Definition of subgroups for fixed regression in the test-day animal model for milk production ofHolsteincattle in theCzech Republic
The investigation was based on roughly 3.9, 2.7 and 1.7 million test-day records from first, second and third lactation, respectively, sampled from 596 200 Czech Holstein cows between the years 1991 and 2002. Breeding values were estimated from multi-lactation random-regression test-day models which...
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| Format: | Article |
| Language: | English |
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Czech Academy of Agricultural Sciences
2005-01-01
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| Series: | Czech Journal of Animal Science |
| Subjects: | |
| Online Access: | https://cjas.agriculturejournals.cz/artkey/cjs-200501-0002_definition-of-subgroups-for-fixed-regression-in-the-test-day-animal-model-for-milk-production-ofholsteincattle.php |
| _version_ | 1797899330768601088 |
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| author | L. Zavadilová E. Němcová J. Přibyl J. Wolf |
| author_facet | L. Zavadilová E. Němcová J. Přibyl J. Wolf |
| author_sort | L. Zavadilová |
| collection | DOAJ |
| description | The investigation was based on roughly 3.9, 2.7 and 1.7 million test-day records from first, second and third lactation, respectively, sampled from 596 200 Czech Holstein cows between the years 1991 and 2002. Breeding values were estimated from multi-lactation random-regression test-day models which contained the fixed effect of herd-test day, fixed regression on days in milk and random regressions on the animal level and the permanent environmental effect. Third degree Legendre polynomials (with four coefficients) were used for both the fixed and random regressions. The models differed in fixed regression. In Analysis I, 96 subclasses were defined according to age at calving, season and year of calving within lactation. In Analysis II, days open were additionally included as a grouping factor resulting in 480 subclasses. Rank correlations over 0.98 between both analyses were observed for breeding values for sires. Grouping according to Analysis I was recommended. |
| first_indexed | 2024-04-10T08:28:15Z |
| format | Article |
| id | doaj.art-4068fdc082d4484ab55670016c91bb72 |
| institution | Directory Open Access Journal |
| issn | 1212-1819 1805-9309 |
| language | English |
| last_indexed | 2024-04-10T08:28:15Z |
| publishDate | 2005-01-01 |
| publisher | Czech Academy of Agricultural Sciences |
| record_format | Article |
| series | Czech Journal of Animal Science |
| spelling | doaj.art-4068fdc082d4484ab55670016c91bb722023-02-23T03:32:17ZengCzech Academy of Agricultural SciencesCzech Journal of Animal Science1212-18191805-93092005-01-0150171310.17221/3976-CJAScjs-200501-0002Definition of subgroups for fixed regression in the test-day animal model for milk production ofHolsteincattle in theCzech RepublicL. Zavadilová0E. Němcová1J. Přibyl2J. Wolf3Research Institute of Animal Production in Prague, Czech RepublicResearch Institute of Animal Production in Prague, Czech RepublicResearch Institute of Animal Production in Prague, Czech RepublicResearch Institute of Animal Production in Prague, Czech RepublicThe investigation was based on roughly 3.9, 2.7 and 1.7 million test-day records from first, second and third lactation, respectively, sampled from 596 200 Czech Holstein cows between the years 1991 and 2002. Breeding values were estimated from multi-lactation random-regression test-day models which contained the fixed effect of herd-test day, fixed regression on days in milk and random regressions on the animal level and the permanent environmental effect. Third degree Legendre polynomials (with four coefficients) were used for both the fixed and random regressions. The models differed in fixed regression. In Analysis I, 96 subclasses were defined according to age at calving, season and year of calving within lactation. In Analysis II, days open were additionally included as a grouping factor resulting in 480 subclasses. Rank correlations over 0.98 between both analyses were observed for breeding values for sires. Grouping according to Analysis I was recommended.https://cjas.agriculturejournals.cz/artkey/cjs-200501-0002_definition-of-subgroups-for-fixed-regression-in-the-test-day-animal-model-for-milk-production-ofholsteincattle.phptest-day model with random regressionfixed regression subgroupslactation curvesmilk yielddairy cattle |
| spellingShingle | L. Zavadilová E. Němcová J. Přibyl J. Wolf Definition of subgroups for fixed regression in the test-day animal model for milk production ofHolsteincattle in theCzech Republic Czech Journal of Animal Science test-day model with random regression fixed regression subgroups lactation curves milk yield dairy cattle |
| title | Definition of subgroups for fixed regression in the test-day animal model for milk production ofHolsteincattle in theCzech Republic |
| title_full | Definition of subgroups for fixed regression in the test-day animal model for milk production ofHolsteincattle in theCzech Republic |
| title_fullStr | Definition of subgroups for fixed regression in the test-day animal model for milk production ofHolsteincattle in theCzech Republic |
| title_full_unstemmed | Definition of subgroups for fixed regression in the test-day animal model for milk production ofHolsteincattle in theCzech Republic |
| title_short | Definition of subgroups for fixed regression in the test-day animal model for milk production ofHolsteincattle in theCzech Republic |
| title_sort | definition of subgroups for fixed regression in the test day animal model for milk production ofholsteincattle in theczech republic |
| topic | test-day model with random regression fixed regression subgroups lactation curves milk yield dairy cattle |
| url | https://cjas.agriculturejournals.cz/artkey/cjs-200501-0002_definition-of-subgroups-for-fixed-regression-in-the-test-day-animal-model-for-milk-production-ofholsteincattle.php |
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