References of "Journal of Animal Breeding & Genetics"
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See detailGenetic parameters for direct and maternal calving ease in Walloon dairy cattle based on linear and threshold models
Vanderick, Sylvie ULg; Troch, Thibault ULg; Gillon, Alain et al

in Journal of Animal Breeding & Genetics (2014), in press

Calving ease scores from Holstein dairy cattle in the Walloon Region of Belgium were analysed using univariate linear and threshold animal models. Variance components and derived genetic parameters were ... [more ▼]

Calving ease scores from Holstein dairy cattle in the Walloon Region of Belgium were analysed using univariate linear and threshold animal models. Variance components and derived genetic parameters were estimated from a dataset including 33,155 calving records. Included in the models were season, herd and sex of calf age of dam classes group of calvings interaction as fixed effects, herd year of calving, maternal permanent environment and animal direct and maternal additive genetic as random effects. Models were fitted with the genetic correlation between direct and maternal additive genetic effects either estimated or constrained to zero. Direct heritability for calving ease was about 8% with linear models and about 12% with threshold models. Maternal heritabilities were about 2% and 4%, respectively. Genetic correlation between direct and maternal additive effects was found to be not significantly different from zero. Models were compared in terms of goodness of fit and predictive ability. Criteria of comparison such as mean squared error, correlation between observed and predicted calving ease scores as well as between estimated breeding values were estimated from 85,118 calving records. The results provided few differences between linear and threshold models even though correlations between estimated breeding values from subsets of data for sires with progeny from linear model were 17% and 23 % greater for direct and maternal genetic effects, respectively, than from threshold model. For the purpose of genetic evaluation for calving ease in Walloon Holstein dairy cattle, the linear animal model without covariance between direct and maternal additive effects was found to be the best choice. [less ▲]

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See detailAn integration of external information for foreign stallions into the Belgian genetic evaluation for jumping horses
Vandenplas, Jérémie ULg; Janssens, Steven; Buys, Nadine et al

in Journal of Animal Breeding & Genetics (2013), 130(3), 209-217

The aim of this study was to test the integration of external information, i.e. foreign estimated breeding values (EBV) and the associated reliabilities (REL), for stallions into the Belgian genetic ... [more ▼]

The aim of this study was to test the integration of external information, i.e. foreign estimated breeding values (EBV) and the associated reliabilities (REL), for stallions into the Belgian genetic evaluation for jumping horses. The Belgian model is a bivariate repeatability Best Linear Unbiased Prediction animal model only based on Belgian performances while Belgian breeders import horses from neighbouring countries. Thereby, use of external information is needed as prior to achieve more accurate EBV. Pedigree and performance data contained 101,382 horses and 712,212 performances, respectively. After conversion to the Belgian trait, external information of 98 French and 67 Dutch stallions were integrated into the Belgian evaluation. Resulting Belgian rankings of the foreign stallions were more similar to foreign rankings according to the increase of the rank correlations of at least 12%. REL of their EBV were improved of at least 2% on average. External information was partially to totally equivalent to 4 years of contemporary horses’ performances or to all the stallions’ own performances. All these results showed the interest to integrate external information into the Belgian evaluation. [less ▲]

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See detailGenetic parameters of milk production traits and fatty acid contents in milk for Holstein cows in parity 1 – 3
Bastin, Catherine ULg; Soyeurt, Hélène ULg; Gengler, Nicolas ULg

in Journal of Animal Breeding & Genetics (2013), 130(2),

The objective of this study was to estimate genetic parameters of milk, fat, and protein yields, fat and protein contents, somatic cell count, and 17 groups and individual milk fatty acid (FA) contents ... [more ▼]

The objective of this study was to estimate genetic parameters of milk, fat, and protein yields, fat and protein contents, somatic cell count, and 17 groups and individual milk fatty acid (FA) contents predicted by mid-infrared spectrometry for first-, second- and third-parity Holstein cows. Edited data included records collected in the Walloon region of Belgium from 37 768 cows in parity 1, 22 566 cows in parity 2 and 8221 in parity 3. A total of 69 (23 traits for three parities) single-trait random regression animal test-day models were run. Approximate genetic correlations among traits were inferred from pairwise regressions among estimated breeding values of cow having observations. Heritability and genetic correlation estimates from this study reflected the origins of FA: de novo synthetized or originating from the diet and the body fat mobilization. Averaged daily heritabilities of FA contents in milk ranged between 0.18 and 0.47. Average daily genetic correlations (averaged across days in milk and parities) among groups and individual FA contents in milk ranged between 0.31 and 0.99. The genetic variability of FAs in combination with the moderate to high heritabilities indicated that FA contents in milk could be changed by genetic selection; however, desirable direction of change in these traits remains unclear and should be defined with respect to all issues of importance related to milk FA. [less ▲]

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See detailLDSO: A program to simulate pedigrees and molecular information under various evolutionary forces
Ytournel, F.; Teyssèdre, S.; Roldan, D. et al

in Journal of Animal Breeding & Genetics (2012), 129(5), 417-421

Simulations are a major tool to evaluate new statistical methods and optimize experimental designs in the genomic era. However, this can only be achieved when the simulations are close enough to reality ... [more ▼]

Simulations are a major tool to evaluate new statistical methods and optimize experimental designs in the genomic era. However, this can only be achieved when the simulations are close enough to reality, as well as diverse enough to be realistic. For mapping studies, it is thus critical to re-create as much as possible the forces generating linkage (mutation, random drift, changes in population sizes, selection and pedigree structure) and the mechanisms producing trait genetic architecture (additivity, dominance, epistasis). We present here a computer program (ldso) simulating these phenomena. Optional outputs provide statistics on the linkage disequilibrium (LD) structure and the identity by descent between chromosomal segments, facilitating further data analyses. Furthermore, ldso enables the simulation of genomic data in known pedigrees, which sticks as precisely as possible to recent population history and structures of the long-range LD, allowing optimization of fine-mapping strategies. © 2012 Blackwell Verlag GmbH. [less ▲]

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See detailFarmer's views and values to focus on cattle conservation policies: the case of eight European countries
Gandini, G; Martin-Collado, D; Colinet, Frédéric ULg et al

in Journal of Animal Breeding & Genetics (2012), 129

Our aim was to identify elements useful in designing policies and programmes for conservation of farm animal genetic resources, taking as case study a group of European local cattle breeds. We first ... [more ▼]

Our aim was to identify elements useful in designing policies and programmes for conservation of farm animal genetic resources, taking as case study a group of European local cattle breeds. We first investigated the implications of differences among countries in the policies and programmes to be developed. Secondly, we analysed key elements common to countries, which may affect local breed viability. We used the herd size trend expected by the farmer in the near future as an indicator of breed viability. Fifteen breeds, for a total of 355 farms, were surveyed. To take into account the multiple factors influencing breeds’ demographic trends, the questionnaire included economical, technical and social aspects. Among the major differences across countries was the perception of the farmer on the value attributed to the local breed by society. Concerning the elements common to countries and their association to breed viability, the greater the collaboration among farmers and the stakeholders’ appreciation as perceived by the farmer, the greater the viability of the farm. An opposite trend was observed for the age of the farmer. Older farmers generally planned to soon cease farming or decrease herd size, whereas young farmers planned to increase the size of their herds. Implications of including these elements in conservation polices are discussed. [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 ULg; Szydlowski, Maciej; Gengler, Nicolas ULg

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 detailAccessing genotype by environment interaction using within- and across-country test-day random regression sire models
Hammami, Hedi ULg; Rekik, Boulbaba; Soyeurt, Hélène ULg et al

in Journal of Animal Breeding & Genetics (2009), 126(5), 366-377

First-lactation test-day (TD) milk records of Luxembourg and Tunisian Holsteins were analysed for evidence of genotype by environment interaction (G · E). The joint data included 730 810 TD records of 87 ... [more ▼]

First-lactation test-day (TD) milk records of Luxembourg and Tunisian Holsteins were analysed for evidence of genotype by environment interaction (G · E). The joint data included 730 810 TD records of 87 734 cows and 231 common sires. Random regression TD sire models with fourth-order Legendre polynomials were used to estimate genetic parameters via within- and across-country analyses. Daily heritability estimates of milk yield from within-country analysis were between 0.11 and 0.32, and 0.03 and 0.13 in Luxembourg and Tunisia, respectively. Heritability estimates for 305-day milk yield and persistency (defined as the breeding value for milk yield on DIM 280 minus the breeding value on DIM 80) were lower for Tunisian Holsteins compared with the Luxembourg population. Specifically, heritability for 305-day milk yield was 0.16 for within- and 0.11 for across-country analyses for Tunisian Holsteins and 0.38 for within- and 0.40 for across-country analyses for Luxembourg Holsteins. Heritability for apparent persistency was 0.02 for both within and across-country analyses for Tunisian Holsteins and 0.08 for within and 0.09 for across-country analyses for Luxembourg Holsteins. Genetic correlations between the two countries were 0.50 for 305-day milk yield and 0.43 for apparent persistency. Moreover, rank correlations between the estimated breeding values of common sires for 305-day milk yield and persistency, estimated separately in each country, were low. Low genetic correlations are evidence for G · E for milk yield production while low rank correlations suggest different rankings of sires in both environments. Results from this study indicate that milk production of daughters of the same sires depends greatly on the production environment and that importing high merit semen for limited input systems might not be an effective strategy to improve milk production. [less ▲]

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See detailEstimation of genetic parameters and genome scan for 15 semen characteristics traits of Holstein bulls.
Druet, Tom ULg; Fritz, S.; Sellem, E. et al

in Journal of Animal Breeding & Genetics (2009), 126(4), 269-77

A QTL detection experiment was performed in French dairy cattle to search for QTL related to male fertility. Ten families, involving a total of 515 bulls, were phenotyped for ejaculated volume and sperm ... [more ▼]

A QTL detection experiment was performed in French dairy cattle to search for QTL related to male fertility. Ten families, involving a total of 515 bulls, were phenotyped for ejaculated volume and sperm concentration, number of spermatozoa, motility, velocity, percentage of motile spermatozoa after thawing and abnormal spermatozoa. A set of 148 microsatellite markers were used to realize a genome scan. First, genetic parameters were estimated for all traits. Semen production traits were found to have moderate heritabilities (from 0.15 to 0.30) while some of the semen quality traits such as motility had high heritabilities (close to 0.60). Genetic correlations among traits showed negative relationships between volume and concentration and between volume and most quality traits such as motility or abnormal sperm while correlations between concentration and these traits were rather favourable. Percentages of abnormal sperm were negatively related to quality traits, especially with motility and velocity of spermatozoa. Three QTL related to abnormal sperm frequencies were significant at p < 0.01. In total, 11 QTL (p < 0.05) were detected. However, the number of QTL detected was within the range of expected false positives. Because of the lack of power to find QTL in this design further analyses are required to confirm these QTL. [less ▲]

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See detailMulti-trait animal model estimation of genetic parameters for linear type and gait traits in the Belgian warmblood horse
Rustin, M.; Janssens, S.; Buys, N. et al

in Journal of Animal Breeding & Genetics (2009), 126(5), 378--386

Summary Genetic parameters for the height at withers, 27 linear type and six linear gait traits were estimated for the Belgian warmblood horse. Observations on 987 mares, mostly 3 years old, were analysed ... [more ▼]

Summary Genetic parameters for the height at withers, 27 linear type and six linear gait traits were estimated for the Belgian warmblood horse. Observations on 987 mares, mostly 3 years old, were analysed using a multi-trait animal model. The statistical model included appraiser, age and location (date × place of appraisal) as fixed effects. Genetic parameters were estimated using a canonical transformation and an expectation-maximization restricted maximum likelihood algorithm with an additional deceleration step. Estimates of heritability for the 33 linear traits were between 0.15 and 0.55. Heritability of the height at withers was 0.34 ± 0.06. Estimated genetic correlations ranged from −0.60 to 0.98 with an average SE of 0.10. The highest positive correlations were found among traits of walk and among traits of trot. Volume and the quality of legs were the most negatively correlated. Estimated genetic parameters indicated that the linear scoring system is a valuable tool to assess conformation. The full (co)variance matrix is now available for breeding value estimation to support selection for conformation and gaits. [less ▲]

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See detailDetection of quantitative trait loci affecting non-return rate in French dairy cattle.
Ben Jemaa, S.; Fritz, S.; Guillaum, F. et al

in Journal of Animal Breeding & Genetics (2008), 125(4), 280-8

The purpose of this study was to map quantitative trait loci (QTL) influencing female fertility estimated by non-return rate (NRR) in the French dairy cattle breeds Prim'Holstein, Normande and ... [more ▼]

The purpose of this study was to map quantitative trait loci (QTL) influencing female fertility estimated by non-return rate (NRR) in the French dairy cattle breeds Prim'Holstein, Normande and Montbeliarde. The first step was a QTL detection study on NRR at 281 days after artificial insemination on 78 half-sib families including 4993 progeny tested bulls. In Prim'Holstein, three QTL were identified on Bos taurus chromosomes BTA01, BTA02 and BTA03 (p < 0.01), whereas one QTL was identified in Normande on BTA01 (p < 0.05). The second step aimed at confirming these three QTL and refining their location by selecting and genotyping additional microsatellite markers on a sub-sample of 41 families from the three breeds using NRR within 56, 90 and 281 days after AI. Only the three QTL initially detected in Prim'Holstein were confirmed. Moreover, the analysis of NRR within 56, 90 and 281 days after AI allowed us to distinguish two FF QTL on BTA02 in Prim'Holstein, one for NRR56 and one for NRR90. Estimated QTL variance was 18%, 14%, 11.5% and 14% of the total genetic variance, respectively, for QTL mapping to BTA01, BTA02 (NRR90 and NRR56) and BTA03. [less ▲]

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

in Journal of Animal Breeding & Genetics (2008), 125(5), 330-338

Many genetic problems can be solved by Monte Carlo method. This often requires sampling genotype configurations over pedigree. Current available samplers are inefficient for large animal pedigrees. A new ... [more ▼]

Many genetic problems can be solved by Monte Carlo method. This often requires sampling genotype configurations over pedigree. Current available samplers are inefficient for large animal pedigrees. A new sampler suitable for large complex pedigrees has been developed and evaluated. The sampler uses simple and iterative peeling algorithms alternately. The sampler was compared to two other samplers on hypothetical pedigree of 79 individuals and recessive disease. The behaviour of the sampler was evaluated in four experimental designs on real bovine pedigree of 907 903 animals. The application of the sampler was also exemplified in identical by descent study. [less ▲]

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See detailEstimation of phenotypic and genetic parameters for weight gain and weight at fixed ages in the double-muscled Belgian Blue Beef breed using field records
Coopman, F.; Krafft, A.; Dewulf, J. et al

in Journal of Animal Breeding & Genetics (2007), 124(1), 20-25

In the double-muscled Belgian Blue beef (DM-BBB) breed, selection focuses on muscular conformation and not on weight gain and higher weight. There are very few studies on growth in the DM-BBB using field ... [more ▼]

In the double-muscled Belgian Blue beef (DM-BBB) breed, selection focuses on muscular conformation and not on weight gain and higher weight. There are very few studies on growth in the DM-BBB using field records. Therefore, farms have no available useful figures on weight at fixed ages and weight gain for the DM-BBB. This study describes and evaluates live weights of DM-BBB animals. All the data were gathered on farms in Belgium. It was found that a male DM-BBB weighs an average of 51 kg at birth, 98 kg at 3 months, 242 kg at 7 months, 430 kg at 13 months and 627 kg at 20 months. Between the age of 7 and 20 months, weight gain is more than 1200 g a day. Females weigh 47 kg at birth, 96 kg at 3 months, 189 kg at 7 months and 332 kg at 13 months. For males, estimates of heritability for weights at 7, 13 and 20 months were between 0.21 and 0.36. The heritability for weight gain between 13 and 20 months was 0.13. This demonstrates that it is possible to select for higher weights and for increased growth between 13 and 20 months. Animals having high weights at a young age (7 and 13 months) tend to have also high weight at slaughtering age (20 months; r(g) between 0.81 and 0.98), but no additional growth between 13 and 20 months (r(g) between -0.09 and 0.00). High weight at 20 months is partially due to growth between 13 and 20 months (r(g) = 0.49). [less ▲]

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See detailDetection of novel single-nucleotide polymorphisms (SNPs) in the CYP21 gene and association analysis of two SNPs for CYP21 and ESR2 with litter size in a commercial sow population
Buske, Bernd ULg; Sternstein, Ina; Reissmann, Monika et al

in Journal of Animal Breeding & Genetics (2006), 123(5), 343-348

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See detailAnalysis of properdin (BF) genotypes associated with litter size in a commercial pig cross population
Buske, Bernd ULg; Brunsch, Christa; Zeller, Karin et al

in Journal of Animal Breeding & Genetics (2005), 122(4), 259-263

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See detailComparison of external morphological traits of newborns to inner morphological traits of the dam in the double-muscled Belgian Blue Beef breed
Coopman, F.; Gengler, Nicolas ULg; Groen, A. F. et al

in Journal of Animal Breeding & Genetics (2004), 121(2), 128-134

In the double-muscled (DM) Belgian Blue Beef (BBB) breed, caesarean section (CS) is used as a routine management tool to prevent dystocia. This practice is criticized on animal welfare grounds. With ... [more ▼]

In the double-muscled (DM) Belgian Blue Beef (BBB) breed, caesarean section (CS) is used as a routine management tool to prevent dystocia. This practice is criticized on animal welfare grounds. With unassisted (natural) births, difficulties arise because of disproportion between the sizes of the newborn and inner pelvic sizes of the dam. In this study external morphological traits of newborns are compared with inner morphological traits of the dam. Results of this study indicate that in the DM-BBB, CS is the only means to successful calving. Therefore, no calving ease scores are available to select for less dystocia in this breed. Selection for fewer CS must be achieved by focusing on lower birth weight (BW) and decreased muscular conformation at birth, both having a sufficiently high heritability. Simultaneously, pelvic sizes of the dam should be increased. It is very likely that the look of the DM-BBB will change when selecting for less dystocia. [less ▲]

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