Reference : Short communication: Genetic variation of saturated fatty acids in Holsteins in the W...
Scientific journals : Article
Life sciences : Animal production & animal husbandry
Life sciences : Genetics & genetic processes
http://hdl.handle.net/2268/69958
Short communication: Genetic variation of saturated fatty acids in Holsteins in the Walloon region of Belgium
English
Arnould, Valérie mailto [Université de Liège - ULg > Sciences agronomiques > Zootechnie >]
Hammami, Hedi mailto [Université de Liège - ULg > Sciences agronomiques > Zootechnie >]
Soyeurt, Hélène mailto [Université de Liège - ULg > Sciences agronomiques > Zootechnie >]
Gengler, Nicolas mailto [Université de Liège - ULg > Sciences agronomiques > Zootechnie >]
18-Aug-2010
Journal of Dairy Science
American Dairy Science Association
93
4391-4397
Yes (verified by ORBi)
International
0022-0302
1525-3198
Champaign
IL
[en] spline ; legendre polynomials ; random regression test-day model
[en] Random regression test-day models using Legendre polynomials are commonly used for the estimation of genetic parameters and genetic evaluation for test-day milk production traits. However, some researchers have reported that these models present some undesirable properties such as the overestimation of variances at the edges of lactation. Describing genetic variation of saturated fatty acids expressed in milk fat might require the testing of different models. Therefore, 3 different functions were used and compared to take into account the lactation curve: (1) Legendre polynomials with the same order as currently applied for genetic model for production traits; 2) linear splines with 10 knots; and 3) linear splines with the same 10 knots reduced to 3 parameters. The criteria used were Akaike’s information and Bayesian information criteria, percentage square biases, and log-likelihood function. These criteria indentified Legendre polynomials and linear splines with 10 knots reduced to 3 parameters models as the most useful. Reducing more complex models using eigenvalues seemed appealing because the resulting models are less time demanding and can reduce convergence difficulties, because convergence properties also seemed to be improved. Finally, the results showed that the reduced spline model was very similar to the Legendre polynomials model.
Researchers
http://hdl.handle.net/2268/69958
http://www.journalofdairyscience.org/
http://www.journalofdairyscience.org/article/S0022-0302%2810%2900464-9/fulltext
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