A common reference population from four European Holstein populations increases reliability of genomic predictions.

in Genetics, Selection, Evolution [=GSE] (2011), 43(1), 43

ABSTRACT: BACKGROUND: Size of the reference population and reliability of phenotypes are crucial factors influencing the reliability of genomic predictions. It is therefore useful to combine closely ... [more ▼]

ABSTRACT: BACKGROUND: Size of the reference population and reliability of phenotypes are crucial factors influencing the reliability of genomic predictions. It is therefore useful to combine closely related populations. Increased accuracies of genomic predictions depend on the number of individuals added to the reference population, the reliability of their phenotypes, and the relatedness of the populations that are combined. METHODS: This paper assesses the increase in reliability achieved when combining four Holstein reference populations of 4000 bulls each, from European breeding organizations, i.e. UNCEIA (France), VikingGenetics (Denmark, Sweden, Finland), DHV-VIT (Germany) and CRV (The Netherlands, Flanders). Each partner validated its own bulls using their national reference data and the combined data, respectively. RESULTS: Combining the data significantly increased the reliability of genomic predictions for bulls in all four populations. Reliabilities increased by 10%, compared to reliabilities obtained with national reference populations alone, when they were averaged over countries and the traits evaluated. For different traits and countries, the increase in reliability ranged from 2% to 19%. CONCLUSIONS: Genomic selection programs benefit greatly from combining data from several closely related populations into a single large reference population. [less ▲]

GENOMIC SELECTION IN FRENCH DAIRY CATTLE

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

Estimation of genetic parameters and genome scan for 15 semen characteristics traits of Holstein bulls.

in Journal of Animal Breeding & Genetics (2009), 126(4), 269-77

A QTL detection experiment was performed in French dairy cattle to search for QTL related to male fertility. Ten families, involving a total of 515 bulls, were phenotyped for ejaculated volume and sperm ... [more ▼]

A QTL detection experiment was performed in French dairy cattle to search for QTL related to male fertility. Ten families, involving a total of 515 bulls, were phenotyped for ejaculated volume and sperm concentration, number of spermatozoa, motility, velocity, percentage of motile spermatozoa after thawing and abnormal spermatozoa. A set of 148 microsatellite markers were used to realize a genome scan. First, genetic parameters were estimated for all traits. Semen production traits were found to have moderate heritabilities (from 0.15 to 0.30) while some of the semen quality traits such as motility had high heritabilities (close to 0.60). Genetic correlations among traits showed negative relationships between volume and concentration and between volume and most quality traits such as motility or abnormal sperm while correlations between concentration and these traits were rather favourable. Percentages of abnormal sperm were negatively related to quality traits, especially with motility and velocity of spermatozoa. Three QTL related to abnormal sperm frequencies were significant at p < 0.01. In total, 11 QTL (p < 0.05) were detected. However, the number of QTL detected was within the range of expected false positives. Because of the lack of power to find QTL in this design further analyses are required to confirm these QTL. [less ▲]

A Generalized Caprine-like Hypoplasia Syndrome is localized within a 6-cM interval on bovine chromosome 13 in the Montbeliarde breed.

in Animal Genetics (2008), 39(2), 112-20

Caprine-like Generalized Hypoplasia Syndrome (or SHGC) is a new hereditary disorder described in the Montbeliarde breed. We report here the characterization of this new disease, based on the visual ... [more ▼]

Caprine-like Generalized Hypoplasia Syndrome (or SHGC) is a new hereditary disorder described in the Montbeliarde breed. We report here the characterization of this new disease, based on the visual examination of animals affected by SHGC, and on physiological and biochemical studies undertaken on samples of both SHGC and normal animals. Biological samples for more than 150 affected calves and their parents have been collected over the past 4 years within the framework of the Bovine Genetic Disease Observatory. First, pedigree analyses showed that the mode of inheritance is most probably autosomal recessive. Then, a genome scan with 113 animals and 140 microsatellite markers revealed a single locus within a 35-cM region on bovine chromosome 13. Genotypes of 261 animals for 18 new microsatellite markers from the region confirmed the localization of the disorder to a 6-cM interval. Finally, based on the analysis of haplotypes in 463 Montbeliarde sires, we estimated the frequency of the SHGC mutated allele in the population and could propose a strategy for the systematic eradication of this disorder in the near future. [less ▲]

Refinement of two female fertility QTL using alternative phenotypes in French Holstein dairy cattle.

in Animal Genetics (2007), 38(1), 72-4

Two quantitative trait loci (QTL) affecting female fertility were mapped in French dairy cattle. Phenotypes were non-return rates at 28, 56, 90 and 282 days after insemination. On chromosome 3, a QTL was ... [more ▼]

Two quantitative trait loci (QTL) affecting female fertility were mapped in French dairy cattle. Phenotypes were non-return rates at 28, 56, 90 and 282 days after insemination. On chromosome 3, a QTL was significant at 1% for non-return rate at 90 days, suggesting that it affects early fertility events. An analysis of SLC35A3, which causes complex vertebral malformation, excluded this gene from the QTL interval. On chromosome 7, a QTL was almost significant (P = 0.05) for non-return rate at 282 days. This QTL was associated with abortion and stillbirth problems. Use of appropriate phenotypes appeared important for fine-mapping QTL associated with fertility. [less ▲]

Use of SNP for marker assisted selection in French dairy cattle

in Book of abstracts from the 58th Annual Meeting of the European Association for Animal Production (2007)

Bilan du programme de Sélection Assistée par Marqueurs dans les trois principales races bovines laitières françaises et perspectives d’évolution

in Renc. Rech. Ruminants, 2007, 14 (2007)

Implementation of marker-assisted selection: practical lessons from dairy cattle

in Proceedings of the 8th World Congress on Genetics Applied to Livestock Production (2006)

Estimation of genetic parameters for quantitative trait loci for dairy traits in the French Holstein population.

in Journal of Dairy Science (2006), 89(10), 4070-6

A marker-assisted selection program (MAS) has been implemented in dairy cattle in France. The efficiency of such a selection program depends on the use of correct genetic parameters for the marked ... [more ▼]

A marker-assisted selection program (MAS) has been implemented in dairy cattle in France. The efficiency of such a selection program depends on the use of correct genetic parameters for the marked quantitative trait loci (QTL). Therefore, the objective of this study was to estimate the proportion of genetic variance explained by 4 QTL described in previous studies (these QTL are segregating on chromosomes 6, 14, 20, and 26). Genotypes for 11 markers were available for 3,974 bulls grouped within 54 sire families of the French Holstein population undergoing MAS. The parameters were estimated for 4 QTL and 5 dairy traits: milk, fat and protein yields, and fat and protein percentages. The proportion of genetic variance explained by the QTL ranged from as low as 0.03 to 0.36%. Both lack of marker informativity and poor monitoring of QTL transmission might limit the accuracy of estimation. The QTL explained a larger proportion of genetic variance for milk composition traits. The QTL on chromosome 14 and chromosomes 6 and 20 have their largest influence on fat and protein percentages, respectively. The overall proportions of genetic variance explained by the QTL were 27.0, 30.7, 24.1, 48.2, and 33.6% for milk, fat and protein yields, and fat and protein percentages, respectively. These results clearly indicated that a large part of the genetic variance is explained by a small number of QTL and that their use in MAS might be beneficial for dairy cattle breeding programs. [less ▲]

Estimation de paramètres génétiques et détection de QTL liés à des caractères de fertilité mâle, de production de semence et de qualité de la semence chez le taureau laitier

Poster (2005)