International genomic co-operation; Who, what, when, where, why and how?

in Interbull Bulletin (2010), 42

Genetic evaluation for body condition score in the Walloon region of Belgium

in Interbull Bulletin (2010), 42

New Method to Combine Pedigree and Molecular Relationships applied to Brandrood Cattle

in 9th World Congress of Genetics Applied to Livestock Production: Leipzig, Germany (2010)

Relationship coefficients are traditionally based on pedigree data. Today, they are often replaced by coefficients calculated from molecular data, for example, microsatellites-based relationships for bio ... [more ▼]

Relationship coefficients are traditionally based on pedigree data. Today, they are often replaced by coefficients calculated from molecular data, for example, microsatellites-based relationships for bio-diversity studies or genomic relationships for prediction of breeding values. However, in many situations, optimal combination of both sources would be the best solutions; i.e. when population is incompletely genotyped or when pedigree information is sparse. Also even dense markers do not reflect the whole genome. The objective of this study was to applied a new method to calculate a relationship matrix by the combination of molecular and pedigree data on Brandrood cattle. The results showed that combining marker and pedigree information produced more accurate A-matrices what will be useful for future management of the breed genetic variability. [less ▲]

Genetic relationships between body condition score and reproduction traits in Canadian Holstein and Ayrshire first-parity cows.

in Journal of Dairy Science (2010), 93(5), 2215-28

The objective of this study was to investigate the genetic relationship between body condition score (BCS) and reproduction traits for first-parity Canadian Ayrshire and Holstein cows. Body condition ... [more ▼]

The objective of this study was to investigate the genetic relationship between body condition score (BCS) and reproduction traits for first-parity Canadian Ayrshire and Holstein cows. Body condition scores were collected by field staff several times over the lactation in herds from Quebec, and reproduction records (including both fertility and calving traits) were extracted from the official database used for the Canadian genetic evaluation of those herds. For each breed, six 2-trait animal models were run; they included random regressions that allowed the estimation of genetic correlations between BCS over the lactation and reproduction traits that are measured as a single lactation record. Analyses were undertaken on data from 108 Ayrshire herds and 342 Holstein herds. Average daily heritabilities of BCS were close to 0.13 for both breeds; these relatively low estimates might be explained by the high variability among herds and BCS evaluators. Genetic correlations between BCS and interval fertility traits (days from calving to first service, days from first service to conception, and days open) were negative and ranged between -0.77 and -0.58 for Ayrshire and between -0.31 and -0.03 for Holstein. Genetic correlations between BCS and 56-d nonreturn rate at first insemination were positive and moderate. The trends of these genetic correlations over the lactation suggest that a genetically low BCS in early lactation would increase the number of days that the primiparous cow was not pregnant and would decrease the chances of the primiparous cow to conceive at first service. Genetic correlations between BCS and calving traits were generally the strongest at calving and decreased with increasing days in milk. The correlation between BCS at calving and maternal calving ease was 0.21 for Holstein and 0.31 for Ayrshire and emphasized the relationship between fat cows around calving and dystocia. Genetic correlations between calving traits and BCS during the subsequent lactation were moderate and favorable, indicating that primiparous cows with a genetically high BCS over the lactation would have a greater chance of producing a calf that survived (maternal calf survival) and would transmit the genes that allowed the calf to be born more easily (maternal calving ease) and to survive (direct calving ease). [less ▲]

Short communication: Genetic relationship between calving traits and body condition score before and after calving in Canadian Ayrshire second-parity cows.

in Journal of Dairy Science (2010), 93(9), 4398-403

The objective of this study was to investigate the genetic relationship between body condition score (BCS) and calving traits (including calving ease and calf survival) for Ayrshire second-parity cows in ... [more ▼]

The objective of this study was to investigate the genetic relationship between body condition score (BCS) and calving traits (including calving ease and calf survival) for Ayrshire second-parity cows in Canada. The use of random regression models allowed assessment of the change of genetic correlation from 100 d before calving to 335 d after calving. Therefore, the influence of BCS in the dry period on subsequent calving could be studied. Body condition scores were collected by field staff several times over the lactation in 101 herds from Quebec and calving records were extracted from the official database used for Canadian genetic evaluation of calving ease. Daily heritability of BCS increased from 0.07 on d 100 before calving to 0.25 at 335 d in milk. Genetic correlations between BCS at different stages ranged between 0.59 and 0.99 and indicated that genetic components for BCS did not change much over lactation. With the exception of the genetic correlation between BCS and direct calving ease, which was low and negative, genetic correlations between BCS and calving traits were positive and moderate to high. Correlations were the highest before calving and decreased toward the end of the ensuing lactation. The correlation between BCS 10 d before calving and maternal calving ease was 0.32 and emphasized the relationship between fat cows before calving with dystocia. Standards errors of the genetic correlations estimates were low. Genetic correlations between BCS and calf survival were moderate to high and favorable. This indicates that cows with a genetically high BCS across lactation would have a greater chance of producing a calf that survived (maternal calf survival) and that they would transmit genes that allow the calf to survive (direct calf survival). [less ▲]

Genetic variability of milk components based on mid-infrared spectral data.

in Journal of Dairy Science (2010), 93(4), 1722-1728

The aim of this study was to estimate the genetic parameters of the mid-infrared (MIR) milk spectrum represented by 1,060 data points per sample. The dimensionality of traits was reduced by principal ... [more ▼]

The aim of this study was to estimate the genetic parameters of the mid-infrared (MIR) milk spectrum represented by 1,060 data points per sample. The dimensionality of traits was reduced by principal components analysis. Therefore, 46 principal components describing 99.03% of the phenotypic variability were used to create 46 new traits. Variance components were estimated using canonical transformation. Heritability ranged from 0 to 0.35. Twenty-five out of 46 studied traits showed a permanent environment variance greater than genetic variance. Eight traits showed heritability greater than 0.10. Variances of original spectral traits were obtained by back transformation. Heritabilities for each spectral data points ranged from 0.003 to 0.42. In particular, 3 MIR regions showing moderate to high heritability estimates were of potential genetic interest. Heritabilities for specific wave numbers, linked with common milk traits (e.g., lipids, lactose), were similar to those estimated for these traits. This research confirms the genetic variability of the MIR milk spectrum and, therefore, the genetic variation of milk components. The objective of this study was to better understand the genetics of milk composition and, maybe in the future, to select animals to improve milk quality. [less ▲]

Using body condition score to select for better reproductive performance

Article for general public (2010)

Convention de collaboration technique et scientifique dans le cadre des évaluations génétiques (indexations) porcines de l’AWEP

Report (2010)

Development of a new crossbred based evaluation for carcass quality of Piétrain boars in the Walloon Region of Belgium

Poster (2010)

The aim of this study was to develop a genetic evaluation model to estimate the genetic merit of Piétrain boars for some carcass quality traits. These boars are now evaluated on performances recorded on ... [more ▼]

The aim of this study was to develop a genetic evaluation model to estimate the genetic merit of Piétrain boars for some carcass quality traits. These boars are now evaluated on performances recorded on their crossbred progeny fattened in a central test station. Data provided by the on-farm performance recording system were utilized in this study. Traits analysed were backfat thickness (BF) and lean meat percentage (%meat). The data file contains 60 546 records measured on pigs between 150 and 300 days of age. Model developed was a multitrait animal model. Fixed effects were sex, contemporary groups and heterosis, modeled as regression on heterozygosity. Random effects were additive genetic and permanent environment, modeled by random regressions using linear splines, and residual. Variance components were estimated by restricted maximum likelihood (REML) method on random samples of the total dataset and then confirmed by a Gibbs sampling algorithm on the total dataset. Fit of the model was tested by computing residuals from a BLUP (Best Linear Unbiased Prediction) evaluation. BF and %meat have a high heritability that increase with age. These two traits are also highly genetically correlated. Mean residuals are not significantly different from zero for both traits. Given that BF and %meat had high heritability, genetic improvement of carcass quality is possible by selection on these two traits. Like residuals are close to zero for both traits, it seems that model developed explain a great proportion the variance in each traits. [less ▲]

Development of a new genetic evaluation model for carcass quality based on crossbred performances of Piétrain boars in the Walloon Region of Belgium

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

In context of the development of the genetic evaluation system of Piétrain boars for crossbred performances, a genetic evaluation model was developed for the estimation of genetic merit of boars for ... [more ▼]

In context of the development of the genetic evaluation system of Piétrain boars for crossbred performances, a genetic evaluation model was developed for the estimation of genetic merit of boars for backfat thickness (BF) and meat percentage (%meat). The model developed was a random regression model using linear splines on age which knots at 175, 200 and 250 days. Variance components were estimated by restricted maximum likelihood and Gibbs sampling. Estimated heritability from 150 to 300 days increased from 0.56 to 0.75 for BF and from 0.55 to 0.69 for %meat. Genetic correlation between BF and %meat varied between -0.90 and -0.93 from 150 to 300 days. According to the study of residuals, the developed model was considered to fit well the data especially between 175 and 250 days of age. [less ▲]