References of "Gengler, Nicolas"
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See detailGenetic relationships between body condition score and reproduction traits in Canadian Holstein and Ayrshire first-parity cows.
Bastin, Catherine ULiege; Loker, Sarah; Gengler, Nicolas ULiege et al

in Journal of Dairy Science (2010), 93(5), 2215-28

The objective of this study was to investigate the genetic relationship between body condition score (BCS) and reproduction traits for first-parity Canadian Ayrshire and Holstein cows. Body condition ... [more ▼]

The objective of this study was to investigate the genetic relationship between body condition score (BCS) and reproduction traits for first-parity Canadian Ayrshire and Holstein cows. Body condition scores were collected by field staff several times over the lactation in herds from Quebec, and reproduction records (including both fertility and calving traits) were extracted from the official database used for the Canadian genetic evaluation of those herds. For each breed, six 2-trait animal models were run; they included random regressions that allowed the estimation of genetic correlations between BCS over the lactation and reproduction traits that are measured as a single lactation record. Analyses were undertaken on data from 108 Ayrshire herds and 342 Holstein herds. Average daily heritabilities of BCS were close to 0.13 for both breeds; these relatively low estimates might be explained by the high variability among herds and BCS evaluators. Genetic correlations between BCS and interval fertility traits (days from calving to first service, days from first service to conception, and days open) were negative and ranged between -0.77 and -0.58 for Ayrshire and between -0.31 and -0.03 for Holstein. Genetic correlations between BCS and 56-d nonreturn rate at first insemination were positive and moderate. The trends of these genetic correlations over the lactation suggest that a genetically low BCS in early lactation would increase the number of days that the primiparous cow was not pregnant and would decrease the chances of the primiparous cow to conceive at first service. Genetic correlations between BCS and calving traits were generally the strongest at calving and decreased with increasing days in milk. The correlation between BCS at calving and maternal calving ease was 0.21 for Holstein and 0.31 for Ayrshire and emphasized the relationship between fat cows around calving and dystocia. Genetic correlations between calving traits and BCS during the subsequent lactation were moderate and favorable, indicating that primiparous cows with a genetically high BCS over the lactation would have a greater chance of producing a calf that survived (maternal calf survival) and would transmit the genes that allowed the calf to be born more easily (maternal calving ease) and to survive (direct calving ease). [less ▲]

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See detailShort communication: Genetic relationship between calving traits and body condition score before and after calving in Canadian Ayrshire second-parity cows.
Bastin, Catherine ULiege; Loker, Sarah; Gengler, Nicolas ULiege et al

in Journal of Dairy Science (2010), 93(9), 4398-403

The objective of this study was to investigate the genetic relationship between body condition score (BCS) and calving traits (including calving ease and calf survival) for Ayrshire second-parity cows in ... [more ▼]

The objective of this study was to investigate the genetic relationship between body condition score (BCS) and calving traits (including calving ease and calf survival) for Ayrshire second-parity cows in Canada. The use of random regression models allowed assessment of the change of genetic correlation from 100 d before calving to 335 d after calving. Therefore, the influence of BCS in the dry period on subsequent calving could be studied. Body condition scores were collected by field staff several times over the lactation in 101 herds from Quebec and calving records were extracted from the official database used for Canadian genetic evaluation of calving ease. Daily heritability of BCS increased from 0.07 on d 100 before calving to 0.25 at 335 d in milk. Genetic correlations between BCS at different stages ranged between 0.59 and 0.99 and indicated that genetic components for BCS did not change much over lactation. With the exception of the genetic correlation between BCS and direct calving ease, which was low and negative, genetic correlations between BCS and calving traits were positive and moderate to high. Correlations were the highest before calving and decreased toward the end of the ensuing lactation. The correlation between BCS 10 d before calving and maternal calving ease was 0.32 and emphasized the relationship between fat cows before calving with dystocia. Standards errors of the genetic correlations estimates were low. Genetic correlations between BCS and calf survival were moderate to high and favorable. This indicates that cows with a genetically high BCS across lactation would have a greater chance of producing a calf that survived (maternal calf survival) and that they would transmit genes that allow the calf to survive (direct calf survival). [less ▲]

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See detailGenetic variability of milk components based on mid-infrared spectral data.
Soyeurt, Hélène ULiege; Misztal, I.; Gengler, Nicolas ULiege

in Journal of Dairy Science (2010), 93(4), 1722-1728

The aim of this study was to estimate the genetic parameters of the mid-infrared (MIR) milk spectrum represented by 1,060 data points per sample. The dimensionality of traits was reduced by principal ... [more ▼]

The aim of this study was to estimate the genetic parameters of the mid-infrared (MIR) milk spectrum represented by 1,060 data points per sample. The dimensionality of traits was reduced by principal components analysis. Therefore, 46 principal components describing 99.03% of the phenotypic variability were used to create 46 new traits. Variance components were estimated using canonical transformation. Heritability ranged from 0 to 0.35. Twenty-five out of 46 studied traits showed a permanent environment variance greater than genetic variance. Eight traits showed heritability greater than 0.10. Variances of original spectral traits were obtained by back transformation. Heritabilities for each spectral data points ranged from 0.003 to 0.42. In particular, 3 MIR regions showing moderate to high heritability estimates were of potential genetic interest. Heritabilities for specific wave numbers, linked with common milk traits (e.g., lipids, lactose), were similar to those estimated for these traits. This research confirms the genetic variability of the MIR milk spectrum and, therefore, the genetic variation of milk components. The objective of this study was to better understand the genetics of milk composition and, maybe in the future, to select animals to improve milk quality. [less ▲]

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See detailImprovement and validation of milk fatty acid predictions using mid-infrared spectrometry
Soyeurt, Hélène ULiege; McParland, Sinead; Berry, Donagh et al

in Proceedings of the Bristish Society of Animal Science and the Agricultural Research Forum (2010)

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See detailUsing body condition score to select for better reproductive performance
Bastin, Catherine ULiege; Loker, Sarah; Gengler, Nicolas ULiege et al

Article for general public (2010)

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See detailDevelopment of a new crossbred based evaluation for carcass quality of Piétrain boars in the Walloon Region of Belgium
Dufrasne, Marie ULiege; Hammami, Hedi ULiege; Jaspart, Véronique et al

in Book of Abstract of the 61st Annual Meeting of the European Association for Animal Production (2010)

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See detailDevelopment of a new crossbred based evaluation for carcass quality of Piétrain boars in the Walloon Region of Belgium
Dufrasne, Marie ULiege; Hammami, Hedi ULiege; Jaspart, Véronique et al

Poster (2010)

The aim of this study was to develop a genetic evaluation model to estimate the genetic merit of Piétrain boars for some carcass quality traits. These boars are now evaluated on performances recorded on ... [more ▼]

The aim of this study was to develop a genetic evaluation model to estimate the genetic merit of Piétrain boars for some carcass quality traits. These boars are now evaluated on performances recorded on their crossbred progeny fattened in a central test station. Data provided by the on-farm performance recording system were utilized in this study. Traits analysed were backfat thickness (BF) and lean meat percentage (%meat). The data file contains 60 546 records measured on pigs between 150 and 300 days of age. Model developed was a multitrait animal model. Fixed effects were sex, contemporary groups and heterosis, modeled as regression on heterozygosity. Random effects were additive genetic and permanent environment, modeled by random regressions using linear splines, and residual. Variance components were estimated by restricted maximum likelihood (REML) method on random samples of the total dataset and then confirmed by a Gibbs sampling algorithm on the total dataset. Fit of the model was tested by computing residuals from a BLUP (Best Linear Unbiased Prediction) evaluation. BF and %meat have a high heritability that increase with age. These two traits are also highly genetically correlated. Mean residuals are not significantly different from zero for both traits. Given that BF and %meat had high heritability, genetic improvement of carcass quality is possible by selection on these two traits. Like residuals are close to zero for both traits, it seems that model developed explain a great proportion the variance in each traits. [less ▲]

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See detailDevelopment of a new genetic evaluation model for carcass quality based on crossbred performances of Piétrain boars in the Walloon Region of Belgium
Dufrasne, Marie ULiege; Hammami, Hedi ULiege; Jaspart, Véronique et al

Conference (2010)

In context of the development of the genetic evaluation system of Piétrain boars for crossbred performances, a genetic evaluation model was developed for the estimation of genetic merit of boars for ... [more ▼]

In context of the development of the genetic evaluation system of Piétrain boars for crossbred performances, a genetic evaluation model was developed for the estimation of genetic merit of boars for backfat thickness (BF) and meat percentage (%meat). The model developed was a random regression model using linear splines on age which knots at 175, 200 and 250 days. Variance components were estimated by restricted maximum likelihood and Gibbs sampling. Estimated heritability from 150 to 300 days increased from 0.56 to 0.75 for BF and from 0.55 to 0.69 for %meat. Genetic correlation between BF and %meat varied between -0.90 and -0.93 from 150 to 300 days. According to the study of residuals, the developed model was considered to fit well the data especially between 175 and 250 days of age. [less ▲]

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See detailDevelopment of a new genetic evaluation model for carcass quality based on crossbred performances of Piétrain boars in the Walloon Region of Belgium
Dufrasne, Marie ULiege; Hammami, Hedi ULiege; Jaspart, Véronique et al

in Proceedings of the 9th World Congress on Genetics Applied to Livestock Production (2010)

In context of the development of the genetic evaluation system of Piétrain boars for crossbred performances, a genetic evaluation model was developed for the estimation of genetic merit of boars for ... [more ▼]

In context of the development of the genetic evaluation system of Piétrain boars for crossbred performances, a genetic evaluation model was developed for the estimation of genetic merit of boars for backfat thickness (BF) and meat percentage (%meat). The model developed was a random regression model using linear splines on age which knots at 175, 200 and 250 days. Variance components were estimated by restricted maximum likelihood and Gibbs sampling. Estimated heritability from 150 to 300 days increased from 0.56 to 0.75 for BF and from 0.55 to 0.69 for %meat. Genetic correlation between BF and %meat varied between -0.90 and -0.93 from 150 to 300 days. According to the study of residuals, the developed model was considered to fit well the data especially between 175 and 250 days of age. [less ▲]

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See detailA robust method for simultaneous estimation of single gene and polygenic effects in dairy cows using externally estimated breeding values as prior information
Buske, Bernd ULiege; Szydlowski, Maciej; Gengler, Nicolas ULiege

in Journal of Animal Breeding & Genetics (2010), 127(4), 272-279

The aim of this study was to develop a robust method to estimate single gene and random polygenic animal effects simultaneously in a small field dataset with limited pedigree information. The new method ... [more ▼]

The aim of this study was to develop a robust method to estimate single gene and random polygenic animal effects simultaneously in a small field dataset with limited pedigree information. The new method was based on a Bayesian approach using additional prior information on the distribution of externally estimated breeding values. The field dataset consisted of 40 269 test-day records for milk performance traits for 1455 genotyped dairy cows for the 11 bp-deletion in the coding sequence of the myostatin gene. For all traits, estimated additive effects of the favoured wild-type allele (‘+’ allele) were smaller when applying the new method in comparison with the application of a conventional mixed inheritance test-day model. Dominance effects of the myostatin gene showed the same behaviour but were generally lower than additive effects. Robustness of methods was tested using a data-splitting technique, based on the correlation of estimated breeding values from two samples, with one-half of the data eliminated randomly from the first sample and the remaining data eliminated from the second sample. Results for 100 replicates showed that the correlation between split datasets when prior information included was higher than the conventional method. The new method led to more robust estimations for genetic effects and therefore has potential for use when only a small number of genotyped animals with field data and limited pedigree information are available. [less ▲]

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See detailFemale fertility expression in Walloon dairy cattle
Vanderick, Sylvie ULiege; Bastin, Catherine ULiege; Gengler, Nicolas ULiege

in Proceedings of the 9th World Congress on Genetics Applied to Livestock Production, Leipzig, Germany, 1-6 August, 2010 (2010)

A useful method to express female fertility of the Walloon dairy cattle using direct and indirect female fertility information was considered. Data were based on results of the genetic evaluation of ... [more ▼]

A useful method to express female fertility of the Walloon dairy cattle using direct and indirect female fertility information was considered. Data were based on results of the genetic evaluation of pregnancy rate for 606,328 Holstein cows and on INTERBULL proofs of female fertility for 88,496 bulls. A direct female fertility index (DFF), using INTERBULL proofs, was developed from results of a principal component analysis carried out on 6 published foreign female fertility indexes. An indirect female fertility index (IFF) was also developed from ten other traits evaluated in Walloon Region. Theory of selection index was used to combine DFF and IFF in a global index called combined female fertility index (CFF). This index allowed young bulls to have better reliabilities with an average increase of 12% leading to extra 4,019 of publishable bulls for female fertility. [less ▲]

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See detailEstimation des effets du gène culard sur les caractères de production laitière au sein du rameau Blanc Bleu Belge de type mixte
Colinet, Frédéric ULiege; Gengler, Nicolas ULiege

in 16ièmes Rencontres Recherches Ruminants, Paris, les 2 et 3 Décembre 2009 (2009, December)

Le rameau Blanc Bleu Belge de type mixte (BBm) est apprécié pour sa rusticité, sa longévité, une bonne santé ainsi que pour ses bonnes performances de reproduction. Une délétion de 11 paires de base ... [more ▼]

Le rameau Blanc Bleu Belge de type mixte (BBm) est apprécié pour sa rusticité, sa longévité, une bonne santé ainsi que pour ses bonnes performances de reproduction. Une délétion de 11 paires de base (allèle mh) au sein du gène de la myostatine engendre le syndrome d’hypertrophie musculaire (plus connu sous le nom de type culard ; d’ailleurs, cet allèle mh est souvent appelé le gène culard). Bien que cet allèle mh soit très présent au sein du rameau Blanc Bleu Belge de type viandeux, seulement 41 et 39 % des animaux BBm sont respectivement mh/mh et mh/+. <br />Etant donné l’importance des effets du gène culard sur la conformation viandeuse des animaux et de son rôle potentiel indirect en production laitière, il nous a semblé intéressant de tenir compte de sa présence lors de l’évaluation génétique des animaux BBm. Néanmoins, il n’est pas envisageable et concevable de génotyper tous les individus de la population BBm. Dès lors, il a fallu modifier légèrement le modèle mixte utilisé pour pouvoir y incorporer ce génotype connu pour certains animaux. La méthodologie ici présentée permet l’estimation simultanée des effets polygéniques (plus connus sous le terme « valeur d’élevage », VE) et de l’effet du gène culard. [less ▲]

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See detailSystème d'évaluation génétique des verrats Piétrain en Wallonie
Dufrasne, Marie ULiege; Gengler, Nicolas ULiege

Diverse speeche and writing (2009)

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See detailSustainable dairy farming - A case study of Holsteins in a developed and an emerging country
Hammami, Hedi ULiege; Rekik, Boulbaba; Bormann, Jeanne et al

Conference (2009, September 23)

Sustainability of breeding programs under the flow of exchange among various environments are conditioned by the ability of genotypes to adjust sufficiently their phenotypes in response to changes in ... [more ▼]

Sustainability of breeding programs under the flow of exchange among various environments are conditioned by the ability of genotypes to adjust sufficiently their phenotypes in response to changes in their new bio-physical conditions, and also by the capabilities of farmers to balance between environmental, ethical, social. and economic aspects. The objective of this paper was to quantify the effectiveness of genetic responses from indirect selection in high- and low- to medium- input systems using Luxembourg and Tunisian Hoisteins. The magnitude of genotype-by-environment interaction (GxE) for production traits was firstly investigated based on the country border delimitation as environmental character state. Secondly, three herd management levels reflecting feeding and management intensity were identified in each country and GxE was investigated within and across country environments. Significant GxE was detected for milk yield and persistency with large differences in genetic and permanent environmental variances between the 2 countries. Genetic correlations for 305-d milk yield and persistency between Luxembourg and Tunisia were 0.60 and 0.36. Low rank correlations obtained between estimated breeding values of common sires translated a significant re-ranking between the 2 countries. Within-country environments analysis show that the magnitude of GxE varied from only scaling effects resulting from heterogeneous variances in high-input systems to considerable re-ranking of common sires under limited feeding resources, low management care, and stressful conditions in low-input systems. Overall, this study shows that substantial differences exist between Hoisteins in terms of their sensitivity to production environ ment suspecting the sustainability of the dairying system. In high-input systems, GxE effects are expected to be easily managed but harmful effects of intensive dairy systems should be considered. Selection of breeds under less intensive production systems respecting the ruminant's specificities should be encouraged. In law-input systems, selection for adaptive traits under their specifie conditions and improvement of management conditions and husbandry practices are needed. [less ▲]

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See detailSteps to implement animal breeding for improved nutritional quality of bovine milk
Gengler, Nicolas ULiege; Soyeurt, Hélène ULiege

Conference (2009, September 23)

Animal improvement is always directed towards a given selection objective. These objectives in dairy cattle have been changing in the last forty years passing from simple yield only potentially associated ... [more ▼]

Animal improvement is always directed towards a given selection objective. These objectives in dairy cattle have been changing in the last forty years passing from simple yield only potentially associated with type, towards more complex ones including also functional traits as fertility and longevity. Milk composition has been selected too in most countries, however focussing only on major components, fat and protein. During the last years interest in milk quality traits, especially nutritionally quality has been increasing. Implementing breeding for additional traits first requires that animals can be evaluated for them because data is available and they are heritable enough. The objective of our research was to develop the needed steps to implement animal breeding for improved nutritional quality. Until recently data for fatty acid (FA) composition could not be obtained easily. However calibration equations for mid-infrared (MIR) spectrometry data generated in routine milk analysis done during milk recording were developed. They are used in routine in Belgium (Walloon Region) and Luxembourg and generate MIR data used to predict FA for up to 100.000 cows for every test date, therefore up to a maximum of 1 million test-day records. Multivariate test-day models were developed that allow estimating genetic parameters and ultimately breeding values as soon as enough data is available. Daily heritabilities estimated ranged between 0.1 and 0.4 showing that sufficient genetic differences exist. Because of the lack of historical data correlated traits as milk yield, fat and protein content will be analyse together with FA. For the future research on correlations between FA and other economically important traits will be done. Results are needed to integrate FA in the selection objectives. Because of the relative lack of historical data there is a high interest to research using genomic information to provide combined breeding values. [less ▲]

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See detailEnvironmental and genetic sources of variability of stearoyl Coenzyme-A desaturase 9 activity during and across lactations
Arnould, Valérie ULiege; Gengler, Nicolas ULiege; Soyeurt, Hélène ULiege

Conference (2009, September 23)

Milk fatty acid (FA) profile is far from the optimal fat composition in regards to human health. Different natural sources of variation such as feeding or genetics could be used to modify the contents of ... [more ▼]

Milk fatty acid (FA) profile is far from the optimal fat composition in regards to human health. Different natural sources of variation such as feeding or genetics could be used to modify the contents of unsaturated fatty acids. The impact of feeding is well described; however, genetics effects on the milk FA composition are not well studied. Increasing the unsaturated fatty acids contents of bovine milk could have the potential to raise the nutritive and therapeutic values of dairy products. The stearoyl Coenzyme-A desaturase 9 (delta-9) gene was identified as a potential functional candidate gene affecting milk fat composition in dairy cattle. The objective of this research was to study the genetic variability on this enzyme activity across lactations. A total of 199,977 test-day records were obtained from 29,603 Holstein cows in first lactation, 154,267 records from 23,453 Holstein cows in second lactation, and 173,244 records from 75,887 Holstein cows in third and later lactations. The used model was a multiple-trait random regressions test-day model. Fixed effects were: herd x date of test, and class of age. Random effects were: herd x year of calving, permanent environmental, additive genetic, and residual effects. The studied traits were milk yield, protein content, percentage of fat, monounsaturated fatty acids estimated by mid-infrared spectrometry, and the ratios reflecting the delta-9 activity. Obtained heritability estimates of delta-9 as well as the genetic and phenotypic correlations varied across lactations. These results suggest potential improvements of milk fat composition based on delta-9 activity using animal selection and appropriate management practices. [less ▲]

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