References of "Gengler, Nicolas"
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See detailGenotype x environment interaction for milk yield in Holsteins using Luxembourg and Tunisian populations.
Hammami, Hedi ULg; Rekik, Boulbaba; Soyeurt, Hélène ULg et al

in Journal of Dairy Science (2008), 91(9), 3661-71

Test-day (TD) milk yield records of first-lactation Holstein cows in Luxembourg and Tunisia were analyzed using within-and between-country random regression TD models. Edited data used for within-country ... [more ▼]

Test-day (TD) milk yield records of first-lactation Holstein cows in Luxembourg and Tunisia were analyzed using within-and between-country random regression TD models. Edited data used for within-country analysis included 661,453 and 281,913 TD records in Luxembourg and Tunisia, respectively. The joint data included 730,810 TD records of 87,734 cows and 231 common sires. Both data sets covered calving years 1995 to 2006. Fourth-order Legendre polynomials for random effects and a Gibbs sampling method were used to estimate variance components of lactation curve parameters in separate and joint analyses. Genetic variances of the first 3 coefficients from Luxembourg data were 46 to 69% larger than corresponding estimates from the Tunisian data. Inversely, the Tunisian permanent environment variances for the same coefficients were 52 to 65% larger than the Luxembourg ones. Posterior mean heritabilities of 305-d milk yield and persistency, defined as estimated breeding values (EBV) at 280 days in milk-EBV at 80 days in milk, from between-country analysis were 0.42 and 0.12 and 0.19 and 0.08 in Luxembourg and Tunisia, respectively. Heritability estimates for the same traits from within-country analyses, mainly from the Tunisian data, were lower than those from the joint analysis. Genetic correlations for 305-d milk yield and persistency between countries were 0.60 and 0.36. Product moment and rank correlations between EBV of common sires for 305-d milk yield and persistency from within-country analyses were 0.38 and 0.41 and 0.27 and 0.26, respectively. Differences between genetic variances found in both countries reflect different milk production levels. Moreover, low genetic and rank correlations suggest different ranking of sires in the 2 environments, which implies the existence of a genotype x environment interaction for milk yield in Holsteins. [less ▲]

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See detailPredicting bovine milk urea concentration for future test-day records in a management perspective
Bastin, Catherine ULg; Laloux, Laurent; Bertozzi, Carlo et al

in Proceedings of the British Society of Animal Science (2008)

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See detailOptiVal: Vers de nouveaux outils de gestion pour les éleveurs laitiers wallons, Prédire la réussite à l’insémination
Laloux, Laurent; Bastin, Catherine ULg; Glorieux, Géry et al

in 13ième Carrefour des Productions animales: L'Elevage des ruminants en question: vérités et contre-vérités: Gembloux, le 23 janvier 2008 (2008)

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See detailRelationship between lactoferrin, minerals, and somatic cells in bovine milk
Soyeurt, Hélène ULg; Arnould, Valérie ULg; Bruwier, Damien et al

in Journal of Dairy Science (2008), 91(E-Suppl. 1), 542

Selection for increased mastitis resistance is hampered by lack of available data. Currently, somatic cell count or score are proven indicators. However, it should be a priority to increase the number of ... [more ▼]

Selection for increased mastitis resistance is hampered by lack of available data. Currently, somatic cell count or score are proven indicators. However, it should be a priority to increase the number of available indicator traits for mastitis resistance. The aim of this research was to study the relationships among potential indicator traits as lactoferrin content, concentrations of major minerals in milk (calcium, Ca; sodium, Na; phosphore, P), and somatic cell count. First, 3 calibration equations Breeding and Genetics: Breeding for Milk Quality and Test-Day Model Applications J. Anim. Sci. Vol. 86, E-Suppl. 2/J. Dairy Sci. Vol. 91, E-Suppl. 1 543 were developed using partial least squares regressions to predict the contents of Ca, Na, and P in milk by mid-infrared spectrometry. A total of 1,609 milk samples were collected between March 2005 and May 2006 for 475 cows from 6 dairy breeds. Based on their spectral variability, 100 samples were selected using a principal components approach. The contents of these minerals were estimated by emission spectrometry (ICP-AES). The ratio of standard deviation to standard error of cross validation obtained for the equations predicted the contents of Ca, Na, and P were superior to 2 suggesting the use of these equations in this research. Second, the relationship between lactoferrin, minerals and somatic cells was studied using a random regressions multi-trait animal test-day model. A total of 57,973 milk samples were collected from 94 herds between April 2005 and January 2008 during milk recording in the Walloon part of Belgium. [less ▲]

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See detailApplication of forensic science technique to the management of an endangered horse population
Bömcke, Elisabeth ULg; Gengler, Nicolas ULg

in Journal of Animal Science (2008), 86(E-suppl.2), 433

Implementing conservation strategies needs the knowledge of relationships inside the concerned population. The aim of the study was to find tools to help breeders to manage their horse population. The ... [more ▼]

Implementing conservation strategies needs the knowledge of relationships inside the concerned population. The aim of the study was to find tools to help breeders to manage their horse population. The Skyros pony is an indigenous Greek breed. The breed risk status is defined as critical-maintained according to the criteria from the Food and Agriculture Organization. Partial pedigree information is available, but its quality is poor as the average number of generation-equivalents is under 0.8 for the first known generation and under 1.4 for the second to the fifth. Further, 99 living individuals were genotyped at 16 microsatellite loci in order to check the registered parentage. For ungenotyped animals, conditional expectation of gene contents was calculated given molecular and pedigree data. As said in other studies, the animal genetics literature often seems unaware of relevant developments in human genetics (and conversely). In this study, an approach called Familial Searching was tested. This is used in forensic science, in addition to matching DNA evidence directly to criminal profiles, to search for people (present in a database) who are related to an individual that left DNA evidence at a scene of crime. This method is based on the calculation of likelihood ratios (LR) between genotype of an individual and genotypes of each other individuals of the database. The pedigree was used as ‘local’ prior information, i.e. relating to specific pairs of individuals. General knowledge about the studied population (generation interval, sexual maturity, …) was considered as ‘global’ prior information. Including prior information reduced the number of comparisons from over 50%. First results showed that the parents were always classified into the 5 highest LR. These results simplified parentage verifications, it allowed the detection of 90% of false parentage (LR=0). New links were created in the pedigree through detection of unregistered parents, what involved a reduction of the percentage of animals with one or both unknown parents and consequently an increase of the number of generation-equivalents. The pedigree of the breed was thus improved. [less ▲]

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See detailAlternative modelling of body condition score from Walloon Holstein cows to develop management tools
Bastin, Catherine ULg; Laloux, Laurent; Gillon, Alain ULg et al

in Proceedings ICAR 36th Session (2008)

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See detailDetermination du profil en acides gras du lait par spectroscopie moyen infrarouge.
Dehareng, Frédéric; Soyeurt, Hélène ULg; Veselko, Didier et al

in 14 emes Recontres autour des recherches sur les ruminants, Paris, les 5et 6 Decembre 2007 (2007, December 01)

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See detailEtude comparative des performances de production laitiere de brebis de race Mouton Laitier Belge avec celles de brebis de race Lacaune.
Gillon, Alain ULg; Rondia, Pierre; Gengler, Nicolas ULg et al

in 14ièmes Recontres Recherches Ruminants, Paris, les 5 et 6 Décembre 2007 (2007, December)

La Wallonie compte une dizaine de producteurs de lait de brebis avec un cheptel variant de 30 à 250 individus par exploitation, pour la plupart de race « Mouton Laitier Belge » (MLB). Il s’agit d’un ... [more ▼]

La Wallonie compte une dizaine de producteurs de lait de brebis avec un cheptel variant de 30 à 250 individus par exploitation, pour la plupart de race « Mouton Laitier Belge » (MLB). Il s’agit d’un animal de type exclusivement laitier qui s’apparente fortement au mouton laitier frison dont l’effectif s’élève à un millier de têtes. La présence simultanée de brebis Lacaune (LAC) et de brebis MLB sur une même exploitation a permis la comparaison de leurs performances respectives grâce à une maîtrise du facteur « mode de conduite ». L’effectif restreint des populations étudiées constitue une limite à une extrapolation des résultats à l’ensemble des individus des races concernées mais donne néanmoins une certaine indication de leur potentiel de production respectif en région wallonne. [less ▲]

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See detailFirst results of body condition score modeling for Walloon Holstein cows
Bastin, Catherine ULg; Laloux, Laurent; Gillon, Alain ULg et al

Conference (2007, August 25)

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See detailFirst approaches for a combined use of microsatellites and pedigree data to estimate relationships.
Bömcke, Elisabeth ULg; Gengler, Nicolas ULg

in Book of Abstract of the 58th Annual Meeeting of the European Association for Animal Production (2007, August)

The main objective of conservation is the preservation of genetiv diversity. Among several tools recommended to measure genetic variability, relationships coefficients are often used. They can be ... [more ▼]

The main objective of conservation is the preservation of genetiv diversity. Among several tools recommended to measure genetic variability, relationships coefficients are often used. They can be estimated from pedigree but also from direct knowledge of hte genotype. The Skyros pony is an example of a small breed concerned by the management of genetic variability. However,the analysis of the pedigree showed its very poor quality. A part of the population was therefore genotyped for 16 microstellites and two estimators of relationships were tested: the Lynch & Ritland (L&R) (anly based on genotypes and described as having the best performances for all population comositionsof the mammal species) and a new estimator (developed for this study and combining pedigree and microsatellite information). In order to compare the results, a Principal Component Analysis (PCA) was performed. The new estimator explained a higher percentage of information within the 3 principal factors of the PCA (41.99%) than the L&R estimator (20.61%). The graphic PCA representation showed a better separation between the reference group and the rest of the populationin the case of the new estimator. The new estimator showed interesting preliminary results and results support interest in combining information in case of incomplete pedigrees and/or use of a limited number of markers. [less ▲]

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See detailFirst steps to model milk urea in a management perspective
Bastin, Catherine ULg; Gillon, Alain ULg; Laloux, Laurent et al

Conference (2007, July)

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See detailProduire de la viande et du lait avec la Blanc-Bleu Belge de type mixte
Bastin, Catherine ULg; Mayeres, Patrick; Bertozzi, Carlo et al

in 12ième Carrefour des Productions animales: Le marché de la viande bovine, enjeux et perspectives: Gembloux, le 24 janvier 2007 (2007, January 24)

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See detailProduire de la viande et du lait avec la Blanc-Bleu Belge de type mixte
Bastin, Catherine ULg; Mayeres, Patrick; Bertozzi, Carlo et al

Poster (2007, January 24)

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See detailA simple method to approximate gene content in large pedigree populations: application to the myostatin gene in dual-purpose Belgian Blue cattle
Gengler, Nicolas ULg; Mayeres, P.; Szydlowski, M.

in Animal (2007), 1(1), 21-28

Gene content is the number of copies of a particular allele in a genotype of an animal. Gene content can be used to study additive gene action of candidate gene. Usually genotype data are available only ... [more ▼]

Gene content is the number of copies of a particular allele in a genotype of an animal. Gene content can be used to study additive gene action of candidate gene. Usually genotype data are available only for a part of population and for the rest gene contents have to be calculated based on typed relatives. Methods to calculate expected gene content for animals on large complex pedigrees are relatively complex. in this paper we proposed a practical method to calculate gene content using a linear regression. The method does not estimate genotype probabilities but these can be approximated from gene content assuming Hardy-Weinberg proportions. The approach was compared with other methods on multiple simulated data sets for real bovine pedigrees of 1082 and 907 903 animals. Different allelic frequencies (0.4 and 0.2) and proportions of the missing genotypes (90, 70, and 50%) were considered in simulation. The simulation showed that the proposed method has similar capability to predict gene content as the iterative peeling method, however it requires less time and can be more practical for large pedigrees. The method was also applied to real data on the bovine myostatin locus on a large dual-purpose Belgian Blue pedigree of 235 133 animals. It was demonstrated that the proposed method can be easily adapted for particular pedigrees. [less ▲]

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See detailBayesian approach to integrate molecular data into genetic evaluations
Gengler, Nicolas ULg; Verkenne, Catherine

in Interbull Bulletin (2007), 37

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See detailGenetic Parameters of Butter Hardness Estimated by Test-Day Model
Soyeurt, Hélène ULg; Dehareng, Frédéric; Bertozzi, Carlo et al

in Interbull Bulletin (2007), 37

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See detailPrinicpal components approach for estimating heritability of mid-infrared (MIR) spectrum in bovine milk
Soyeurt, Hélène ULg; Tsuruta, Shogo; Misztal, Ignacy et al

in Book of Abstracts of the 58th Annual Meeting of the European Association for Animal Production (2007)

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