References of "Arnould, Valérie"
     in
Bookmark and Share    
Full Text
Peer Reviewed
See detailEstimating daily yield and content of major fatty acids from single milking
Arnould, Valérie ULg; Reding, Romain; Delvaux, Charles et al

Poster (2014, February 07)

Reducing the frequency of milk recording and the number of recorded samples per test-day could be a solution in order to reduce costs of official milk recording. However, fewer samples lead to a decrease ... [more ▼]

Reducing the frequency of milk recording and the number of recorded samples per test-day could be a solution in order to reduce costs of official milk recording. However, fewer samples lead to a decrease in the accuracy of predicted daily yields. Unfortunately, the current published equations use the milking interval that is often not available and/or reliable in practice. The first objective of this study was to propose models using easily available traits. Therefore the milking interval was replaced by a combination of data easily recorded by milk recording. The second objective of this study was to enlarge the previous investigations to milk fatty acids (FA) in order to propose a practical method for estimating accurate daily milk, fat and major FA yields from single milking. The fit goodness of proposed models was evaluated based on the correlation values between the estimated and observed daily yields in addition to the calculation of the mean square error. Obtained results are promising. Correlation values were comprised between 96.4% and 97.6% when daily yield were estimated from morning milking, and from 96.9% to 98.3% when daily yield were estimated from evening milking. The combination of records related to lactation stage, month of test, milk yield, and fat could replace the milking interval effect. Because of their simplicity, proposed models would be easy to implement. [less ▲]

Detailed reference viewed: 29 (8 ULg)
Full Text
See detailAktueller Stand der Projekte QuaM, ManageMilk und OptiMir (Erste Ergebnisse sind vielversprechend)
Reding, Romain; Arnould, Valérie ULg

Article for general public (2013)

Detailed reference viewed: 23 (6 ULg)
Full Text
See detailNeuartige Management Tools für Milchviehbetrieb mittels Spektralanalytik
Arnould, Valérie ULg; Reding, Romain; Bormann, Jeanne et al

Article for general public (2013)

In den letzten Jahrzenten wurde die Milch- und Fleischproduktion mehr und mehr mit generellen Nachhaltigkeitsfragen in Verbindung gebracht. Sehr oft wird eine bessere Produktionsnachhaltigkeit auch mit ... [more ▼]

In den letzten Jahrzenten wurde die Milch- und Fleischproduktion mehr und mehr mit generellen Nachhaltigkeitsfragen in Verbindung gebracht. Sehr oft wird eine bessere Produktionsnachhaltigkeit auch mit ökonomischen Aspekten verbunden. In der Tat liegt die Kunst der modernen Milchproduktion scheinbar vor allem darin, die Produktion (egal ob tier- oder betriebsindividuell) stetig bei möglichst gleichbleibenden oder gar noch geringeren Kosten zu erhöhen. Daneben ist zu bedenken, dass Konsumenten heutzutage neben preislichen Aspekten sehr oft zusätzlich Gesundheitsaspekte ins Spiel bringen, so dass es für Milchbetriebe nicht unwesentlich ist, die Produktion in gewisser Weise diesen Ansprüchen nach zu gestalten. Glücklicherweise können entscheidende Inhaltsstoffe wie der Milchfettgehalt oder das Fettsäuremuster der Milch durch Managementfaktoren wie Zucht, Selektion, Fütterung und Haltungsbedingungen zum Positiven beeinflusst werden und den Anforderungen der Nachfrageseite besser angepasst werden. Genau bei dieser Problematik liegen die Ansatzpunkte der verschiedenen CONVIS Projekte (QuaM, ManageMILK und OptiMIR) im Bereich Spektralanalysen der Milch. [less ▲]

Detailed reference viewed: 40 (15 ULg)
Full Text
Peer Reviewed
See detailReview: Milk composition as management tool of sustainability
Arnould, Valérie ULg; Reding, Romain; Bormann, Jeanne et al

in Biotechnologie, Agronomie, Société et Environnement = Biotechnology, Agronomy, Society and Environment [=BASE] (2013), 17(4), 613-621

The main objective of this paper is the use of milk composition data as a management tool. Milk composition, and in particular, milk fat content and fatty acid profiles may be significantly altered due to ... [more ▼]

The main objective of this paper is the use of milk composition data as a management tool. Milk composition, and in particular, milk fat content and fatty acid profiles may be significantly altered due to a variety of factors. These factors are reviewed in the literature; they include diet, animal (genetic) selection, management aspects and animal health. Changes in milk composition can be used as an indicator of the animal’s metabolic status or the efficiency of the feed management system. The advantages of using this kind of data as a management tool would be to allow the early detection of metabolic or management problems. The present review suggests that milk and, especially milk fat composition may be used as a sustainability management tool and as a monitoring and prevention tool for several pathologies or health disorders in dairy cattle. Further, due to the use of MIR technology, these tools may be easily implemented in practice and are relatively cheap. In the field, milk labs or milk recording agencies would be able to alert farmers whenever threshold values for disease were reached, allowing them to improve their dairy production from an economic, ecological and animal (welfare) point of view. [less ▲]

Detailed reference viewed: 64 (25 ULg)
Full Text
Peer Reviewed
See detailEffect of milk recording schemes on milk and milk components genetic parameters in Luxembourg
Arnould, Valérie ULg; Gengler, Nicolas ULg; Soyeurt, Hélène ULg

Conference (2012, July 18)

A particularity of the Luxembourg milk recording is the use of different schemes. Two principal schemes are applied: the scheme “S” applied on 69.1% of the total herds (n=712) and consisting in one ... [more ▼]

A particularity of the Luxembourg milk recording is the use of different schemes. Two principal schemes are applied: the scheme “S” applied on 69.1% of the total herds (n=712) and consisting in one proportionate sample of all daily milkings, and the scheme “T” (21.6% of the total herds) which consists in one sample of only one milking (morning or evening milking) (and alternating milking time from month to month). The problematic is that application of different schemes could influence the milk components (protein and fat yield) and the milk fat components (saturated and unsaturated groups of fatty acids) genetic parameters estimation and to prevent all comparisons between dairy population under different milk recording schemes. A total of 47,613 and 44,833 test-day records were obtained, respectively for schemes “S” and “T” from Holstein cows in first lactation in Luxembourg dairy herds. The used model included as fixed effects: herd x date of test, class of age, and month x year. Random effects were permanent environmental, additive genetics, and residual effects. The main objective of this work is to study the effect the choice of milk recording schemes (“S” or “T” schemes) on milk yield and milk components genetic parameters. A solution could be to add a fixed effect taking in account the milking time. The second objective is to study the effect of milking time (morning or evening) on genetic parameters estimated in the case of scheme “T”. According to the results, genetic parameters were statistically different between the schemes “S” and “T” for milk yield (P value < 0.0001). Further, the classifications of bulls according to their breeding values were very different when values were estimated on basis of scheme “S” or “T” (Spearman correlation value of 0.51 for milk yield for example). In conclusion, using several milk recording schemes do not allow any comparison of genetic parameters between dairy cattle’s. [less ▲]

Detailed reference viewed: 47 (20 ULg)
Full Text
See detailFeasibility of genomic prediction of fatty acids composition in milk of dairy cattle from Luxembourg using single-step procedure
Faux, Pierre ULg; Arnould, Valérie ULg; Soyeurt, Hélène ULg et al

Conference (2012, July 16)

Milk composition in fatty acids (FA) portrays a class of novel traits of interest for both human health and animal robustness. With the exception of Wallonia, Luxembourg is currently the only place in the ... [more ▼]

Milk composition in fatty acids (FA) portrays a class of novel traits of interest for both human health and animal robustness. With the exception of Wallonia, Luxembourg is currently the only place in the world where, using mid-infrared spectrometry, milk composition in 29 FA is routinely recorded for dairy cows. Since 2007, spectral data has been recorded so far on 87,368 cows from 690 different herds, by 2 main control methods (T-method: one sample of only one milking, morning or evening, and S-method: proportionate sample of all daily milkings). Additionally, milk, fat and protein yields are available since 1990. The availability of FA allows many options for management use and animal breeding but requires advanced modeling (e.g., adapted to the testing methods). In the context of animal breeding, genomic selection has been widely developed in dairy cattle, where single-step approach (ssGBLUP) is particularly well suited for small-sized populations, as the dairy cattle population of Luxembourg (365,892 animals currently in pedigree) and is completely integrated into mixed modeling of phenotypic data. The objectives of this study were: (1) to assess the potential benefits of a single-step genomic evaluation on milk FA composition in a small-sized population and in particular (2) to quantify the impact of genomic information on reliability (REL) of estimated breeding values (EBV) of FA in Luxembourg. In a preliminary study for a single FA, oleic acid (C18:1 cis 9) genetic evaluations were performed on 47,613 milk records; collected by S-method, from 8,000 cows in first parity with a random regression test-day model using second order Legendre polynomials. For this sample, molecular data was simulated for 422 AI sires, ancestors of recorded cows. Prediction error variances (PEV) were used to compute REL and effective daughter contributions (EDC). First results showed a low increase in REL and EDC. Extension of this research to all sampling methods and research on the optimum structure of the reference population (bulls, cows) will be done to fit the Luxembourg-specific situation. [less ▲]

Detailed reference viewed: 33 (10 ULg)
Full Text
Peer Reviewed
See detailEffect of the milk recording time on the genetic parameters of milk production and mid-infrared milk components in Luxembourg dairy cattle
Arnould, Valérie ULg; Gengler, Nicolas ULg; Soyeurt, Hélène ULg

in Journal of Dairy Science (2012, July), 95

A particularity of the Luxembourg milk recording is the use of different schemes. Two principal schemes are applied: the scheme “S” applied on 69.1% of the total herds (n=712) and consisting in one ... [more ▼]

A particularity of the Luxembourg milk recording is the use of different schemes. Two principal schemes are applied: the scheme “S” applied on 69.1% of the total herds (n=712) and consisting in one proportionate sample of all daily milkings, and the scheme “T” (21.6% of the total herds) which consists in one sample of only one milking (morning or evening milking) (and alternating milking time from month to month). The problematic is that application of different schemes could influence the milk components (protein and fat yield) and the milk fat components (saturated and unsaturated groups of fatty acids) genetic parameters estimation and to prevent all comparisons between dairy population under different milk recording schemes. A total of 47,613 and 44,833 test-day records were obtained, respectively for schemes “S” and “T” from Holstein cows in first lactation in Luxembourg dairy herds. The used model included as fixed effects: herd x date of test, class of age, and month x year. Random effects were permanent environmental, additive genetics, and residual effects. The main objective of this work is to study the effect the choice of milk recording schemes (“S” or “T” schemes) on milk yield and milk components genetic parameters. A solution could be to add a fixed effect taking in account the milking time. The second objective is to study the effect of milking time (morning or evening) on genetic parameters estimated in the case of scheme “T”. According to the results, genetic parameters were statistically different between the schemes “S” and “T” for milk yield (P value < 0.0001). Further, the classifications of bulls according to their breeding values were very different when values were estimated on basis of scheme “S” or “T” (Spearman correlation value of 0.51 for milk yield for example). In conclusion, using several milk recording schemes do not allow any comparison of genetic parameters between dairy cattle’s. [less ▲]

Detailed reference viewed: 104 (17 ULg)
Full Text
See detailVariability among morning and evening milk compositions during the lactation
Arnould, Valérie ULg; Gengler, Nicolas ULg; Soyeurt, Hélène ULg

Poster (2012, February 10)

The main objective of this study was to analyze milking-to-milking variability of milk yield and milk composition (such as fat and protein percentages and somatic cell count). Additional objective was to ... [more ▼]

The main objective of this study was to analyze milking-to-milking variability of milk yield and milk composition (such as fat and protein percentages and somatic cell count). Additional objective was to extend this analyze to the milk fat composition. Milk samples (n=195.960) were collected from 29.636 cows in 491 Luxembourg farms and analyzed by MIR spectrometry. The milk contents of saturated, mono-, poly- and unsaturated fatty acids, and short, medium and long chain fatty acids were predicted from the recorded MIR spectral data. As expected, the milk composition and the milk fat composition, are affected by several factors as the milking period and the days in milk. In practice, using separately milk evening and milk morning could be interesting for cheese or butter production. [less ▲]

Detailed reference viewed: 66 (26 ULg)
Full Text
See detailGenetic variation in heat stress tolerance of Holsteins producing under a continental temperate environment
Hammami, Hedi ULg; Arnould, Valérie ULg; Bormann, Jeanne et al

Poster (2012)

Under projected climate changes, considerations for heat stress tolerance but also for genotype by environment interactions should enter breeding decisions, both for importing, but also exporting ... [more ▼]

Under projected climate changes, considerations for heat stress tolerance but also for genotype by environment interactions should enter breeding decisions, both for importing, but also exporting countries. Most studies concerning the breeding strategies on heat stress tolerance used the temperature humidity index (THI) to assess the thermal stress in a given environment and assumed a specific threshold to each studied population with the same response to each individual above this threshold. Recently new comprehensive thermal indices (TI) integrating radiation solar, wind speed, in addition to temperature and relative humidity were developed. Therefore, the aim of this study is advanced modelling of milk yield trait to evaluate the genetic variation in heat stress tolerance of Holsteins in a temperate environment using random regressions models and six new comprehensive TI. A total of 107,350 test day milk records were available for 12,099 primiparous Holsteins calving from 2000 to 2010. Test-day milk records were merged with meteorological data from 14 public weather stations across Luxembourg. Daily values of 6 new comprehensive TI (3 THI and 3 apparent temperature indices) were calculated by averaging hourly TI over 24 hours. The average distance between herds and their meteorological reference station was of 16 km. Sensitivity of cows to the climate environmental conditions was modelled by applying a reaction norm for each animal, representing its EBV for milk yield on values of the TI on the day in milk (DIM). Six separate random regression models were applied using time-dependent (DIM) and specific TI-dependent covariates. Random effects were additive genetic, permanent environmental, and herd year modelled with Legendre polynomials of order 2 for both DIM and TI. Genetic variances of the different TI evaluated in this study represent 27 to 30% of their correspondent variances for DIM effect. Permanent environmental and genetic variances of TI effect were in the same range. Additive genetic variances and heritabilities for daily milk yield slightly decreased with increasing degrees of the different THI and apparent temperature indices. The average daily milk heritability overall the lactation at the mean of each of the six TI was of 0.28. Genetic correlations between adjacent points across the lactation were > 0.90. Correlations between extreme distant DIM (e.g. early and late lactation stage) were reduced at 0.38 to 0.52. The overall genetic correlations between the different values of each TI remain high (> 0.85). EBV’s summing regular additive effect (DIM effect) and tolerance to heat stress (TI effect) were computed for several combinations of DIM and TI values. Ranking for sires and cows did not change among the 6 heat stress indicators. The correlations between EBVs estimated with the six models were greater than 0.90. In conclusion, the different models depicted genetic variation of milk yield among combinations of DIM and TI levels without defining thresholds in advance. Genetic variation was slightly lower when TI values exceed the thermoneutral zone. Breeding for reduced thermal sensitivity using any of the six indicators of heat stress evaluated in this study is possible. The indicator TI2 representing the adjusted THI for radiation solar and wind speed is favoured because it was the indicator that did identify the highest yearly milk losses under this continental temperate environment. [less ▲]

Detailed reference viewed: 104 (18 ULg)
See detailPrediction of cow pregnancy status using conventional and novel mid-infrared predicted milk traits
Hammami, Hedi ULg; Bastin, Catherine ULg; Gillon, Alain et al

in Book of Abstracts of the 62nd Annual Meeting of the European Association for Animal Production (2011, August)

The objective of this study was to determine the ability of conventional milk cow characteristics and novel traits predicted by mid infrared (MIR) obtained from milk recording to predict the pregnancy ... [more ▼]

The objective of this study was to determine the ability of conventional milk cow characteristics and novel traits predicted by mid infrared (MIR) obtained from milk recording to predict the pregnancy status once the cow was inseminated. Conventional milk recording, spectral, and reproductive data collected in Luxembourg Hoslteins between 2008 and 2010 were used. Cows were defined as pregnant if they were positively checked and calved between 267 and 295 d later after the last AI or if they had calved between the later intervals when no checks were recorded. Pregnant or not within 3 intervals after last AI (<=35 d, 45-60 d, and 60-90 d) was modeled using logistic regression models firstly as a function of conventional cow milk characteristics and extended to fatty acids as novel traits predicted by MIR in a second step. The lactation curve characteristics for milk, fat, protein, and lactose yields were estimated using modified best prediction method. Test-day fatty acid contents were estimated from collected MIR spectra using an appropriate calibration equation. Two third proportion and one third of the whole data set were randomly selected for calibration and validation models respectively. The relation between the predicted and observed probabilities of cow pregnancy was approximately linear for calibration and validation models. The sensitivity-specificity combination for cow pregnancy increased when fatty acids were added to conventional milk characteristics as inputs to the different models (from 78 to 85% for sensitivity and from 40 to 52% for specificity). Results based on those models showed that it would be possible to help breeders to manage cow fertility using such tool implemented in the milk recording organizations. [less ▲]

Detailed reference viewed: 53 (20 ULg)
Full Text
Peer Reviewed
See detailEstimating daily yield and content of major fatty acids from single milking: First approach
Arnould, Valérie ULg; Froidmont, Eric; Nguyen, Nam et al

Poster (2011, July 11)

Detailed reference viewed: 33 (17 ULg)
Full Text
Peer Reviewed
See detailEstimating daily yield of major fatty acids from single milking: first approach.
Arnould, Valérie ULg; NGuyen, N. H.; Froidmont et al

in Journal of Dairy Science (2011, July), 94(E-Suppl. 1), 29

Reducing the frequency of milk recording and the number of recorded samples per test-day could be a solution in order to reduce costs of milk recording. However, this solution leads to decrease also the ... [more ▼]

Reducing the frequency of milk recording and the number of recorded samples per test-day could be a solution in order to reduce costs of milk recording. However, this solution leads to decrease also the accuracy of predicting daily yield. According to the literature, several authors have already worked on this problematic. Unfortunately, some effects used in previous studies are not often available or reliable in used databases. This study was aimed to enlarge these investigations to milk fatty acids (FA) production: saturated FA, mono-unsaturated FA, unsaturated FA, medium-chain FA, and long chain FA and to propose a simple, robust and practical method for estimating accurate daily major FA yield from single milking. To do this, five dairy cows were followed between January 2007 and December 2010. FA contents were predicted by mid-infrared spectrometry. The final database contained 1,440 records. The first step was to ensure that used effects were available in most used databases. According to the availability of data, height models were tested to estimate daily yields from both morning and evening milking. These models were compared on the basis of the coefficient of determination values between estimated and observed daily yields and the mean square error. The proposed models included progressively several effects such as the milk yield, the fat and protein content, some classes of stage in lactation, of month of test or of month of calving. As expected, R² values were higher when these effects are introduced in the model and were comprised between 0.87 and 0.88 when daily yield were estimated from morning milking, and from 0.75 and 0.86 when daily yield were estimated from evening milking. It was concluded that the introduction of these effects did highly improve the daily predictability of all trait yield and can partially replace the milking interval effect. It was also observed that daily yields estimated from evening milkings are less accurate than those estimated from morning milkings. Finally, the applied model will depend on the availability of the data and to the convenience of the applied model to the studied population. Keywords: Milk recording, Fatty acids, prediction [less ▲]

Detailed reference viewed: 43 (13 ULg)
Full Text
See detailEstimation de la quantité journalière grasse du lait à partir d'une seule traite (matin ou soir) des composés fins de la matière grasse du lait
Arnould, Valérie ULg; Froidmont, Eric; Nguyen, Nam et al

in 16ième Carrefour des Productions animales: la filière laitière bovine européenne est-elle durable? (2011, March 02)

Detailed reference viewed: 25 (9 ULg)
Full Text
See detailManageMilk - Création d'outils de management innovatifs et pratiques en vue d'améliorer la durabilité de la production laitière et de la qualité des produits laitiers: présentation du projet.
Arnould, Valérie ULg; Soyeurt, Hélène ULg; Stoll, Jean et al

in 16ième Carrefour des Prodcutions animales: La filière laitière bovine européenne est-elle durable? (2011, March 02)

Detailed reference viewed: 46 (13 ULg)
Full Text
See detailMid-infrared predictions of lactoferrin content in bovine milk
Soyeurt, Hélène ULg; Bastin, Catherine ULg; Colinet, Frédéric ULg et al

in Journal of Dairy Science (2011), 94(E-suppl.1), 714

Lactoferrin (LF) is a glycoprotein present in milk and active in the immune system of cows and humans. Therefore, an inexpensive and rapid analysis to quantify this protein is desirable. A previous study ... [more ▼]

Lactoferrin (LF) is a glycoprotein present in milk and active in the immune system of cows and humans. Therefore, an inexpensive and rapid analysis to quantify this protein is desirable. A previous study reported the potential to quantify LF from the mid-infrared (MIR) spectrometry from 69 milk samples. Through the European RobustMilk project (www.robustmilk.eu), 3,606 milk samples were collected in Belgium, Ireland, and Scotland from individual cows and analyzed using a MIR MilkoScanFT6000 spectrometer. Milk LF content was quantified using ELISA in duplicate. Average ELISA data with a CV lower than 5% were used. After the detection of spectral and ELISA outliers, the calibration set contained 2,499 samples. An equation to predict LF content from MIR was developed using partial least squared regression. A first derivative pre-treatment of spectra was used to correct the baseline drift. To improve the repeatability of the spectral data, a file which contained the spectra of samples analyzed on 5 spectrometers was used during the calibration. The lactoferrin mean was 159.28 mg/l of milk with a SD of 97.21 mg/l of milk. The calibration (C) coefficient of determination (R2) was equal to 0.73 with a standard error (SE) of calibration of 50.54 mg/l of milk. A cross-validation (CV) was used to assess the robustness of the equation. R2 CV was 0.72 with a SE-CV of 51.16 mg/l of milk. An external validation (V) was conducted on 150 milk samples collected in Belgium. The SE of prediction (SEP) was 59.17 mg/L of milk. The similarity between R2 C and R2CV as well as between SE-C and SE-CV and between SE-CV and SEP confirms the equations developed are robust. The correlation between predicted and measured LF values was 0.71. This lower value compared with the one obtained from the calibration set (0.85) could be explained by the low ELISA reproducibility (16.24% ± 25.51%). If the developed equation is used to clean the validation data set, a total of 16 samples can be deleted. The validation coefficient for these 134 samples increased to 0.82. From these results, the developed equation could be used for screening the dairy cow population for breeding purposes. [less ▲]

Detailed reference viewed: 73 (20 ULg)