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See detailEstimation of genetic parameters for birth weight, pre-weaning mortality and hot carcass weight in a crossbred population of pigs
Dufrasne, Marie ULg; Misztal, Ignacy; Tsuruta, Shogo et al

in Journal of Animal Science (2012), 90(E-Suppl.3), 721

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See detailEstimation of genetic parameters for birth weight, pre-weaning mortality and hot carcass weight in a crossbred population of pigs
Dufrasne, Marie ULg; Misztal, Ignacy; Tsuruta, Shogo et al

Conference (2012, July 18)

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See detailEstimation of genetic parameters for birth weight, preweaning mortality, and hot carcass weight of crossbred pigs
Dufrasne, Marie ULg; Misztal, Ignacy; Tsuruta, Shogo et al

in Journal of Animal Science (2013), 91

Genetic parameters for birth weight (BWT), preweaning mortality (PWM), and hot carcass weight (HCW) were estimated for a crossbred pig population to determine if BWT could be used as an early predictor ... [more ▼]

Genetic parameters for birth weight (BWT), preweaning mortality (PWM), and hot carcass weight (HCW) were estimated for a crossbred pig population to determine if BWT could be used as an early predictor for later performances. Sire genetic effects for those traits were estimated to determine if early selection of purebred sires used in crossbreeding could be improved. Data were recorded from one commercial farm between 2008 and 2010. Data were from 24,376 crossbred pigs from Duroc sires and crossbred Large White × Landrace dams and included 24,376 BWT and PWM records, and 13,029 HCW records. For the analysis, PWM was considered as a binary trait (0 for live or 1 for dead piglet at weaning). A multi-trait threshold-linear animal model was used, with animal effect divided into sire genetic and dam effects; the dam effects included both genetic and environmental variation due to the absence of pedigree information for crossbred dams. Fixed effects were sex and parity for all traits, contemporary groups for BWT and HCW, and age at slaughter as a linear covariable for HCW. Random effects were sire additive genetic, dam, litter, and residual effects for all traits, and contemporary group for PWM. Heritability estimates were 0.04 for BWT, 0.02 for PWM, and 0.12 for HCW. Ratio between sire genetic and total estimated variances was 0.01 for BWT and PWM, and 0.03 for HCW. Dam and litter variances explained respectively 14% and 15% of total variance for BWT, 2% and 10% for PWM, and 3% and 8% for HCW. Genetic correlations were −0.52 between BWT and PWM, 0.55 between BWT and HCW, and -0.13 between PWM and HCW. Selection of purebred sires for higher BWT of crossbreds may slightly improve survival until weaning and final market weight at the commercial level. [less ▲]

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See detailEstimation of genetic parameters for longitudinal measurements of feed intake in Piétrain sire lines
Dufrasne, Marie ULg; Jaspart, Véronique; Wavreille, José et al

in Book of Abstracts of the 63rd Annual Meeting of the European Association of Animal Science (2012)

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See detailEstimation of genetic parameters for longitudinal measurements of feed intake in Piétrain sire lines
Dufrasne, Marie ULg; Jaspart, Véronique; Wavreille, José et al

Conference (2012, August 30)

The aim of this study was to estimate the genetic parameters for longitudinal measurements of feed intake (FI) in a crossbred population of pigs to develop a genetic evaluation model for the estimation of ... [more ▼]

The aim of this study was to estimate the genetic parameters for longitudinal measurements of feed intake (FI) in a crossbred population of pigs to develop a genetic evaluation model for the estimation of breeding values for FI of Piétrain boars. Data were collected on crossbred pigs in test station in the context of the genetic evaluation system of Piétrain boars in the Walloon Region of Belgium. Trait analyzed was daily FI (DFI). Because there were no facilities to record individual DFI in the Walloon test station, individual DFI were assumed to be the total pen FI divided by the number of pigs per pen. The edited dataset consisted of 3,902 measurements of DFI recorded on 1,975 crossbred pigs from 75 purebred Piétrain sires and 150 Landrace dams from the hyperprolific Landrace K+ line. A random regression animal model with fixed effects of sex and pen, and random effects of additive genetic, permanent environment and residual was developed in this study. Random additive genetic and permanent environment effects were modeled with linear splines with knots located at 75, 100, 175 and 210 d. The mean DFI was 1.979 kg/d with a SD of 0.479 kg/d. Estimated heritability for DFI increased with age from 0.02 at 75 d to 0.30 at 210 d. Estimated genetic correlation between age decreased when age interval increased. These preliminary results are consistent with literature. However, additional research are ongoing to test alternative random regression models that should be better than using splines for longitudinal performance of DFI. Furthermore, genetic relationship between DFI and other production traits, like growth and carcass traits, must be analyzed. [less ▲]

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See detailEstimation of genetic parameters for methane indicator traits based on milk fatty acids in dual purpose Belgian blue cattle
Kandel, Purna Bhadra ULg; Soyeurt, Hélène ULg; Gengler, Nicolas ULg

in Communications in Agricultural and Applied Biological Sciences (2012, February 10), 77(1), 21-25

The genetic parameters of CH4 indicators were estimated by single trait test-day models from 16,825 records collected on Walloon Dual Purpose Belgium Blue cows in their first 3 lactations. Fatty acid ... [more ▼]

The genetic parameters of CH4 indicators were estimated by single trait test-day models from 16,825 records collected on Walloon Dual Purpose Belgium Blue cows in their first 3 lactations. Fatty acid based CH4 indicators published in the literature were predicted from milk mid-infrared spectra using 597 calibration samples. For the indicator showing the highest link (R2 =0.88) with SF6 CH4 data, the average daily heritability was 0.21, 0.20 and 0.10 for each lactation, respectively. The sire genetic variability was on average 2.82 kg2 of CH4 per lactation. The genetic difference between the sires having cows eructing higher and lower CH4 was 10 kg of CH4 averaged per lactation. In conclusion, CH4 indicators can be predicted by MIR and the genetic variability of these traits seems to exist. [less ▲]

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See detailEstimation of genetic parameters for quantitative trait loci for dairy traits in the French Holstein population.
Druet, Tom ULg; Fritz, S.; Boichard, D. et al

in Journal of Dairy Science (2006), 89(10), 4070-6

A marker-assisted selection program (MAS) has been implemented in dairy cattle in France. The efficiency of such a selection program depends on the use of correct genetic parameters for the marked ... [more ▼]

A marker-assisted selection program (MAS) has been implemented in dairy cattle in France. The efficiency of such a selection program depends on the use of correct genetic parameters for the marked quantitative trait loci (QTL). Therefore, the objective of this study was to estimate the proportion of genetic variance explained by 4 QTL described in previous studies (these QTL are segregating on chromosomes 6, 14, 20, and 26). Genotypes for 11 markers were available for 3,974 bulls grouped within 54 sire families of the French Holstein population undergoing MAS. The parameters were estimated for 4 QTL and 5 dairy traits: milk, fat and protein yields, and fat and protein percentages. The proportion of genetic variance explained by the QTL ranged from as low as 0.03 to 0.36%. Both lack of marker informativity and poor monitoring of QTL transmission might limit the accuracy of estimation. The QTL explained a larger proportion of genetic variance for milk composition traits. The QTL on chromosome 14 and chromosomes 6 and 20 have their largest influence on fat and protein percentages, respectively. The overall proportions of genetic variance explained by the QTL were 27.0, 30.7, 24.1, 48.2, and 33.6% for milk, fat and protein yields, and fat and protein percentages, respectively. These results clearly indicated that a large part of the genetic variance is explained by a small number of QTL and that their use in MAS might be beneficial for dairy cattle breeding programs. [less ▲]

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See detailEstimation of Genetic Parameters for Test Day Milk Yields of Moroccan Holstein Cows Using Random Regression Test Day Model
Tijani, Aziz; Rgayai, Brahim; Hammami, Hedi ULg et al

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

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See detailEstimation of Genetic Parameters for Test Day Milk Yields of Moroccan Holstein Cows Using Random Regression Test Day Model
Tijani, Aziz; Rgayai, Brahim; Hammami, Hedi ULg et al

Poster (2010, August 02)

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See detailEstimation of genetic parameters for test day records of dairy traits in the first three lactations.
Druet, Tom ULg; Jaffrezic, Florence; Ducrocq, Vincent

in Genetics, Selection, Evolution (2005), 37(3), 257-71

Application of test-day models for the genetic evaluation of dairy populations requires the solution of large mixed model equations. The size of the (co)variance matrices required with such models can be ... [more ▼]

Application of test-day models for the genetic evaluation of dairy populations requires the solution of large mixed model equations. The size of the (co)variance matrices required with such models can be reduced through the use of its first eigenvectors. Here, the first two eigenvectors of (co)variance matrices estimated for dairy traits in first lactation were used as covariables to jointly estimate genetic parameters of the first three lactations. These eigenvectors appear to be similar across traits and have a biological interpretation, one being related to the level of production and the other to persistency. Furthermore, they explain more than 95% of the total genetic variation. Variances and heritabilities obtained with this model were consistent with previous studies. High correlations were found among production levels in different lactations. Persistency measures were less correlated. Genetic correlations between second and third lactations were close to one, indicating that these can be considered as the same trait. Genetic correlations within lactation were high except between extreme parts of the lactation. This study shows that the use of eigenvectors can reduce the rank of (co)variance matrices for the test-day model and can provide consistent genetic parameters. [less ▲]

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See detailEstimation of genetic parameters for test-day records of French Holstein cows with an AI-REML algorithm
Druet, Tom ULg; Jaffrézic, F.; Ducrocq, V.

in Abstracts from the 2003 ADSA/ASAS joint annual meeting (2003)

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See detailEstimation of genetic parameters of racing traits of Arabian horses in Algeria
Tennah, Safia ULg; Kafidi, Nacereddine; Antoine-Moussiaux, Nicolas ULg et al

Poster (2013, August)

The results of the flat races organized in Algeria from 1995 to 2007 by the Algerian Horse Racing Society, were used to estimate genetic parameters of racing performances of Arabian horses. The data ... [more ▼]

The results of the flat races organized in Algeria from 1995 to 2007 by the Algerian Horse Racing Society, were used to estimate genetic parameters of racing performances of Arabian horses. The data consist of 36 492 race records, obtained from 913 horses. The pedigree file of the horses includes 1812 animals from 166 stallions and 392 mares. The analysis was performed on two traits: the logarithm of average annual virtual earnings per start (LAEV/S) and a normalized ranking (PERF). To identify the fixed effects to be included in the genetic model, a preliminary analysis was conducted using the General Linear Models (GLM) procedure from SAS software. The effects of age (3 to 8 years and older), sex (male or female), year (1995 to 2007) and the interaction between year of the race and age and between sex and age were included in the model for both traits. In addition, two random effects, a direct genetic effect of the animal and a permanent environmental effect were included in the mixed model. The variance components and genetic parameters were estimated by the restricted maximum likelihood (REML), procedure using the MTDFREML program. The analysis, using a repeatable animal model, led to the following estimation of genetic parameters: for LAEV/S, heritability was 0.23 (±0.04), while estimate of repeatability was 0.34 (±0.04). The heritability for the normalized ranking was higher, 0.37 (±0.05), indicating that this trait might be more appropriate for breeding programs of Arabian horses in Algeria. The repeatability estimate for the normalized ranking was 0.59 (±0.04) and the genetic correlation between this trait and LAEV/S was 0.79. [less ▲]

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See detailEstimation of genetic parameters of test-day records for milk yield for the first three lactations of French Holstein cows
Druet, Tom ULg; Jaffrézic, F.; Ducrocq, V.

in Book of Abstracts of the 54th Annual Meeting of the European Association for Animal Production (2003)

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See detailEstimation of genetic-parameters for growth, feed consumption, and conformation traits for double-muscled Belgian Blue bulls performance-tested in Belgium
Gengler, Nicolas ULg; Seutin, C.; Boonen, F. et al

in Journal of Animal Science (1995), 73(11), 3269-3273

For 1,442 Belgian Blue bulls performance-tested at the Centre de Selection de la Race Blanc-Bleue Belge, nine traits were observed: height at withers at 7 mo, height at withers at 13 mo, weight at 7 mo ... [more ▼]

For 1,442 Belgian Blue bulls performance-tested at the Centre de Selection de la Race Blanc-Bleue Belge, nine traits were observed: height at withers at 7 mo, height at withers at 13 mo, weight at 7 mo, weight at 13 mo, average feed consumption of concentrates, average daily gain, average feed consumption of concentrates per average daily gain, average feed consumption of concentrates per mean metabolic weight, and price per kilogram of live weight. This price is based on muscle conformation and is therefore used as muscle conformation score. Restricted maximum Likelihood with a derivative-free algorithm was used to estimate (co)variance components because there were different models and missing values per trait. Estimates of heritabilities were above .50 except for average feed consumption per average daily gain (.16) and average feed consumption per mean metabolic weight (.33). Estimates of genetic and phenotypic correlations between height at withers and weight traits were positive and moderate to high. Average daily gain showed a negative genetic correlation with weight at 7 mo (- .68) but had positive correlations with height at withers at 13 mo and weight at 13 mo (.22 and .43). Muscle conformation expressed as price per kilogram of live weight was related to low average feed consumption per average daily gain. Average feed consumption showed high correlations with weight at 7 mo and weight at 13 mo. Average feed consumption per average daily gain had a high negative genetic correlation with average daily gain (- .89). [less ▲]

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See detailEstimation of GFR by different creatinine- and cystatin-C-based equations in anorexia nervosa.
Delanaye, Pierre ULg; Cavalier, Etienne ULg; Radermecker, Régis ULg et al

in Clinical Nephrology (2009), 71(5), 482-91

Background: Patients with anorexia nervosa (AN) are at high risk of renal failure. Glomerular filtration rate (GFR) is overestimated when estimated by the creatinine-based equations. We have studied the ... [more ▼]

Background: Patients with anorexia nervosa (AN) are at high risk of renal failure. Glomerular filtration rate (GFR) is overestimated when estimated by the creatinine-based equations. We have studied the accuracy and precision of cystatin C-based equations. Method: 27 AN patients were included. GFR was measured with the chromium-51-ethylenediaminetetraacetate (51Cr-EDTA) method. We have compared the accuracy and precision of creatinine-based equations (MDRD and Cockcroft) with those of different new cystatin C-based equations. Results: The creatinine-based equations overestimate measured GFR, especially the MDRD study equation. All the cystatin C-based equations also overestimate measured GFR. The Cockcroft and Gault formula and the cystatin C-based equation published by Rule have the best accuracy and precision, but these last performances remain unsatisfactory. Conclusion: Both creatinine and cystatin C-based equations strongly overestimate measured in patients with AN. [less ▲]

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See detailEstimation of habitat quality based on plant community, and effects of isolation in a network of butterfly habitat patches
Sawchik, J.; Dufrêne, Marc ULg; Lebrun, Philippe

in Acta Oecologica (2003), 24(1), 25-33

Minimum viable site networks are crucial for many threatened species but their design is always a difficult procedure. The present study investigated methods to estimate habitat quality of patches, in an ... [more ▼]

Minimum viable site networks are crucial for many threatened species but their design is always a difficult procedure. The present study investigated methods to estimate habitat quality of patches, in an ecological network for five butterfly species (Brenthis ino, Clossiana selene, Lycaena helle, Lycaena hippothoe, Proclossiana eunomia) inhabiting wet meadows. Abundance predictions were performed on the basis of botanical relevés with a multiple-species approach combining canonical correspondence analysis and multiple regression. Models are defined on a reference site set and are evaluated on a test site set. All the fitted models predicted the abundance of the butterfly species considerably well (from 61 to 86% of the variation). We evaluated the potential consequences of isolation on local populations, by comparing predicted and observed abundance. It was expected that greater differences would be observed when sites were more isolated. On the test set, differences between predicted and observed abundance were largely correlated to site isolation for L. helle and P. eunomia. The most isolated sites had greater chances to be empty, even if they had high-quality habitat. Reciprocally, when the sites were less isolated, the abundance observed was always greater than predicted, seeming to confirm the role of rescue effects. © 2003 Éditions scientifiques et médicales Elsevier SAS. All rights reserved. [less ▲]

Detailed reference viewed: 13 (1 ULg)