References of "Gengler, Nicolas"
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See detailDetection and use of single gene effects in large animal populations
Gengler, Nicolas ULg; Abras, S.; Szydlowski, M. et al

in Journal of Dairy Science (2007), 90(Suppl. 1), 376-376

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See detailGenetic variability of lactoferrin content estimated by mid-infrared spectrometry in bovine milk
Soyeurt, Hélène ULg; Colinet, Frédéric ULg; Arnould, Valérie ULg et al

in Journal of Dairy Science (2007), 90(9), 4443-4450

The effects of lactoferrin (LF) on the immune system have already been shown by many studies. Unfortunately, the current methods used to measure LF levels in milk do not permit the study of the genetic ... [more ▼]

The effects of lactoferrin (LF) on the immune system have already been shown by many studies. Unfortunately, the current methods used to measure LF levels in milk do not permit the study of the genetic variability of lactoferrin or the performance of routine genetic evaluations. The first aim of this research was to derive a calibration equation permitting the prediction of LF in milk by mid-infrared spectrometry (MIR). The calibration with partial least squares on 69 samples showed a ratio of standard error of cross-validation to standard deviation equal to 1.98. Based on this value, the calibration equation was used to establish an LF indicator trait (predicted LF; pLF) on a large number of milk samples (n = 7,690). A subsequent study of its variability was conducted, which confirmed that stage of lactation and lactation number influence the overall pLF level. Small differences in mean pLF among 7 dairy breeds were also observed. The pLF content of Jersey milk was significantly higher than that in Holstein milk. Therefore, the choice of breed could change the expected LF level. Heritability estimated for pLF was 19.7%. The genetic and phenotypic correlations between somatic cell score and pLF were 0.04 and 0.26, respectively. As somatic cell score increases in presence of mastitis, this observation seems to indicate that pLF, or a function of observed pLF, compared with expected LF might have potential as an indicator of mastitis. The negative genetic correlation (−0.36) between milk yield and pLF could indicate an undesirable effect of selection for high milk production on the overall LF level. [less ▲]

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See detailSampling genotype configurations in large complex pedigree
Szydlowski, M.; Gengler, Nicolas ULg

in Journal of Dairy Science (2007), 90(Suppl. 1), 668-668

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See detailValLait - Lactation Curves Modelling
Gillon, Alain ULg; Gengler, Nicolas ULg

Computer development (2007)

calculation of 305-d lactation yields for Walloon dairy cows

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See detailGenetic diversity and joint-pedigree analysis of two importing Holstein populations.
Hammami, Hedi ULg; Croquet, Coraline; Stoll, Jean et al

in Journal of Dairy Science (2007), 90(7), 3530-41

Genetic diversity and relatedness between 2 geographically distant Holstein populations (in Luxembourg and Tunisia) were studied by pedigree analysis. These 2 populations have similar sizes and structures ... [more ▼]

Genetic diversity and relatedness between 2 geographically distant Holstein populations (in Luxembourg and Tunisia) were studied by pedigree analysis. These 2 populations have similar sizes and structures and are essentially importing populations. Edited pedigrees included 140,392 and 151,381 animals for Tunisia and Luxembourg, respectively. To partially account for pedigree completeness levels, a modified algorithm was used to compute inbreeding. The effective numbers of ancestors were derived from probabilities of gene origin for the 2 populations of cows born between 1990 and 2000. The 10 ancestors with the highest contributions to genetic diversity in the cow populations accounted for more than 32% of the genes. Eight of these 10 ancestors were the same in both populations. The rates of inbreeding were different in the 2 populations but were generally comparable to those found in the literature for the Holstein breed. Average inbreeding coefficients per year, estimated from the data, ranged from 0.91 and 0.50 in 1990 to 3.10 and 2.12 in 2000 for the Tunisian and Luxembourg populations, respectively. Genetic links have also strengthened with time. Average additive relationships between the 2 populations were as high as 2.2% in 2000. Results suggest that it would be possible to investigate genotype by environment interactions for milk traits using the Tunisian and Luxembourg dairy populations. [less ▲]

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See detailEstimation of heritability and genetic correlations for the major fatty acids in bovine milk
Soyeurt, Hélène ULg; Gillon, Alain ULg; Vanderick, Sylvie ULg et al

in Journal of Dairy Science (2007), 90(9), 4435-4442

The current cattle selection program for dairy cattle in the Walloon region of Belgium does not consider the relative content of the different fatty acids (FA) in milk. However, interest by the local ... [more ▼]

The current cattle selection program for dairy cattle in the Walloon region of Belgium does not consider the relative content of the different fatty acids (FA) in milk. However, interest by the local dairy industry in differentiated milk products is increasing. Therefore, farmers may be interested in selecting their animals based on the fat composition. The aim of this study was to evaluate the feasibility of genetic selection to improve the nutritional quality of bovine milk fat. The heritabilities and correlations among milk yield, fat, protein, and major FA contents in milk were estimated. Heritabilities for FA in milk and fat ranged from 5 to 38%. The genetic correlations estimated among FA reflected the common origin of several groups of FA. Given these results, an index including FA contents with the similar metabolic process of production in the mammary gland could be used, for example, to increase the monounsaturated and conjugated fatty acids in milk. Moreover, the genetic correlations between the percentage of fat and the content of C14:0, C12:0, C16:0, and C18:0 in fat were −0.06, 0.55, 0.60, and 0.84, respectively. This result demonstrates that an increase in fat content is not directly correlated with undesirable changes in FA profile in milk for human health. Based on the obtained genetic parameters, a future selection program to improve the FA composition of milk fat could be initiated. [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

in Interbull Bulletin (2007), 37

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See detailFirst steps to model milk urea in a management perspective
Bastin, Catherine ULg; Gillon, Alain ULg; Gengler, Nicolas ULg

in Journal of Dairy Science (2007), 90 - Suppl 1

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See detailLinear and curvilinear effects of inbreeding on production traits for walloon Holstein cows
Croquet, Coraline; Mayeres, Patrick; Gillon, Alain ULg et al

in Journal of Dairy Science (2007), 90(1), 465-471

The nonlinear effects of inbreeding were studied by comparing linear and curvilinear regression models of phenotypic performances on inbreeding coefficients for production traits (milk, fat, and protein ... [more ▼]

The nonlinear effects of inbreeding were studied by comparing linear and curvilinear regression models of phenotypic performances on inbreeding coefficients for production traits (milk, fat, and protein yields) of Holstein cows in their first lactation. Three different regression models (linear, quadratic, and cubic) were introduced separately into a single-trait, single-lactation, random regression test-day model. The significance of the different regression coefficients was studied based on a t-test after estimation of error variances and covariances associated with the different regression coefficients. All of the tested regression coefficients were significantly different from 0. The traditional regression coefficients of milk, fat, and protein yields on inbreeding were, respectively, -22.10, -1.10, and -0.72 kg for Holstein cows in their first lactation. However, the estimates of 305-d production losses for various classes of animals based on inbreeding coefficients showed that the effect of inbreeding was not a linear function of the percentage of inbreeding. The 305-d milk yield loss profiles attributable to inbreeding, obtained by the various regression models, were different. However, for inbreeding coefficients between 0 and 10%, these differences were small. [less ▲]

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See detailVariation of lactoferrin content predicted by mid-infrared spectrometry (MIR)
Soyeurt, Hélène ULg; Colinet, Frédéric ULg; Arnould, Valérie ULg et al

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

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See detailGenetic parameters of the major fatty acid (FA) contents in cow milk
Soyeurt, Hélène ULg; Gillon, Alain ULg; Vanderick, Sylvie ULg et al

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

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

in Journal of Dairy Science (2007)

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See detailMapping of the bovine growth hormone secretagogue receptor (GHS-R) and polymorphism study in cattle
Colinet, Frédéric ULg; Eggen, André; Gengler, Nicolas ULg et al

Poster (2006, December)

A third control pathway of the Growth Hormone (GH) secretion has come into picture since the development of synthetic compounds known as Growth Hormone Secretagogues (GHSs). The GHS Receptor (GHS-R) and ... [more ▼]

A third control pathway of the Growth Hormone (GH) secretion has come into picture since the development of synthetic compounds known as Growth Hormone Secretagogues (GHSs). The GHS Receptor (GHS-R) and its subtype are abundantly located in the hypothalamus-pituitary unit, but are also distributed in other central areas and peripheral tissues. The GHS-R belongs to the G-protein coupled receptor family with seven transmembrane domain architecture. In order to determine the GHS-R gene sequence, total mRNA was extracted from abomasum and two types of GHS-R cDNA were identified. These two types are transcript variants (1a and 1b) of the same GHS-R gene. The gene encompasses two exons and a single intron. Using a 3000 Rad hybrid panel, the GHS-R gene was mapped to Bos taurus autosome 1 (BTA 1). This localization on BTA 1 agrees totally with comparative data between cattle and human since BTA 1 corresponds to part of human chromosome 3 where human GHSR is also mapped. By two-point analysis, most significantly linked marker are BL26 and BMS4031 (both LOD score : 5,66). Some studies detected different QTLs near these markers like for growth rate, carcass yield, milk portein and milk yield. In the cattle industry, it is of economical importance to increase plasma GH secretion because it is associated with faster growth, less fat stores and improved milk production. Being of economical importance and the detected QTLs near the GHS-R gene, it would be interesting to study the polymorphism on the bovine GHS-R gene. Screening for polymorphisms in the two exons on ten Belgian Blue bulls, ten Holsteins bulls and ten Limousin bulls revealed a total of four single nucleotide polymorphisms (SNPs): three SNPs are in the first exon and one SNP in the second exon. In order to evaluate if GHS-R could be involved in genetic variation for growth rate, carcass yield, milk portein and milk yield, an association study between SNPs on GHS-R gene and these traits could be performed in a major cattle population. [less ▲]

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See detailEstimating fatty acid content in cow milk using mid-infrared spectrometry
Soyeurt, Hélène ULg; Dardenne, Pierre; Dehareng, Frédéric et al

in Journal of Dairy Science (2006), 89(9), 3690-3695

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See detailIntégration de la longévité et redéfinition des objectifs de sélection
Félix, Alain; Vanderick, Sylvie ULg; Gengler, Nicolas ULg

Article for general public (2006)

La Wallonie participe aux évaluations pour la longévité d'INTERBULL depuis le mois de mars 2005. Cette période a permis de s'assurer de la validité et de la stabilité de nos méthodes d'évaluations mais ... [more ▼]

La Wallonie participe aux évaluations pour la longévité d'INTERBULL depuis le mois de mars 2005. Cette période a permis de s'assurer de la validité et de la stabilité de nos méthodes d'évaluations mais également d'étudier la prise en compte de ce nouveau paramètre dans l'objectif de sélection. [less ▲]

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See detailMapping and polymorphism of bovine ghreline gene
Colinet, Frédéric ULg; Eggen, André; Gengler, Nicolas ULg et al

in Proceedings of the 30th International Conference on Animal Genetics ISAG 2006 - Biodiversity, the future pass through preservation (2006, August)

Bovine ghrelin, a 27-amino-acid peptide has been identified in bovine oxyntic glands of the abomasum. It is an endogenous growth hormone secretagogue. Total mRNA was extracted from abomasum and complete ... [more ▼]

Bovine ghrelin, a 27-amino-acid peptide has been identified in bovine oxyntic glands of the abomasum. It is an endogenous growth hormone secretagogue. Total mRNA was extracted from abomasum and complete ghrelin mRNA was sequenced by rapid amplification of cDNA ends. The gene contains five exons and four introns with a short noncoding first exon of 17 bp similar to mouse and human ghrelin gene. Using a radiation hybrid panel, the gene was mapped to chromosome 22 near microsatellite markers UWCA49, BM4102, BMS1932, BM2613 and URB035 with good LOD Score. Some studies detected different QTLs near these markers like for milk fat percent, milk protein percent and somatic cell score. So, it would be interesting to study the polymorphism on the bovine ghrelin gene. Screening for polymorphisms in the five exons and the introns II and IV on ten Belgian Blue bulls, ten Holsteins bulls and ten Limousin bulls revealed a total of three single nucleotide polymorphisms. In order to evaluate if ghrelin could be involved in genetic variation for milk fat percent, milk protein percent and somatic cell score an association study between SNPs on ghrelin gene and these traits could be performed in a major cattle population. [less ▲]

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