Reference : Environmental sensitivity for milk yield in Luxembourg and Tunisian Holsteins by herd ma...
Scientific journals : Article
Life sciences : Animal production & animal husbandry
Life sciences : Food science
Life sciences : Genetics & genetic processes
http://hdl.handle.net/2268/25295
Environmental sensitivity for milk yield in Luxembourg and Tunisian Holsteins by herd management level.
English
Hammami, Hedi mailto [Université de Liège - ULg > Gembloux Agro-Bio Tech > Gembloux Agro-Bio Tech > > >]
Rekik, Boulbaba mailto [>Ecole Supérieure d'Agriculture de Mateur (ESAM) > > >Productions animales > > > >]
Bastin, Catherine mailto [Université de Liège - ULg > Gembloux Agro-Bio Tech > Gembloux Agro-Bio Tech > > >]
Soyeurt, Hélène mailto [Université de Liège - ULg > Gembloux Agro-Bio Tech > Gembloux Agro-Bio Tech >]
Bormann, Jeanne mailto [Administration des Services Techniques de l'Agriculture, Luxembourg > > > >]
Stoll, Jean mailto [>Convis Herdbuch Service élevage et génétique > > >R&D > > >]
Gengler, Nicolas mailto [Université de Liège - ULg > Gembloux Agro-Bio Tech > Gembloux Agro-Bio Tech >]
2009
Journal of Dairy Science
American Dairy Science Association
92
9
4604-12
Yes (verified by ORBi)
International
0022-0302
1525-3198
Champaign
IL
[en] environmental sensitivity ; genotype by environment interaction ; genetic correlation ; herd management level
[en] Milk production data of Luxembourg and Tunisian Holstein cows were analyzed using herd management (HM) level. Herds in each country were clustered into high, medium, and low HM levels based on solutions of herd-test-date and herd-year of calving effects from national evaluations. Data from both populations included 730,810 test-day (TD) milk yield records from 87,734 first-lactation cows. A multi-trait, random regression TD model was used to estimate (co)variance components for milk yield within and across country HM levels. Additive genetic and permanent environmental variances of TD milk yields varied with management level in Tunisia and Luxembourg. Additive variances were smaller across HM levels in Tunisia than in Luxembourg, whereas permanent environmental variances were larger in Tunisian HM levels. Highest heritability estimates of 305-d milk yield (0.41 and 0.21) were found in high HM levels, whereas lowest estimates (0.31 and 0.12, respectively) were associated with low HM levels in both countries. Genetic correlations among Luxembourg HM levels were >0.96, whereas those among Tunisian HM levels were below 0.80. Respective rank orders of sires ranged from 0.73 to 0.83 across Luxembourg environments and from 0.33 to 0.42 across Tunisian HM levels indicating high re-ranking of sires in Tunisia and only a scaling effect in Luxembourg. Across-country environment analysis showed that estimates of genetic variance in the high, medium, and low classes of Tunisian environments were 45, 69, and 81% lower, respectively, than the estimate found in the high Luxembourg HM level. Genetic correlations among 305-d milk yields in Tunisian and Luxembourg HM environments ranged from 0.39 to 0.79. The largest estimated genetic correlation was found between the medium Luxembourg and high Tunisian HM levels. Rank correlations for common sires' estimated breeding values among HM environments were low and ranged from 0.19 to 0.39, implying the existence of genotype by environment interaction. These results indicate that daughters of superior sires in Luxembourg have their genetic expression for milk production limited under Tunisian environments. Milk production of cows in the medium and low Luxembourg environments were good predictors of that of their paternal half-sisters in the high Tunisian HM level. Breeding decisions in low-input Tunisian environment should utilize semen from sires with daughters in similar production environments rather than semen of bulls proven in higher management levels.
FNR Luxembourg
Researchers
http://hdl.handle.net/2268/25295
10.3168/jds.2008-1513
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