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Peer Reviewed
See detailGenetic parameters estimation for spirometric performances in Belgian Blue calves
Bureau, Fabrice ULg; Fievez, Laurence ULg; Michaux, C. et al

in Proceedings: 17th Symposium of the Comparative Respiratory Society (1999)

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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 detailGenetic parameters for individual weights at birth, weaning and 60 days of stress negative Piétrain pigs in the tropics: the case of Vietnam
Do Duc, Luc ULg; Michaux, Charles ULg; Dang Vu, Binh et al

Poster (2012, November 28)

Data recorded between 2008 and 2012 from Dong Hiep pig farm, Vietnam, was used to stimate genetic parameters for weights at birth (WB), weaning (WW) and 60 days (W60) of stress negative Piétrain pigs ... [more ▼]

Data recorded between 2008 and 2012 from Dong Hiep pig farm, Vietnam, was used to stimate genetic parameters for weights at birth (WB), weaning (WW) and 60 days (W60) of stress negative Piétrain pigs using restricted maximum likelihood methodology. WB, WW and W60 were recorded from 1146, 839 and 610 animals respectively. The data were analyzed according to a mixed model including 4 fixed effects, parity, season, sex, and interaction between halothane genotype and country of origin (Belgium and Vietnam) of sows. Additionally, 3 random effects (maternal common environment for litter, direct and maternal additive genetic) for WB and 2 random effects (maternal common environment for litter and direct additive genetic) for WW and W60 were included in the model. Estimates of direct heritability and proportion of the maternal common environmental variance for WB, WW and W60 were 0.20, 0.13; 0.22, 0.21 and 0.19, 0.30 respectively. In addition, the estimate of maternal heritability for WB was 0.14. These genetic parameters suggest that WB, WW and W60 could be improved by selection using both direct and maternal effects. [less ▲]

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See detailGenetic parameters for methane emission predicted from milk mid-infrared spectra in dairy cows
Kandel, Purna Bhadra ULg; Vanrobays, Marie-Laure ULg; Vanlierde, Amélie et al

in Advances in Animal Biosciences (2013)

N/A

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See detailGenetic parameters for methane emission predicted from milk mid-infrared spectra in dairy cows
Kandel, Purna Bhadra ULg; Vanrobays, Marie-Laure ULg; Vanlierde, Amélie et al

in Advances in Animal Biosciences (2013), 4(2),

N/A

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See detailGenetic parameters for methane emissions predicted from milk mid-infrared spectra in dairy cows
Kandel, Purna Bhadra ULg; Vanrobays, Marie-Laure ULg; Vanlierde, Amélie et al

in Journal of Dairy Science (2013), 95(E-1), 388

Genetic selection of low methane (CH4) emitting animals is additive and permanent but the difficulties associated with individual CH4 measurement result in a paucity of records required to estimate ... [more ▼]

Genetic selection of low methane (CH4) emitting animals is additive and permanent but the difficulties associated with individual CH4 measurement result in a paucity of records required to estimate genetic variability of CH4 traits. Recently, it was shown that direct quantification of CH4 emissions by mid-infrared spectroscopy (MIR) from milk. The CH4 prediction equation was developed using 452 SF6 CH4 measurements with associated milk spectra and the calibration equation was developed using PLS regression. The obtained SD of predicted CH4 was 126.39 g/day with standard error of cross validation 68.68 g/day and a cross-validation coefficient of determination equal to 70%. The equation was applied on a total of 338,917 spectra obtained from milk samples collected between January 2007 and August 2012 during the Walloon milk recording for first parity Holstein cows. The prediction of MIR CH4 was 547 ± 111 g/d and MIR CH4 g/kg of fat and protein corrected milk (FPCM) was 23.66 ± 8.21.Multi-trait random regression test-day models were used to estimate the genetic variability of MIR predicted CH4 and milk production traits. The heritability, phenotypic and genetic correlations between MIR predicted CH4 traits and milk traits are presented in Table 1. Estimated heritability for CH4 g/day and CH4 g/kg of FPCM were lower than common production traits but would still be useful in breeding programs. While selection for cows emitting lower amounts of MIR predicted CH4 (g/d) would have little effect on milk production traits, selection on MIR predicted CH4 (g/kg of FPCM) would decrease FPCM, fat and protein yields. These genetic parameters of CH4 indicator traits might be entry point for selection that accounts mitigation of CH4 from dairy farming. Table 1. Heritability (diagonal), phenotypic (below the diagonal) and genetic (above the diagonal) correlations between MIR predicted CH4 and production traits Traits MIR CH4 (g/d) MIR CH4 ((g/kg of FPCM) FPCM Fat yield Protein yield MIR CH4 (g/d) 0.11 0.42 0.03 0.19 0.04 MIR CH4 (g/kg of FPCM)0.59 0.18 -0.83 -0.72 -0.77 FPCM -0.02 -0.65 0.20 0.95 0.91 Fat yield 0.01 -0.58 0.76 0.22 0.70 Protein yield -0.01 -0.61 0.78 0.69 0.20 [less ▲]

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See detailGenetic parameters for methane emissions predicted from milk mid-infrared spectra in dairy cows
Kandel, Purna Bhadra ULg; Vanrobays, Marie-Laure ULg; vanlierde, Amélie et al

Scientific conference (2013, March 25)

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See detailGenetic parameters for methane indicator traits based on milk fatty acids
Kandel, Purna Bhadra ULg; Gengler, Nicolas ULg; Soyeurt, Hélène ULg

Scientific conference (2012, February 14)

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See detailGenetic parameters for methane indicator traits based on milk fatty acids in cows
Kandel, Purna Bhadra ULg; Vanlierde, Amélie; Dehareng, Frédéric et al

Conference (2012, July 18)

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See detailGenetic parameters for methane indicator traits based on milk fatty acids in cows
Kandel, Purna Bhadra ULg; Vanlierde, Amélie; Dehareng, Frédéric et al

in Journal of Dairy Science (2012, July 18)

Dairy production is pointed out for its large methane emission. Therefore, currently studies of factors affecting emission and methods to abate methane emission are numerous. However, an important issue ... [more ▼]

Dairy production is pointed out for its large methane emission. Therefore, currently studies of factors affecting emission and methods to abate methane emission are numerous. However, an important issue is the development of easily obtainable indicators, because they would also allow estimating animal genetic variability of methane emission. Recently methane indicators were proposed using gas chromatrography based milk fatty acid composition. We derived these published methane indicators using 1100 calibration samples directly from mid-infrared (MIR).For the published indicator showing the highest relationship (R2 = 0.88) with Sulfur Hexafluoride 6 methane emission data, genetic parameters for this MIR based indicator were estimated by single trait random regression test-day models from 619,272 records collected from 2007 to 2011 on 71,188 Holstein cows in their first three lactations at Walloon region of Belgium. The average daily heritability was 0.35±0.01, 0.35±0.02 and 0.32±0.02 for the first three lactations, respectively. Similarly, the lactation heritability was 0.67±0.02, 0.72±0.03 and 0.62±0.03. As expected, methane production was higher during the peak milk production depicting the normal lactation curve. The largest differences between estimated breeding values (EBV) of sires having cows in production eructing the highest and the lowest methane content was 21.80, 22.75 and 24.89 kg per lactation for the first three parities, the variances of the EBV of the sires with daughters were 10.67, 12.46, 12.18 kg2. Results were similar for other indicators. This study suggested that methane indicator traits can be predicted by MIR. Genetic parameters also indicated a rather high heritability and genetic variability exist for these published indicators and consequently a potential high genetic variability of methane eructation by dairy cows. Therefore, these first finding might open new opportunities for animal selection programs that include the reduction of methane emission. [less ▲]

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See detailGenetic parameters for methane indicator traits based on milk fatty acids in Dual Purpose Belgian Blue cattle
Kandel, Purna Bhadra ULg; Gengler, Nicolas ULg; Soyeurt, Hélène ULg

Poster (2012, June 18)

Dairy production is pointed out for its large methane emission. Therefore, specific nutritional strategies are applying to abate methane emission but very less information is available about the animal ... [more ▼]

Dairy production is pointed out for its large methane emission. Therefore, specific nutritional strategies are applying to abate methane emission but very less information is available about the animal genetic variability of methane emission. Methane indicators using traits indirectly related to methane and easily recorded like the mid-infrared (MIR) prediction of fatty acid could be used to conduct genetic studies. MIR methane indicators used in this study were derived from published fatty acid based methane indicators using 597 calibration samples. Genetic parameters of these MIR indicators were estimated by single trait random regression test-day models from 13,389 records collected on 1602 Dual Purpose Belgium Blue cows in their first 3 lactations. For the published indicator showing the highest relationship (R2 =0.88) with Sulphur hexafluoride (SF6) methane emission data, the average daily heritability was 0.25±0.06, 0.25±0.07 and 0.18±0.09 for the first three lactations, respectively. Similarly, the lactation heritability was 0.45±0.09, 0.46±0.11 and 0.24±0.14. The sire genetic variability was 3.60, 4.08, 1.19 kg2 of methane for the first three lactation, respectively. The genetic difference between the sires having cows eructing the highest and the lowest methane content was 11.62, 13.01 and 5.98 kg per lactation for the first three parities. This study suggested that methane indicator traits can be predicted by MIR and the genetic variability of these traits seems to exist. Therefore, it also suggests the genetic variability of methane content eructed by dairy cows. These first finding might open new opportunities for animal selection program on methane emission. [less ▲]

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See detailGenetic parameters for mid-infrared methane indicators based on milk fatty acids in dairy cows
Kandel, Purna Bhadra ULg; Gengler, Nicolas ULg; Soyeurt, Hélène ULg

in Journal of Applied Animal Research (in press)

Dairy production is identified as a major source of methane (CH4) emissions. Selective breeding canbe one method used to mitigate CH4 emissions but practical and cheap measurement of this trait is not ... [more ▼]

Dairy production is identified as a major source of methane (CH4) emissions. Selective breeding canbe one method used to mitigate CH4 emissions but practical and cheap measurement of this trait is not currently available. The mid-infrared (MIR) prediction of milk fatty acids is relevant in this context. Five MIR methane indicators were derived from the literature and were calibrated from 600 samples analyzed by gas chromatography. Genetic parameters for these traits were estimated using single trait random regression test-day models from 619,265 records collected from 2007 to 2011 on 71,188 Holstein cows in their first three lactations. For the published indicator showing the highest relationship with the methane data (R2 = 0.88), the average daily heritability was 0.34±0.01, 0.37±0.01 and 0.34±0.01 for the first three lactations, respectively. The methane emission (g/day) was increased from beginning of lactation, reached at the highest in peak of lactation and decreased towards end of lactation. The largest differences between estimated breeding values (EBV) of sires having daughters in production eructing the highest and the lowest methane content was 21.80, 22.75 and 24.89 kg per lactation for the first three parities. Positive genetic correlations were estimated between indicator traits and milk fat and protein content. Low negative correlation was observed with milk yield. In conclusion, this study shows the feasibility to predict methane indicator traits by MIR. Moreover, the estimated genetic parameters suggest also a potential genetic variability of the quantity of methane eructed by dairy cows. [less ▲]

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See detailGenetic parameters for Tunisian Holsteins using a test-day random regression model.
Hammami, Hedi ULg; Rekik, Boulbaba; Soyeurt, Hélène ULg et al

in Journal of Dairy Science (2008), 91(5), 2118-26

Genetic parameters of milk, fat, and protein yields were estimated in the first 3 lactations for registered Tunisian Holsteins. Data included 140,187; 97,404; and 62,221 test-day production records ... [more ▼]

Genetic parameters of milk, fat, and protein yields were estimated in the first 3 lactations for registered Tunisian Holsteins. Data included 140,187; 97,404; and 62,221 test-day production records collected on 22,538; 15,257; and 9,722 first-, second-, and third-parity cows, respectively. Records were of cows calving from 1992 to 2004 in 96 herds. (Co)variance components were estimated by Bayesian methods and a 3-trait-3-lactation random regression model. Gibbs sampling was used to obtain posterior distributions. The model included herd x test date, age x season of calving x stage of lactation [classes of 25 days in milk (DIM)], production sector x stage of lactation (classes of 5 DIM) as fixed effects, and random regression coefficients for additive genetic, permanent environmental, and herd-year of calving effects, which were defined as modified constant, linear, and quadratic Legendre coefficients. Heritability estimates for 305-d milk, fat and protein yields were moderate (0.12 to 0.18) and in the same range of parameters estimated in management systems with low to medium production levels. Heritabilities of test-day milk and protein yields for selected DIM were higher in the middle than at the beginning or the end of lactation. Inversely, heritabilities of fat yield were high at the peripheries of lactation. Genetic correlations among 305-d yield traits ranged from 0.50 to 0.86. The largest genetic correlation was observed between the first and second lactation, potentially due to the limited expression of genetic potential of superior cows in later lactations. Results suggested a lack of adaptation under the local management and climatic conditions. Results should be useful to implement a BLUP evaluation for the Tunisian cow population; however, results also indicated that further research focused on data quality might be needed. [less ▲]

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See detailGenetic Parameters of Butter Hardness Estimated by Test-Day Model
Soyeurt, Hélène ULg; Dehareng, Frédéric; Bertozzi, Carlo et al

in Interbull Bulletin (2007), 37

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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 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 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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Peer Reviewed
See detailGenetic parameters of racing performance traits of Arabian horses in Algeria
Tennah, Safia ULg; Kafidi, Nacereddine; Antoine-Moussiaux, Nicolas ULg et al

Poster (2013, October 11)

The data used in the present study were recorded at the Algerian Horse Racing Society for 36492 racing performance of 913 Arabian horses from 1995 to 2007. The aim of the study was to identify the genetic ... [more ▼]

The data used in the present study were recorded at the Algerian Horse Racing Society for 36492 racing performance of 913 Arabian horses from 1995 to 2007. The aim of the study was to identify the genetic parameters underlying three traits: two earnings traits, namely the logarithm of average annual virtual earnings (LAEV) and the logarithm of average annual virtual earnings per start (LAEV/S), and a ranking trait, the normalized ranking (PERF). To identify the fixed effects to be included in the genetic mixed model, a preliminary analysis was conducted using the General Linear Models (GLM) procedure from SAS software. The effects of age, sex, year and the interaction between year of the race and age and between sex and age were included in the model for the three traits. Afterwards, two random effects, a direct genetic effect of the animal and a permanent environmental effect were included in the mixed model. The variance components and genetic parameters were estimated using the restricted maximum likelihood (REML) procedure with the MTDFREML program. The analyses with this repeatable animal model led to the following estimation of the genetic parameters: for LAEV, heritability was 0.225 (±0.041), while estimate of repeatability was 0.330 (±0.040). For LAEV/S, heritability was 0.164 (±0.027), while estimate of repeatability was 0.215 (±0.022). The heritability for the normalized ranking was higher, 0.369 (±0.054), indicating that this trait might provide faster progress for breeding programs of Arabian horses in Algeria. The repeatability estimate for the normalized ranking was 0.587 (±0.045). The genetic correlation between LAEV and LAEV/S was 0.99, revealing a almost complete genetic dependence between these two traits, 0.69 between PERF and LAEV and 0.79 between PERF and LAEV/S. [less ▲]

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See detailGenetic parameters of saturated and monounsaturated fatty acid content and the ratio of saturated to unsaturated fatty acids in bovine milk.
Soyeurt, Hélène ULg; Dardenne, Pierre; Dehareng, Frédéric et al

in Journal of Dairy Science (2008), 91(9), 3611-26

Fatty acid composition influences the nutritional quality of milk and the technological properties of butter. Using a prediction of fatty acid (FA) contents by mid-infrared (MIR) spectrometry, a large ... [more ▼]

Fatty acid composition influences the nutritional quality of milk and the technological properties of butter. Using a prediction of fatty acid (FA) contents by mid-infrared (MIR) spectrometry, a large amount of data concerning the FA profile in bovine milk was collected. The large number of records permitted consideration of more complex models than those used in previous studies. The aim of the current study was to estimate the effects of season and stage of lactation as well as genetic parameters of saturated (SAT) and monounsaturated (MONO) fatty acid contents in bovine milk and milk fat, and the ratio of SAT to unsaturated fatty acids (UNSAT) that reflect the hardness of butter (SAT:UNSAT), using 7 multiple-trait, random-regression test-day models. The relationship between these FA traits with common production traits was also studied. The data set contained 100,841 test-day records of 11,626 Holstein primiparous cows. The seasonal effect was studied based on unadjusted means. These results confirmed that milk fat produced during spring and summer had greater UNSAT content compared with winter (63.13 vs. 68.94% of SAT in fat, on average). The effect of stage of lactation on FA profile was studied using the same methodology. Holstein cows in early first lactation produced a lower content of SAT in their milk fat. Variance components were estimated using a Bayesian method via Gibbs sampling. Heritability of SAT in milk (0.42) was greater than heritability of SAT in milk fat (0.24). Estimates of heritability for MONO were also different in milk and fat (0.14 vs. 0.27). Heritability of SAT:UNSAT was moderate (0.27). For all of these traits, the heritability estimates and the genetic and phenotypic correlations varied through the lactation. [less ▲]

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