References of "Gillon, Alain"
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See detailAdding value to test-day data by using modified best prediction method
Gillon, Alain ULg; Abras, Sven; Mayeres, Patrick et al

in ICAR Technical Series (2010, November), 14

Computation of lactation yields from test-day data has lost much of its importance for genetic evaluations as the use of test-day models is currently quite widespread. In the other hand its interest for ... [more ▼]

Computation of lactation yields from test-day data has lost much of its importance for genetic evaluations as the use of test-day models is currently quite widespread. In the other hand its interest for intra-farm management is increasing as a base for advanced management tools. The first and principal aim of this study was to develop a method which takes into account advantages and disadvantages of existing methods, and to test its potential to provide useful management tools to dairy farmers. A test-day model with modifications to able daily run and management tools was developed. Because of its similarities with best prediction, the method developed here was called modified best prediction. The second objective was to compare the accuracy of this new method with best prediction and test interval methods. Modified best prediction showed good results for predicting daily yields and was slightly better than best prediction for lactation yields prediction. Management tools obtained with modified best prediction are explained. [less ▲]

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See detailGenetic parameters of mastitis-correlated milk components in first parity dairy cows
Gillon, Alain ULg; Bastin, Catherine ULg; Soyeurt, Hélène ULg et al

Conference (2010, August 06)

Ind. of lactoferrin content, ind. of Na content, and lactose content were the three most correlated milk components with somatic cell score among available milk components predicted by mid-infrared ... [more ▼]

Ind. of lactoferrin content, ind. of Na content, and lactose content were the three most correlated milk components with somatic cell score among available milk components predicted by mid-infrared spectrometry on 590,083 test-day records from Walloon Region of Belgium collected between 2007 and 2009. Mean daily heritabilities and mean genetic correlations of these four traits were estimated using Gibbs sampling methodology applied to a multi-trait random regression test-day model with a subset of these records. Mean daily heritabilities of ind. lactoferrin content (0.34), ind. Na content (0.37) and lactose content (0.42) were higher then SCS (0.16) and mean genetic correlations were moderate (from -0.18 to -0.73), showing that these traits could be used together to describe udder health in genetic evaluations instead of SCS alone when clinical mastitis data are not available. [less ▲]

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

Poster (2010, August 02)

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

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

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See detailGenetic correlations among body condition score, yield and fertility in multiparous cows using random regression models
Bastin, Catherine ULg; Gillon, Alain ULg; Massart, Xavier et al

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

Genetic correlations between body condition score (BCS) in lactation 1 to 3 and four economically important traits (days open, 305-days milk, fat, and protein yields recorded in the first 3 lactations ... [more ▼]

Genetic correlations between body condition score (BCS) in lactation 1 to 3 and four economically important traits (days open, 305-days milk, fat, and protein yields recorded in the first 3 lactations) were estimated on about 12,500 Walloon Holstein cows using 4-trait random regression models. Results indicated moderate favorable genetic correlations between BCS and days open (from -0.46 to -0.62) and suggested the use of BCS for indirect selection on fertility. However, unfavorable genetic correlations between BCS and yields (from -0.16 to -0.71) indicated that selection on BCS would have deleterious effects on milk, fat, and protein yields, especially in lactation greater than 1. [less ▲]

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See detailGenetic parameters of mastitis-correlated milk components in first parity dairy cows
Gillon, Alain ULg; Bastin, Catherine ULg; Soyeurt, Hélène ULg et al

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

Ind. of lactoferrin content, ind. of Na content, and lactose content were the three most correlated milk components with somatic cell score among available milk components predicted by mid-infrared ... [more ▼]

Ind. of lactoferrin content, ind. of Na content, and lactose content were the three most correlated milk components with somatic cell score among available milk components predicted by mid-infrared spectrometry on 590,083 test-day records from Walloon Region of Belgium collected between 2007 and 2009. Mean daily heritabilities and mean genetic correlations of these four traits were estimated using Gibbs sampling methodology applied to a multi-trait random regression test-day model with a subset of these records. Mean daily heritabilities of ind. lactoferrin content (0.34), ind. Na content (0.37) and lactose content (0.42) were higher then SCS (0.16) and mean genetic correlations were moderate (from -0.18 to -0.73), showing that these traits could be used together to describe udder health in genetic evaluations instead of SCS alone when clinical mastitis data are not available. [less ▲]

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See detailAdding value to test-day data by using modified best prediction method
Gillon, Alain ULg; Abras, Sven; Mayeres, Patrick et al

Conference (2010, June 04)

Computation of lactation yields from test-day data has lost much of its importance for genetic evaluations as the use of test-day models is currently quite widespread. In the other hand its interest for ... [more ▼]

Computation of lactation yields from test-day data has lost much of its importance for genetic evaluations as the use of test-day models is currently quite widespread. In the other hand its interest for intra-farm management is increasing as a base for advanced management tools. The first and principal aim of this study was to develop a method which takes into account advantages and disadvantages of existing methods, and to test its potential to provide useful management tools to dairy farmers. A test-day model with modifications to able daily run and management tools was developed. Because of its similarities with best prediction, the method developed here was called modified best prediction. The second objective was to compare the accuracy of this new method with best prediction and test interval methods. Modified best prediction showed good results for predicting daily yields and was slightly better than best prediction for lactation yields prediction. Management tools obtained with modified best prediction are explained. [less ▲]

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See detailGenetic evaluation for body condition score in the Walloon Region of Belgium
Bastin, Catherine ULg; Gillon, Alain ULg; Massart, Xavier et al

Conference (2010, June 02)

Detailed reference viewed: 26 (8 ULg)
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See detailGenetic evaluation for body condition score in the Walloon region of Belgium
Bastin, Catherine ULg; Gillon, Alain ULg; Massart, Xavier et al

in Interbull Bulletin (2010), 42

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See detailAssociations among BCS, milk production and days-open in Walloon primiparous dairy cows
Massart, Xavier; Laloux, Laurent; Bastin, Catherine ULg et al

Conference (2009, August 27)

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See detailAdding value to test-day data by using modified best prediction method
Gillon, Alain ULg; Abras, Sven; Mayeres, Patrick et al

in Book of Abstracts of the 60th Annual Meeting of the European Association for Animal Production (2009, August)

Computation of lactation yields from test-day yield has lost much of its importance for genetic evaluations as <br />the use of test-day models is rather widespread. At the same time its importance for ... [more ▼]

Computation of lactation yields from test-day yield has lost much of its importance for genetic evaluations as <br />the use of test-day models is rather widespread. At the same time its importance for intra-farm management <br />increases at farms as a base for advanced management tools. The most common official method to compute <br />lactation yield is the Test Interval Method (TIM). Alternative methods for computing cumulated productions <br />were developed. These methods can be considered as improvements of TIM as the interpolation method, <br />or completely different methods as multiple-trait prediction (MTP) and best prediction (BP). Research <br />in this field has shown the potential to compute lactation parameters (e.g., cumulated production) with <br />test-day models. The aim of this study was to develop a new method which takes into account advantages <br />and disadvantages of existing methods, and to test its potential to provide useful tools to help farmers to <br />make management decisions. The second objective was to compare the accuracy and the robustness of this <br />method with those of BP and TIM. Because of its similarities with BP, the method developed here was <br />called mBP, for modified-BP. The main difference from BP is the definition of the standard lactation curve. <br />To minimize bias, components of standard lactation curves proper to each herd are computed jointly with <br />random individual effects. Recently a new version of mBP was tested that puts expectations of constant <br />animal effects to observed average values using Bayesian prediction, a feature also used by MTP. [less ▲]

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See detailAssociations among BCS, milk production and days-open in Walloon primiparous dairy cows
Laloux, Laurent; Bastin, Catherine ULg; Gillon, Alain ULg et al

in Book of abstracts of the 60th annual meeting of the European Association for Animal Production (2009, August)

Detailed reference viewed: 31 (11 ULg)
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See detailLe BCS, une méthode simple à la source de conseils variés : ration, repro et santé
Laloux, Laurent; Bastin, Catherine ULg; Gillon, Alain ULg et al

Poster (2009, February 11)

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See detailModeling milk urea of Walloon dairy cows in management perspectives.
Bastin, Catherine ULg; Laloux, Laurent; Gillon, Alain ULg et al

in Journal of Dairy Science (2009), 92(7), 3529-40

The aim of this study was to develop an adapted random regression test-day model for milk urea (MU) and to study the possibility of using predictions and solutions given by the model for management ... [more ▼]

The aim of this study was to develop an adapted random regression test-day model for milk urea (MU) and to study the possibility of using predictions and solutions given by the model for management purposes. Data included 607,416 MU test-day records of first-lactation cows from 632 dairy herds in the Walloon Region of Belgium. Several advanced features were used. First, to detect the herd influence, the classical herd x test-day effect was split into 3 new effects: a fixed herd x year effect, a fixed herd x month-period effect, and a random herd test-day effect. A fixed time period regression was added in the model to take into account the yearly oscillations of MU on a population scale. Moreover, first autoregressive processes were introduced and allowed us to consider the link between successive test-day records. The variance component estimation indicated that large variance was associated with the random herd x test-day effect (48% of the total variance), suggesting the strong influence of herd management on the MU level. The heritability estimate was 0.13. By comparing observed and predicted MU levels at both the individual and herd levels, target ranges for MU concentrations were defined to take into account features of each cow and each herd. At the cow level, an MU record was considered as deviant if it was <200 or >400 mg/L (target range used in the field) and if the prediction error was >50 mg/L (indicating a significant deviation from the expected level). Approximately 7.5% of the MU records collected between June 2007 and May 2008 were beyond these thresholds. This combination allowed for the detection of potentially suspicious cows. At the herd level, the expected MU level was considered as the sum of the solutions for specific herd effects. A herd was considered as deviant from its target range when the prediction error was greater than the standard deviation of MU averaged by herd test day. Results showed that 6.7% of the herd test-day MU levels between June 2007 and May 2008 were considered deviant. These deviations seemed to occur more often during the grazing period. Although theoretical considerations developed in this study should be validated in the field, this research showed the potential use of a test-day model for analyzing functional traits to advise dairy farmers. [less ▲]

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