2) was increased from 0.19 at birth to 0.36 at yearling age. Inversely, maternal heritability (m2) estimates were decreased from 0.11 at birth to 0.01 at yearling age. Estimates of maternal permanent environmental variance as a proportion of phenotypic variance (c2) were 0.06 and 0.04 for BW and WW, respectively and they were very negligible for other traits. Direct-maternal genetic correlation (ram) was positive and it increased with age from 0.05 for BW to 0.73 for YW. For the two–trait analyses, the genetic correlations were larger among WW, W6, and W9 (0.59 to 0.82) and were small between BW, W9, and YW (<0.4). Positive genetic correlations between traits show that selection at any age is possible.http://www.aspajournal.it/index.php/ijas/article/view/45Body weight, Growth, Mehraban sheep, (Co)variance components, Heritability. |
| spellingShingle | Ahmad Hassanabadi Moradpasha Eskandarinasab Farhad Ghafouri Kesbi Estimation of genetic parameters for lamb weight at various ages in Mehraban sheep Italian Journal of Animal Science Body weight, Growth, Mehraban sheep, (Co)variance components, Heritability. |
| title | Estimation of genetic parameters for lamb weight at various ages in Mehraban sheep |
| title_full | Estimation of genetic parameters for lamb weight at various ages in Mehraban sheep |
| title_fullStr | Estimation of genetic parameters for lamb weight at various ages in Mehraban sheep |
| title_full_unstemmed | Estimation of genetic parameters for lamb weight at various ages in Mehraban sheep |
| title_short | Estimation of genetic parameters for lamb weight at various ages in Mehraban sheep |
| title_sort | estimation of genetic parameters for lamb weight at various ages in mehraban sheep |
| topic | Body weight, Growth, Mehraban sheep, (Co)variance components, Heritability. |
| url | http://www.aspajournal.it/index.php/ijas/article/view/45 |
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