References of "Hammami, Hedi"
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See detailLinking first lactation survival to milk yield and components and lactation persistency in Tunisian Holstein cows
Grayaa, Marwa ULiege; Vanderick, Sylvie ULiege; Rekik, Boulbaba et al

in Archiv für Tierzucht (2019), 65(1), 153160

Genetic parameters were estimated for first lactation survival defined as a binary trait (alive or dead to second calving) and the curve shape traits of milk yield, fat and protein percentages using ... [more ▼]

Genetic parameters were estimated for first lactation survival defined as a binary trait (alive or dead to second calving) and the curve shape traits of milk yield, fat and protein percentages using information from 25 981 primiparous Tunisian Holsteins. For each trait, shape curves (i.e. peak lactation, persistency), level of production adjusted to 305 days in milk (DIMs) for total milk yield (TMY), and average fat (TF %) and protein (TP %) percentages were defined. Variance components were estimated with a linear random regression model under three bivariate animal models. Production traits were modelled by fixed herd × test-day (TD) interaction effects, fixed classes of 25 DIMs × age of calving × season of calving interaction effects, fixed classes of pregnancy, random environment effects and random additive genetic effects. Survival was modelled by fixed herd × year of calving interaction effects and age of calving × season of calving interaction effects, random permanent environment effects, and random additive genetic effects. Heritability (h2) estimates were 0.03 (±0.01) for survival and 0.23 (±0.01), 0.31 (±0.01) and 0.31 (±0.01) for TMY, TF % and TP %, respectively. Genetic correlations between survival and TMY, TF % and TP % were 0.26 (±0.08), −0.24 (±0.06) and −0.13 (±0.06), respectively. Genetic correlations between survival and persistency for fat and protein percentages were −0.35 (±0.09) and −0.19 (±0.09), respectively. Cows that had higher persistencies for fat and protein percentages were more likely not to survive. [less ▲]

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See detailTemporal relationship between milk MIR predicted metabolic disorders and lameness events
Mineur, Axelle ULiege; Vanderick, Sylvie ULiege; Hammami, Hedi ULiege et al

in Book of Abstracts of the 68th Annual Meeting of the European Federation of Animal Science (2018, August 27)

Lameness is an often occurring consequence of various metabolic disorders, such as sub-acute ruminal acidosis (SARA) or ketosis. Recent research showed that these metabolic disorders can be predicted with ... [more ▼]

Lameness is an often occurring consequence of various metabolic disorders, such as sub-acute ruminal acidosis (SARA) or ketosis. Recent research showed that these metabolic disorders can be predicted with reasonable accuracy with mid-infrared (MIR) spectral data. In order to study the potentially complex temporal relationship between MIR predicted metabolic disorders and lameness events over the course of the lactation, data from 3895 cows on 122 farms, representing the Simmental, Brown-Swiss and Holstein breeds. A total of 38316 lameness and 11419 MIR records were collected over a period from July to December 2014 through the Efficient Cow Project. Lactations were subdivided into 30 days lactation stage classes. Milk MIR predicted metabolites such as ketone bodies, acetone, citrates and fatty acids (C18:1cis9), and lameness scores were averaged over animals and these classes. In order to assess the temporal link between occurrences of metabolic disorder and lameness events, correlations were computed between averaged metabolites and lameness scores across the lactation stage classes. Correlations tended to be higher when comparing predicted metabolites with lameness in the three following months, rather than the same one. Results showed differences between breeds, Simmentals showing lower correlations than Holsteins or Brown-Swiss. Especially very early values for milk MIR predicted metabolites (first month), and therefore suspected metabolic disorders, were correlated more strongly to later occurring lameness events in Brown Swiss. In Holsteins, higher correlation between metabolites and lameness were observed during later lactation. In general, given the use of classes, the correlations tended to be unstable. Alternative methods, such as covariance functions, might therefore be useful to get a clearer picture. However these first results seem to support the idea of temporal relationships between metabolic disorders and later lameness events during the lactation. [less ▲]

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See detailEarly-programming of dairy cattle, a potential explanation to the adaptation to climate change
Hammami, Hedi ULiege; Colinet, Frédéric ULiege; Bastin, Catherine et al

in Book of Abstracts of the 69th Annual Meeting of the European Federation of Animal Science (2018, August)

Breeding for robustness and considering genotype by environment interaction (G×E) is linked to adaptation. Recently, it has been established that gene expression can be affected by the environment during ... [more ▼]

Breeding for robustness and considering genotype by environment interaction (G×E) is linked to adaptation. Recently, it has been established that gene expression can be affected by the environment during the embryo development. The concept of early programming has been demonstrated in many settings. This study aimed to assess the impact of thermal stress when dairy cows been conceived on their lifetime performances. Studied traits were milk yield and some novel milk-based biomarkers, fertility (days open), health (somatic cell score and ketosis), and heat tolerance. Data used compromised 905,391 test day of 58,297 cows in parity 1 to 3 for production traits, health and ketosis status, 104,635 records of 48,125 cows for days open, and 399,449 test days recorded (linked with temperature humidity index values, THI) of 28,203 cows for heat tolerance trait. Date of conception was estimated using the next calving date of the cow and subtracting 280 d from the calving interval. Cows being conceived in summer (June- August) were considered as influenced by heat stress (environment 1) and those conceived in winter (December- February) as neutral-thermal conditions (environment 2). G×E was analysed by a multi-trait model for days open in which each of the 3 lactations measured in heat stress and thermo-neutral conditions were considered as separate traits. For the rest of the traits, it was analysed using reaction norm models, in which the trait is considered a function of an environmental descriptor (i.e. THI, days in milk) in the two discrete environments. First results showed that genetic correlations across both early-life defined environments and lactations were substantially lower than unity, implying that effects of genes for cows conceived under neutral-thermal conditions may be different of the effects for the same genes for cows conceived under heat stressed conditions. [less ▲]

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See detailTheoretical basis to extend single-step genomic prediction of dominance in a pig population
REIS MOTA, Rodrigo ULiege; Vanderick, Sylvie ULiege; Colinet, Frédéric ULiege et al

in Book of Abstracts of the 69th Annual Meeting of the European Federation of Animal Science (2018, August)

Single-step methods predict implicitly unknown gene content information of non-genotyped from known gene content for genotyped animals. This theory is well derived in an additive setting. There are ... [more ▼]

Single-step methods predict implicitly unknown gene content information of non-genotyped from known gene content for genotyped animals. This theory is well derived in an additive setting. There are reasons not to ignore the dominance context when working with partially genotyped populations. This study addressed several outstanding issues in this context. First, it presented the theoretical basis for dominance single-step genomic best linear unbiased prediction theory. A specific and important issue in all dominance setting is the handling of inbreeding. A total of five dominance single-step inverse matrices were tested and described as C1 to C5 by considering different parameterization (e.g. different ways to account for inbreeding) for pedigree-based and genomic relationships matrices. We simulated genotypes for real crossbred pig population (n=11,943 animals). The SNP effects were assumed to be equal to calculate true dominance values. We added random noise and used them as phenotypes. Accuracy was defined as correlation between true and predicted dominance breeding values. We applied five replicates and estimated accuracies between three situations: all (S1); non-genotyped (S2) and inbred non-genotyped animals (S3). Potential bias of predicted dominance values was assessed by regressing the true dominance values on predicted values. Accuracies of each tested matrix (C1 to C5) were 0.75, 0.33 and 0.35 in average, for S1, S2 and S3, respectively. The matrix C5 better performed and breeding values from C1 and C2 were more biased than those obtained by using C3, C4 and C5. We showed a useful approach to predict dominance gene contents for nongenotyped from genotyped animals. Better matrix compatibility can be obtained by re-scaling the pedigree-based and the genomic relationship matrices to obtain standardized diagonal elements equal to 1 minus the inbreeding coefficient, i.e. the C5 matrix. [less ▲]

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See detailMulti-omics data integration approach for resilience of dairy cattle to heat stress
Hammami, Hedi ULiege; Colinet, Frédéric ULiege; Bastin, Catherine et al

in Book of Abstracts of the 69th Annual Meeting of the European Federation of Animal Science (2018, August)

Breeding for resilience to heat stress (HS) is a topic where associating multiple omics data has the potential to get a better view of the issues and to allow significant advances to overcome undesirable ... [more ▼]

Breeding for resilience to heat stress (HS) is a topic where associating multiple omics data has the potential to get a better view of the issues and to allow significant advances to overcome undesirable consequences of future extreme weather scenarios. An example of omics is here epigenomics (e.g. early programming due to heat-stress) allowing new insights to explain biological mechanisms of resilience to HS and G×E interactions. Even if biological mechanisms are complex and still elusive, this study tried to use a holistic approach integrating milk-based biomarkers, climate conditions, and genomics. Data used included 65,907 third-lactation test-day records for production traits (milk, fat and protein yields), specific fatty acids (FA) and metabolites predicted from mid-infrared spectra (C4:0, C18:1cis9, long chain ‘LCFA’, mono- and unsaturated FA ‘MUFA and UFA’, acetone and BHB) of 9,327 Holstein cows. Phenotypes were merged with a temperature humidity index (THI) from public weather stations. For each trait, the response to THI was estimated via days in milk (DIM) × THI combination, and for each cow by using a random regression model with a common threshold of THI=62. The slope (heat tolerance)-to-intercept (general) genetic variance ratios increased as THI increased. They were higher during mid-lactation (140-245 DIM) for C18:1 cis9, acetone, BHB and for production traits, whereas higher in early lactation (≤125 DIM) for C4:0, LCFA, MUFA, and UFA. At extreme high THI scale, slope-to-intercept ratios for C18:1 cis9, MUFA, UFA, and LCFA were 3.8, 3.4, 3.1, 2.8 fold higher than milk yield. These findings indicate that tolerance to HS and traditional production trait responses to THI are marginally related, and changes in milk-based biomarkers under high THI better elucidate physiological and metabolic pathways in HS dairy cows. Ongoing genomic wide association studies will better explain genetic markers unravelling the biological background of resilience to HS. [less ▲]

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See detailEffect of milk yield and milk content curve shapes on first lactation survival in large herds
Grayaa, Marwa ULiege; Ben Gara, A.; Grayaa, S. et al

in Book of Abstracts of the 69th Annual Meeting of the European Federation of Animal Science (2018, August)

Genetic parameters of first lactation survival and curve shape traits of milk yield, fat and protein percentages were estimated using information of 25,981 primiparous Tunisian Holsteins belonging to ... [more ▼]

Genetic parameters of first lactation survival and curve shape traits of milk yield, fat and protein percentages were estimated using information of 25,981 primiparous Tunisian Holsteins belonging to large herds. For each trait lactation peak, apparent persistency, real persistency and level of production adjusted to 305 days in milk were defined. Variance components were estimated under three bivariate animal models with a linear random regression model. Milk yield as well as fat and protein percentages were modelled by fixed herd × test day interaction effects, fixed classes of 25 days in milk × age of calving × season of calving interaction effects, random environment effects, and random additive genetic effects. Survival was modelled by fixed herd × year of calving interaction effects, age of calving × season of calving interaction effects, random environment permanent effects, and random additive genetic effects. Heritability estimates were 0.03 for survival, 0.23, 0.29 and 0.30 for average milk yield, fat and protein percentages adjusted to 305 days in milk, respectively. Genetic correlations between survival and average milk yield, fat and protein percentages adjusted to 305 days in milk were 0.33, -0.33 and -0.14, respectively. Genetic correlations between survival and real persistency for fat and protein percentages were -0.24 and -0.15, respectively. Cows that had higher persistencies for fat and protein percentages, and therefore flatter fat and protein percentages curves, were more likely not to survive. This was due to higher fat percentages at the end of the lactation leading to the hypothesis that cows producing higher fat percentage dispose of less energy available for gestation and were therefore less likely to be or remain pregnant and, therefore, to survive. [less ▲]

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See detailGenetic parameters of novel mid-infrared predicted milk traits in three dual-purpose cattle breeds
Vanderick, Sylvie ULiege; Colinet, Frédéric ULiege; Mineur, Axelle ULiege et al

in Book of Abstracts of the 69th Annual Meeting of the European Federation of Animal Science (2018, August)

The objective of this study was to estimate genetic parameters of 39 novel mid-infrared predicted milk traits (e.g. nutritional quality, technological properties, metabolic status, environmental ... [more ▼]

The objective of this study was to estimate genetic parameters of 39 novel mid-infrared predicted milk traits (e.g. nutritional quality, technological properties, metabolic status, environmental fingerprint) for three dual purpose cattle breeds (i.e. Dual-Purpose Belgian Blue (dpBB), Montbéliarde (MON) and Normande (NOR)), which are also used in organic farming in the Walloon Region of Belgium, as part of the 2-Org-Cows project. Edited data included 21,287, 10,062 and 4,637 first-lactation test-day records collected in the Walloon region of Belgium from 2,988, 1,330 and 621 dpBB, MON and NOR cows, respectively. Genetic parameters were estimated using REML applied to single-trait random regression test-day models for six conventional traits (yields, contents and somatic cell score) and the 39 novel mid-infrared predicted milk traits. Results for conventional traits allowed comparison to literature showing values that were close to the expected ones. For novel traits, comparison with available literature values for Holstein breed showed generally similar estimated heritabilities. Reported average daily heritabilities estimated for the 39 novel traits tended to be higher for dpBB (0.13-0.64) than MON and NOR (0.03-0.60) breeds. Few novel traits showed large differences between breeds except between dpBB and NOR for milk composition traits. However, results for NOR breed have to be taken very carefully given the low number of animals. Even if the used methane prediction equation was not yet validated for these breeds, estimated average daily heritability was moderately high for dpBB (0.41) and MON (0.36) and moderate for NOR (0.23) indicating that this prediction might also be useful in these dual purpose breeds. [less ▲]

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See detailFirst study into the temporal relationship between metabolic disorders and lameness events over the course of a lactation
Mineur, Axelle ULiege; Egger-Danner, Christa; Sölkner, Johann et al

Conference (2018, June 25)

Lameness in dairy cows is an issue that can vary greatly in severity, and is of concern for both producers and consumers. Metabolic disorders are a major problem in themselves, and, next to this, can ... [more ▼]

Lameness in dairy cows is an issue that can vary greatly in severity, and is of concern for both producers and consumers. Metabolic disorders are a major problem in themselves, and, next to this, can cause lameness. Indeed, lameness is an often occurring consequence of various metabolic disorders, such as sub acute ruminal acidosis (SARA), ketosis or milk fever. The caused lameness event can occur weeks to months after the metabolic disorder making the detection of causality difficult. Moreover, detection of many metabolic disorders is very challenging and not straightforward. Mid-infrared (MIR) technology is already used for the prediction of major milk components, such as fat or protein, during routine milk recording and for milk payment. It was recently shown that this technology can also be used to predict novel components, linked to metabolic disorders of cows, such as ketone bodies, citrate and minerals. In the context of limiting the occurrence and severity of lameness, early prediction of lameness could help indicate the need to adapt the management and the environment of a cow at risk of lameness. Therefore, the aim of this study was to analyze the temporal link between metabolic disorders and lameness events, using locomotion scores of the cow and MIR based milk biomarkers for different metabolic disorders of her milk from previous test days. Data recorded between, July 2014 and December 2014, consisted of 9324 records, from 3895 cows and 122 farms. Correct definition of the response variable is an important aspect as extremes in lameness severity, expressed on lameness scales, were more easily predictable. First results were obtained using covariance functions on correlations computed between averaged metabolites and lameness scores, per animal, across the lactation stage classes. Correlations tended to be higher when comparing predicted metabolites with lameness in the three following months, rather than the same one, hinting at a temporal relationship. [less ▲]

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See detailSingle-step genomic analysis of dominance in a crossbred pig population
REIS MOTA, Rodrigo ULiege; Vanderick, Sylvie ULiege; Colinet, Frédéric ULiege et al

in Proceedings of the World Congress on Genetics Applied to Livestock Production (2018, February)

When all animals are genotyped, developments focused on dominance are well derived. However, this is rare in practice and adaptations are required. The dominant pedigree-based and genomic matrices should ... [more ▼]

When all animals are genotyped, developments focused on dominance are well derived. However, this is rare in practice and adaptations are required. The dominant pedigree-based and genomic matrices should be compatible in scale to be combined. We aimed to show how gene content flows from genotyped to non-genotyped animals. Scenarios where 0% (D), 20% (C20), 40% (C40) 60% (C60), 80% (C80), and 100% (G) of animals were genotyped were assumed in a crossbred pig population. Dominance variances were more sensitive by choosing G rather than D. D and C60 presented the highest dominance variances whereas G showed the lowest. The prediction accuracies increased as the number of genotyped animals increased. C40 provided less inflated dominance breeding values (1.01), and 55% of accuracy. Dominance relationships flew from genotyped to non-genotyped animals but single-step extension might worked because we used an approximation of D where inbreeding is ignored and due to simple family structure in our dataset. Thus, our approach might be useful but is not general as the original derivations of single-step. Genotyping strategies can be optimized based on the proportion of genotyped animals where 40% seemed to be optimal. [less ▲]

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See detailDefining and using novel milk composition based heat stress resilience traits in the context of genomic selection for more robust dairy cows in Wallonia
Mineur, Axelle ULiege; REIS MOTA, Rodrigo ULiege; Gengler, Nicolas ULiege et al

in Proceedings ICAR 2018 (2018)

Recent research showed the usefulness of using estimated breeding values (EBV) for mid-infrared (MIR) based biomarkers in genetic improvement. A novel class of biomarkers was defined based on modelling ... [more ▼]

Recent research showed the usefulness of using estimated breeding values (EBV) for mid-infrared (MIR) based biomarkers in genetic improvement. A novel class of biomarkers was defined based on modelling responses of milk composition (e.g., mid-infrared (MIR) based) to stress expressed on continuous scales using reaction norm models. Heat stress is an important aspect of dairy production even in temperate climates as shown in recent studies. Implementation of genomic selection for tolerance to heat stress is therefore not only an issue for Australian dairy cattle, a country that introduced recently such an evaluation. The question remains open if using milk composition based heat stress resilience genomically enhanced EBV (GEBV) is not a viable option. Genetic parameters were estimated for production and milk composition traits. Data included 155,977 test-day records for milk, fat, and protein yields, fat and protein percentages, 9 individual milk fatty acids (FA), 7 FA groups, 5 minerals, and 3 ketone bodies) predicted by mid-infrared spectrometry., and 7 FA groups. Data were from 21,375 first-lactation Holstein cows in 473 herds in the Walloon region of Belgium and were collected between 2008 and 2014. Test-day records were merged with daily temperature-humidity index (THI) values based on meteorological records from public weather stations. The maximum distance between each farm and its corresponding weather station was 13 km. Linear reaction norm models were used to estimate the intercept and slope responses of 23 traits to increasing THI values. Most yield and FA traits had phenotypic and genetic declines as THI increased, whereas C18:0, C18:1 cis-9, and 4 FA groups (unsaturated FA, monounsaturated FA, polyunsaturated FA, and long-chain FA) increased with THI. Moreover, the latter traits had the largest slope-to-intercept genetic variance ratios, which indicate that they are more affected by heat stress at high THI levels and therefore good candidate traits. Among all traits, C18:1 cis-9 was the most sensitive to heat stress. As this trait is known to reflect body reserve mobilization, using its response to THI could be a very affordable milk biomarker of heat stress for dairy cattle expressing the equilibrium between intake and mobilization, and therefore adaptation, under warm conditions. By including novel milk based composition traits to traditional production traits, correlations between EBVs and also GEBVs of those milk based traits and udder health, fertility and longevity increased considerably. This study demonstrated that milk composition resilience heat stress traits could be used as early indicators of robustness traits. Our results also suggest that marker information tend to lead to higher accuracies of prediction. Therefore, new options to improve robustness through genomic selection in Walloon Holsteins are now presented. [less ▲]

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See detailMilk mid-infrared spectra based biomarkers contributing to genetic improvement for udder health, fertility and longevity
Gengler, Nicolas ULiege; Mineur, Axelle ULiege; Vanderick, Sylvie ULiege et al

in Proceedings ICAR 2018 (2018)

Recent research showed the usefulness of using estimated breeding values (EBV) for midinfrared (MIR) based biomarkers in genetic improvement. Similarly, research has also shown that genetic variation is ... [more ▼]

Recent research showed the usefulness of using estimated breeding values (EBV) for midinfrared (MIR) based biomarkers in genetic improvement. Similarly, research has also shown that genetic variation is contained in the absorbance traits along the MIR band of wavelengths. Targeted extraction of the useful genetic variance can be achieved by the combination of EBV. Direct estimation of EBV for absorbance traits was demonstrated. Our first objective was to show that the reduction of the rank of the (co)variance structure among spectral traits is possible by imposing linear functions, even if these functions represent lower accuracy MIR biomarkers. MIR based biomarkers traits were derived from ongoing research in the FP7 GplusE project. In this study, the pathway from MIR spectra to the use in genetic improvement will be described. First, blood reference phenotypic data was collected on Holstein cows, at early lactation for IGF-1, glucose, urea, cholesterol, fructosamine, β- hydroxybutyric (BHB) acid and non-esterified fatty acids (NEFA). These traits were calibrated against corresponding MIR spectral data. Calibration 2 cv R ranged from 0.21 to 0.51, very low from a chemometrical point of view, but potentially sufficient to extract useful spectral variation. This was validated, using EBV that were based on these MIR predictions for 144,623 records (closest to days in milk 25), from 73,378 cows, in the Walloon region of Belgium. Single-trait, but multi-lactation (1, 2, 3+) models yielded h2 estimates ranging from 0.07 to 0.27. At least 20 daughters with novel traits and official EBV for udder health, fertility and longevity with minimum reliabilities of 70% were required; a total of 124 bulls met this criteria. Standard selection index theory would usually rely on prediction error variance minimisation and estimated population (co)variances. Alternatively in this study, Partial Least Squares were applied to EBV for the milk MIR based biomarkers to develop novel genetic predictors, for udder health, fertility and longevity, by extracting genetic variation along the wave band after rank reduction. Using all bulls, correlations between best predictors and EBV for udder health, fertility and longevity were at least 0.63, 0.67 and 0.62. Using selection index theory and based on significant increases of prediction abilities of longevity (0.76 compared to 0.68 from udder health or fertility alone) using also milk MIR based blood biomarkers, their potential contribution to genetic improvement of udder health, fertility and longevity will be demonstrated. [less ▲]

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See detailBayesian single-step genomic evaluations combining local and foreign information in Walloon Holsteins
Colinet, Frédéric ULiege; Vandenplas, J.; Vanderick, Sylvie ULiege et al

in Animal (2017)

Most dairy cattle populations found in different countries around the world are small to medium sized and use many artificial insemination bulls imported from different foreign countries. The Walloon ... [more ▼]

Most dairy cattle populations found in different countries around the world are small to medium sized and use many artificial insemination bulls imported from different foreign countries. The Walloon population in the southern part of Belgium is a good example for such a small-scale population. Wallonia has also a very active community of Holstein breeders requesting high level genetic evaluation services. Single-step Genomic BLUP (ssGBLUP) methods allow the simultaneous use of genomic, pedigree and phenotypic information and could reduce potential biases in the estimation of genomically enhanced breeding values (GEBV). Therefore, in the context of implementing a Walloon genomic evaluation system for Holsteins, it was considered as the best option. However, in contrast to multi-step genomic predictions, natively ssGBLUP will only use local phenotypic information and is unable to use directly important other sources of information coming from abroad, for example Multiple Across Country Evaluation (MACE) results as provided by the Interbull Center (Uppsala, Sweden). Therefore, we developed and implemented single-step Genomic Bayesian Prediction (ssGBayes), as an alternative method for the Walloon genomic evaluations. The ssGBayes method approximated the correct system of equations directly using estimated breeding values (EBV) and associated reliabilities (REL) without any explicit deregression step. In the Walloon genomic evaluation, local information refers to Walloon EBV and REL and foreign information refers to MACE EBV and associated REL. Combining simultaneously all available genotypes, pedigree, local and foreign information in an evaluation can be achieved but adding contributions to left-hand and right-hand sides subtracting double-counted contributions. Correct propagation of external information avoiding double counting of contributions due to relationships and due to records can be achieved. This ssGBayes method computed more accurate predictions for all types of animals. For example, for genotyped animals with low Walloon REL (<0.25) without MACE results but sired by genotyped bulls with MACE results, the average increase of REL for the studied traits was 0.38 points of which 0.08 points could be traced to the inclusion of MACE information. For other categories of genotyped animals, the contribution by MACE information was also high. The Walloon genomic evaluation system passed for the first time the Interbull GEBV tests for several traits in July 2013. Recent experiences reported here refer to its use in April 2016 for the routine genomic evaluations of milk production, udder health and type traits. Results showed that the proposed methodology should also be of interest for other, similar, populations. [less ▲]

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See detailGenetic evaluation for birth and conformation traits in dual-purpose Belgian Blue cattle using a mixed inheritance model
REIS MOTA, Rodrigo ULiege; Mayeres, P.; Bastin, Catherine et al

in Journal of Animal Science (2017)

The segregation of the causal mutation (mh) in the muscular hypertrophy gene in dual-purpose Belgian Blue (dpBB) cattle is considered to result in greater calving difficulty (dystocia). Establishing ... [more ▼]

The segregation of the causal mutation (mh) in the muscular hypertrophy gene in dual-purpose Belgian Blue (dpBB) cattle is considered to result in greater calving difficulty (dystocia). Establishing adapted genetic evaluations might overcome this situation through efficient selection. However, the heterogeneity of dpBB populations at the mh locus implies separating the major gene and other polygenic effects in complex modeling. The use of mixed inheritance models may be an interesting option because they simultaneously assume both influences. A genetic evaluation in dpBB based on a mixed inheritance model was developed for birth and conformation traits: gestation length (GL), calving difficulty (CD), birth weight (BiW), and body conformation score (BC). A total of 27,362 animals having records were used for analyses. The total number of animals in the pedigree used to build the numerator relationship matrix was 62,617. Genotypes at the mh locus were available for 2,671 animals. Missing records at this locus were replaced with genotype probabilities. A total of 13,221 (48.3%) were registered as dpBB, 1,287 (4.7%) as beef Belgian Blue, and 12,854 (47.0%) were unknown. From those 13,221dpBB animals, 650, 849, and 534 had double or single copies or no copy, respectively, of the causal mutation (mh) in the muscular hypertrophy gene, whereas 11,188 had missing genotypes. This heterogeneity at the mh locus may be the reason for high variability in the studied traits, that is, high heritability estimates of 0.33, 0.30, 0.38, and 0.43 for GL, CD, BiW, and BC, respectively. In general, additive (P < 0.05) and dominance (P < 0.001) allele substitution for calves and dams had significant impact for all traits. The moderate coefficient of genetic variation (27.80%) and high direct heritability (0.28) for CD suggested genetic variability in dpBB and possible genetic improvement through selection. This variability has allowed dpBB breeders to successfully apply mass selection in the past. Genetic trend means from 1988 to 2016 showed that sire selection for CD within genotype was progressively applied by breeders. The selection intensity was more important for CD in double-muscled lines than in segregated lines. Our study illustrated the possible confusion caused by the use of major genes in selection and the importance of fitting appropriate models such as mixed inheritance models that combine polygenic and gene content information. [less ▲]

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See detailUsing milk based biomarkers to monitor the physiological state of dairy cows in large populations
Hammami, Hedi ULiege; Colinet, Frédéric ULiege; Bastin, Catherine et al

in Book of Abstracts of the 68th Annual Meeting of the European Federation of Animal Science (2017, August 30)

Based on reference data from 6 GplusE project partner farms, several equations were developed to predict milk/ blood based biomarkers from milk mid-infrared spectra (MIR). Additional existing MIR ... [more ▼]

Based on reference data from 6 GplusE project partner farms, several equations were developed to predict milk/ blood based biomarkers from milk mid-infrared spectra (MIR). Additional existing MIR prediction equations of milk based biomarkers were included in this study. Data included predicted biomarkers for test-days between the 5th and the 49th DIM in the first 5 lactations of 57,240 Holstein cows. MIR spectra used to predict those biomarkers were collected since 2012 in 461 Belgian commercial farms enrolled in the official Walloon milk recording. Genetic parameters for each trait were estimated using single trait multi-lactation animal linear model. Additionnally bivariate models were used to investigate the genetic associations of MIR predicted milk and blood biomarkers. The lowest heritabilities estimates of 0.14, 0.15, and 0.17 were observed for milk urea, blood urea, and milk β-hydroxybutyrate (BHB) respectively. NEFA, BHB, and IGF-1 in blood have moderate heritability estimates (0.20-0.25). The highest heritabilties (0.31-0.35) concerned milk lactate dehydrogenase (LDH), milk glucose-6-phosphate, and blood glucose. Genetic correlations between lactations were relatively strong (≥0.74) for all indicators. Correlations between first- and later-lactations were the lowest (from 0.74 for blood NEFA to 0.90 for blood glucose). Highest correlations were observed between second- and later lactations (0.86 to 0.97 for milk BHB and milk LDH respectively). Urea and BHB in milk have strong genetic correlations with urea and BHB in blood (0.87 and 0.84 respectively). Additional validation of predictions equations in commercial farms and integration of reference data from other populations were needed, nevertheless first results showed value of these non-invasive biomarkers for routine monitoring and for breeding. [less ▲]

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See detailGenetic analysis of milk MIR predicted blood and milk biomarkers linked to the physiological status
Hammami, Hedi ULiege; Colinet, Frédéric ULiege; Bastin, Catherine et al

in Book of Abstracts of the 68th Annual Meeting of the European Federation of Animal Science (2017, August)

Based on reference data from 6 GplusE project partner farms, several equations were developed to predict milk/ blood based biomarkers from milk mid-infrared spectra (MIR). Additional existing MIR ... [more ▼]

Based on reference data from 6 GplusE project partner farms, several equations were developed to predict milk/ blood based biomarkers from milk mid-infrared spectra (MIR). Additional existing MIR prediction equations of milk based biomarkers were included in this study. Data included predicted biomarkers for test-days between the 5th and the 49th DIM in the first 5 lactations of 57,240 Holstein cows. MIR spectra used to predict those biomarkers were collected since 2012 in 461 Belgian commercial farms enrolled in the official Walloon milk recording. Genetic parameters for each trait were estimated using single trait multi-lactation animal linear model. Additionnally bivariate models were used to investigate the genetic associations of MIR predicted milk and blood biomarkers. The lowest heritabilities estimates of 0.14, 0.15, and 0.17 were observed for milk urea, blood urea, and milk β-hydroxybutyrate (BHB) respectively. NEFA, BHB, and IGF-1 in blood have moderate heritability estimates (0.20-0.25). The highest heritabilties (0.31-0.35) concerned milk lactate dehydrogenase (LDH), milk glucose-6-phosphate, and blood glucose. Genetic correlations between lactations were relatively strong (≥0.74) for all indicators. Correlations between firstand later-lactations were the lowest (from 0.74 for blood NEFA to 0.90 for blood glucose). Highest correlations were observed between second- and later lactations (0.86 to 0.97 for milk BHB and milk LDH respectively). Urea and BHB in milk have strong genetic correlations with urea and BHB in blood (0.87 and 0.84 respectively). Additional validation of predictions equations in commercial farms and integration of reference data from other populations were needed, nevertheless first results showed value of these non-invasive biomarkers for routine monitoring and for breeding. [less ▲]

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See detailAssessing the effect of pregnancy stage on milk composition of dairy cows using mid-infrared spectra
Laine, Aurélie ULiege; Bastin, Catherine; Grelet, Clément ULiege et al

in Journal of Dairy Science (2017), 100(4), 28632876

Changes in milk production traits (i.e., milk yield, fat, and protein contents) with the pregnancy stage are well documented. To our knowledge, the effect of pregnancy on the detailed milk composition has ... [more ▼]

Changes in milk production traits (i.e., milk yield, fat, and protein contents) with the pregnancy stage are well documented. To our knowledge, the effect of pregnancy on the detailed milk composition has not been studied so far. The mid-infrared (MIR) spectrum reflects the detailed composition of a milk sample and is obtained by a nonexhaustive and widely used method for milk analysis. Therefore, this study aimed to investigate the effect of pregnancy on milk MIR spectrum in addition to milk production traits (milk yield, fat, and protein contents). A model including regression on the number of days pregnant was applied on milk production traits (milk yield, fat, and protein contents) and on 212 spectral points from the MIR spectra of 9,757 primiparous Holstein cows from Walloon herds. Effects of pregnancy stage were expressed on a relative scale (effect divided by the squared root of the phenotypic variance); this allowed comparisons between effects on milk traits and on 212 spectral points. Effect of pregnancy stage on production traits were in line with previous studies indicating that the model accounted well for the pregnancy effect. Trends of the relative effect of the pregnancy stage on the 212 spectral points were consistent with known and observed effect on milk traits. The highest effect of the pregnancy was observed in the MIR spectral region from 968 to 1,577 cm−1. For some specific wavenumbers, the effect was higher than for fat and protein contents in the beginning of the pregnancy (from 30 to 90 or 120 d pregnant). In conclusion, the effect of early pregnancy can be observed in the detailed milk composition through the analysis of the MIR spectrum of bovine milk. Further analyses are warranted to explore deeply the use of MIR spectra of bovine milk for breeding and management of dairy cow pregnancy. [less ▲]

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See detailGrowth and carcass performances of guinea fowls reared under intensive system in Benin
Houndonougbo, Pascal ULiege; REIS MOTA, Rodrigo ULiege; Chrysostome, A.A.M. Christophe et al

in Livestock Research for Rural Development (2017), 29(10),

Several local guinea fowl varieties continued to be reared in extensive systems in Benin, even though productivity remains low. Improving rearing conditions through feeding and housing may enhance local ... [more ▼]

Several local guinea fowl varieties continued to be reared in extensive systems in Benin, even though productivity remains low. Improving rearing conditions through feeding and housing may enhance local guinea fowls productivity in Benin. Therefore, the objective of this study was to verify growth and carcass performances of five (Common, Bonaparte, Grey, White and Black) local guinea fowl varieties under intensive management conditions. At birth, 36 keets (young guinea fowls) of each identified variety were randomly divided into six batches and reared up to 16 weeks old under the same feeding and housing conditions. Body weights were recorded up to week 15. At week 16, carcass measurements were also taken. Growth performances and carcass measurements (morphological and visceral) differed among guinea fowl varieties. The heaviest body weight was observed in Common (832±24g) and the lowest in Black variety (698±39g). Highest carcass yield was observed in Grey variety. Liver weight, intestine length and caecum length were highest in Bonaparte variety. Gizzard weight and thigh proportion were highest in Common variety. Breast weight and breast proportion were highest in Grey guinea fowls. Body weight was moderately correlated with drumstick length, body length, wing size, tarsus diameter, thigh length and thorax circumference (range r = 0.34-0.60). The phenotypic variability and its impact on the characterization of these varieties implies that they are genetically different strains, supporting the hypothesis that the guinea fowl population in Benin presents opportunities for genetic improvement. [less ▲]

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See detailCharacteristic of Guinea Fowl breeding in West Africa: Review
Houndonougbo, Pascal ULiege; Bindelle, Jérôme ULiege; Chrysostome, A.A.M. Christophe et al

in Tropicultura (2017), 35(3), 222-230

Guinea fowl production in sub-Saharan Africa (SSA) is generally practiced under family and traditional rearing systems mainly for consumption and income generation, but this species plays also a major ... [more ▼]

Guinea fowl production in sub-Saharan Africa (SSA) is generally practiced under family and traditional rearing systems mainly for consumption and income generation, but this species plays also a major socio-cultural role in specific ceremonies. Birds are kept in free range or in confinement with outdoor access and fed on grain cereals, vegetables, edible termites and kitchen residues found in nature or occasionally supplied by the farmers. Several Guinea fowl varieties are observed and all are characterized by slow growth, high mortality of young and a relatively wild instinct. Although this avian species is less sensitive to some poultry diseases (Newcastle disease, Marek disease, Gumboro disease, etc), local guinea fowl are very sensitive to other poorly controlled diseases that require further study. These varieties differ greatly by their feather color, their morphological characteristics and growth performance, but further thorough and sustained research is needed to quantify these differences. Several researches established the nutritional requirements of local Guinea fowl but in terms of breeding, little works were done compared to chicken. Some recessive and dominant genes as well as genotypic differences were highlighted between varieties. [less ▲]

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See detailChallenges and priorities for modelling livestock health and pathogens in the context of climate change
Özkan, Şeyda; Vitali, Andrea; Lacetera, Nicola et al

in Environmental Research (2016), 151(Supplement C), 130-144

Climate change has the potential to impair livestock health, with consequences for animal welfare, productivity, greenhouse gas emissions, and human livelihoods and health. Modelling has an important role ... [more ▼]

Climate change has the potential to impair livestock health, with consequences for animal welfare, productivity, greenhouse gas emissions, and human livelihoods and health. Modelling has an important role in assessing the impacts of climate change on livestock systems and the efficacy of potential adaptation strategies, to support decision making for more efficient, resilient and sustainable production. However, a coherent set of challenges and research priorities for modelling livestock health and pathogens under climate change has not previously been available. To identify such challenges and priorities, researchers from across Europe were engaged in a horizon-scanning study, involving workshop and questionnaire based exercises and focussed literature reviews. Eighteen key challenges were identified and grouped into six categories based on subject-specific and capacity building requirements. Across a number of challenges, the need for inventories relating model types to different applications (e.g. the pathogen species, region, scale of focus and purpose to which they can be applied) was identified, in order to identify gaps in capability in relation to the impacts of climate change on animal health. The need for collaboration and learning across disciplines was highlighted in several challenges, e.g. to better understand and model complex ecological interactions between pathogens, vectors, wildlife hosts and livestock in the context of climate change. Collaboration between socio-economic and biophysical disciplines was seen as important for better engagement with stakeholders and for improved modelling of the costs and benefits of poor livestock health. The need for more comprehensive validation of empirical relationships, for harmonising terminology and measurements, and for building capacity for under-researched nations, systems and health problems indicated the importance of joined up approaches across nations. The challenges and priorities identified can help focus the development of modelling capacity and future research structures in this vital field. Well-funded networks capable of managing the long-term development of shared resources are required in order to create a cohesive modelling community equipped to tackle the complex challenges of climate change. [less ▲]

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