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  • 1
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    Online Resource
    43 Single and Multiple-breed Genomic Predictions for Conformation Traits of Canadian Dairy Goats
    Oxford University Press (OUP) ; 2021
    In:  Journal of Animal Science Vol. 99, No. Supplement_3 ( 2021-10-08), p. 27-28
    Details
    In: Journal of Animal Science, Oxford University Press (OUP), Vol. 99, No. Supplement_3 ( 2021-10-08), p. 27-28
    Abstract: The use of multiple-breed models can increase the accuracy of estimated breeding values (EBV) when few phenotypes are available for a trait. However, pooling breeds is not always beneficial for genomic evaluations due to the low consistency of gametic phase between individual breeds. The objective of this study was to compare the expected gain in accuracy of single-step genomic breeding values (GEBV) for conformation traits of Canadian Alpine and Saanen goats predicted using single and multiple-breed models. The traits considered were body capacity, dairy character, feet and legs, fore udder, general appearance, rear udder, suspensory ligament, and teats, all recorded by trained classifiers, using a 1 to 9 scale. The full datasets included a total of 7,500 phenotypes for each trait (5,158 Alpine and 2,342 Saanen) and 1,707 50K genotypes (833 Alpine, 874 Saanen). Standard errors of prediction (SEP) were obtained for EBV and GEBV predicted using single-trait animal models on full or validation datasets. Breed difference was accounted for as a fixed effect in the multiple-breed models. Average theoretical accuracies were calculated from the SEP. For Saanen, with fewer records, expected accuracies of EBV and GEBV for the validation animals (selection candidates) were consistently higher for the multiple-breed models. Trait specific gains in theoretical accuracy of GEBV relative to EBV for the selection candidates ranged from 30 to 48% for Alpine and 41 to 61% for Saanen. Averaged across all traits, GEBV predicted from the full dataset were 32 to 38% more accurate than EBV for genotyped animals and the largest gains were found for does without conformation records (49 to 55%) and bucks without daughter records (56 to 82%). Overall, the implementation of genomic selection would substantially increase selection accuracy for young breeding candidates and, consequently, the rate of genetic improvement for conformation traits in Canadian dairy goats.
    Type of Medium: Online Resource
    ISSN: 0021-8812 , 1525-3163
    URL: Article
    DOI: 10.1093/jas/skab235.046
    Language: English
    Publisher: Oxford University Press (OUP)
    Publication Date: 2021
    detail.hit.zdb_id: 1490550-4
    SSG: 12
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  • 2
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    A genetic evaluation of growth, ultrasound, and carcass traits at alternative slaughter endpoints in crossbred heavy lambs1
    Oxford University Press (OUP) ; 2019
    In:  Journal of Animal Science Vol. 97, No. 2 ( 2019-02-01), p. 521-535
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    In: Journal of Animal Science, Oxford University Press (OUP), Vol. 97, No. 2 ( 2019-02-01), p. 521-535
    Type of Medium: Online Resource
    ISSN: 0021-8812 , 1525-3163
    URL: Article
    DOI: 10.1093/jas/sky455
    Language: English
    Publisher: Oxford University Press (OUP)
    Publication Date: 2019
    detail.hit.zdb_id: 1490550-4
    SSG: 12
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  • 3
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    Online Resource
    31 Gametic Incompatibility: Improving the Success of Mate Allocation in Dairy Cattle
    Oxford University Press (OUP) ; 2021
    In:  Journal of Animal Science Vol. 99, No. Supplement_3 ( 2021-10-08), p. 16-17
    Details
    In: Journal of Animal Science, Oxford University Press (OUP), Vol. 99, No. Supplement_3 ( 2021-10-08), p. 16-17
    Abstract: In the dairy industry, mate allocation is mainly based on the parents’ breeding values and inbreeding coefficients aiming to achieve the producer’s breeding goal. With artificial insemination, the portfolio of sires to choose from is large and the quality of the semen doses is standardized. However, not all sire-dam matings are equally likely to produce a successful pregnancy. Among other reproduction issues, the success of a mating could vary due to the incompatibility of gametes coming from the sire and the dam and could influence the fertilization’s success, additionally to the reproductive capacity of the parents. Considering the gametic incompatibility of the potential parents could be a novel option to improve mating plans. Under the hypothesis that gametic incompatibility has a significant effect on reproduction and reduces the odds of fertilization and pregnancy, this study aimed to determine the genetic background of gametic incompatibility. Transmission ratio distortion (TRD), which detects deviations from Mendelian inheritance expectations, is commonly used to identify deleterious mutations. We adapted the TRD model by including an interaction effect between the gametes leading to the offspring genotype to detect regions with TRD effects and gametic incompatibility. Our dataset contained 436,651 genotyped (50K SNP) Canadian Holstein cattle from 283,817 parents-offspring trios. A total of 482 regions with TRD containing 671 positional genes were found. The functional analysis detected biological pathways associated with uterus development, embryonic skeletal system development, and nervous system development. Additionally, gene ontology terms from the topology-based pathway enrichment analysis were mostly related to the steroid hormones signalling pathway. Although difficult, genes specific to gametic incompatibility could be differentiated from genes underlying other reproduction processes by refining the genetic regions with TRD. With further investigation, we will provide new information to improve mate allocation for the dairy cattle industry.
    Type of Medium: Online Resource
    ISSN: 0021-8812 , 1525-3163
    URL: Article
    DOI: 10.1093/jas/skab235.026
    Language: English
    Publisher: Oxford University Press (OUP)
    Publication Date: 2021
    detail.hit.zdb_id: 1490550-4
    SSG: 12
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  • 4
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    PSXII-21 The Impact of Genomic Selection on Canadian Holstein Cattle Population Structure
    Oxford University Press (OUP) ; 2022
    In:  Journal of Animal Science Vol. 100, No. Supplement_3 ( 2022-09-22), p. 207-208
    Details
    In: Journal of Animal Science, Oxford University Press (OUP), Vol. 100, No. Supplement_3 ( 2022-09-22), p. 207-208
    Abstract: The Canadian dairy industry implemented genomic selection in 2009 to improve breeding in Holstein cattle and has been applied to several other dairy cattle breeds since then. Genomic selection is an effective breeding tool that can increase the accuracy of prediction and help to select young animals using genotypic information. As well as shortening generation intervals, genomic selection has also increased the genetic gain per generation and the profitability of the industry. However, genomic selection tends to increase inbreeding, reduce the effective population size and cause a loss in genetic variation. These consequences could lead to future challenges like lower selection response. To evaluate the sustainability of current breeding practices, investigation is warranted to observe the effects of genomic selection. Therefore, the objective of this study is to compare the population structure of Canadian Holstein cattle before and after the implementation of genomic selection in 2009. Using pedigree information to identify the number of sires used for breeding at three different time points (2000, 2010 and 2020), the number of daughters per sire, and length of time sires were used were investigated. Results show that the average number of offspring per top sire (top 10%) has decreased by 50%, however the average relatedness of available sires has increased considerably. This information will add to our knowledge of the effects genomic selection has had on the Canadian dairy industry and will inform future recommendations for sustainable breeding strategies that facilitate continual genetic progress.
    Type of Medium: Online Resource
    ISSN: 0021-8812 , 1525-3163
    URL: Article
    DOI: 10.1093/jas/skac247.377
    Language: English
    Publisher: Oxford University Press (OUP)
    Publication Date: 2022
    detail.hit.zdb_id: 1490550-4
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  • 5
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    503 Late-Breaking: Using Random Regression Models to Estimate Genetic Parameters for Milk Production Traits under Different Levels of Heat Stress in Canadian Holstein Cattle
    Oxford University Press (OUP) ; 2021
    In:  Journal of Animal Science Vol. 99, No. Supplement_3 ( 2021-10-08), p. 178-179
    Details
    In: Journal of Animal Science, Oxford University Press (OUP), Vol. 99, No. Supplement_3 ( 2021-10-08), p. 178-179
    Abstract: Genetically selecting animals that are heat tolerant can help to maintain production efficiency of the dairy industry under thermal challenges. During the summer months in Canada, dairy cows could be under thermal stress. For instance, in Ontario, cows are expected to be 105 days under thermal stress. The objective of this study was to estimate genetic parameters for milk production traits under heat stress in Canadian Holstein cows. A total of 604,050 test-day records for milk, fat, and protein yields from 78,516 first-lactation Holstein cows were used in this study. The production data was combined with daily maximum temperature-humidity index (THI; ranging from 30 to 83) calculated based on meteorological records from public weather stations. In total, 58 weather stations were located within a maximum distance of 20 km from each of the 1,284 herds included in this study. Single-trait random regressions on THI, fitting linear splines to describe the random additive genetic and permanent environmental effects, were used in the genetic analyses. Based on preliminary analyses, the knots of the spline functions were set to THI = 70, 57, and 58 for milk, fat, and protein yields, respectively. Therefore, the models assumed a linear effect of heat stress beyond the THI threshold, allowing to estimate the additive genetic effect under thermal comfort and at different levels of heat stress. The genetic correlations estimated between thermal comfort and heat stress were -0.09, -0.33, and -0.21 for milk, fat, and protein yields, respectively. This indicates an antagonistic relationship between level of production and heat tolerance. However, small differences in heritability estimates were observed above the THI thresholds (they ranged from 0.20 to 0.22 for milk, 0.18 to 0.15 for fat, and 0.14 to 0.15 for protein yields). This study demonstrates the possibility of genetically selecting for more heat-tolerant animals in Canada.
    Type of Medium: Online Resource
    ISSN: 0021-8812 , 1525-3163
    URL: Article
    DOI: 10.1093/jas/skab235.326
    Language: English
    Publisher: Oxford University Press (OUP)
    Publication Date: 2021
    detail.hit.zdb_id: 1490550-4
    SSG: 12
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  • 6
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    PSVIII-7 Genetic parameters for health traits in dairy calves
    Oxford University Press (OUP) ; 2021
    In:  Journal of Animal Science Vol. 99, No. Supplement_3 ( 2021-10-08), p. 240-240
    Details
    In: Journal of Animal Science, Oxford University Press (OUP), Vol. 99, No. Supplement_3 ( 2021-10-08), p. 240-240
    Abstract: Recent issues in the dairy industry related to both animal and public health concerns are leading farmers away from the use of drugs, while placing more focus on animal health and welfare. Public demands are also shifting towards ensuring socially acceptable production practices in terms of good animal health and welfare. Such challenges are moving the focus in dairying from solely financial to a broader set of themes that, once addressed, will enhance the sustainability of dairying and provide a long-term competitive advantage for the Canadian industry. Furthermore, from a production standpoint, calf diseases, such as, diarrhea and respiratory disease (RD) have been associated with decreased first lactation production and growth rate, therefore decreasing an animal’s potential lifetime profitability. As part of a larger project aiming to add calf health traits to genetic evaluations in Canadian dairy cattle, this study provides the groundwork through the estimation of genetic parameters of two calf health traits, diarrhea and RD. Data were provided by Lactanet Canada, and included 20,594 calf records for diarrhea from 741 herds, and 48,927 calf records for RD from 1,412 herds, recorded between 2004 and 2021 across Canada. Total herd records ranged between 1 and 3,860 for RD with an average of 37 records per herd, while for diarrhea records ranged between 1 and 3,724 with an average of 28 records per herd. The results of this study will be used to optimally fit both diarrhea resistance and RD resistance into a novel resiliency index for use in national genetic evaluations in Canada.
    Type of Medium: Online Resource
    ISSN: 0021-8812 , 1525-3163
    URL: Article
    DOI: 10.1093/jas/skab235.437
    Language: English
    Publisher: Oxford University Press (OUP)
    Publication Date: 2021
    detail.hit.zdb_id: 1490550-4
    SSG: 12
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  • 7
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    166 Livestock Resiliency: Concepts and Approaches
    Oxford University Press (OUP) ; 2021
    In:  Journal of Animal Science Vol. 99, No. Supplement_3 ( 2021-10-08), p. 89-90
    Details
    In: Journal of Animal Science, Oxford University Press (OUP), Vol. 99, No. Supplement_3 ( 2021-10-08), p. 89-90
    Abstract: Genetic improvement of health, welfare, efficiency, and fertility traits is challenging due to expensive and fuzzy phenotypes, the polygenic nature of traits, antagonistic genetic correlations to production traits and low heritabilities. Nevertheless, many organizations have introduced large-scale genetic evaluations for such traits in routine selection indexes. Medium and high-density arrays can be applied in genomic selection strategies to improve breeding value accuracy, and also in genome-wide association studies (GWAS) to identify causative mutations responsible for economically important traits. Genomic information is particularly helpful when traits have low heritability. The objective here is to provide a framework for including health, welfare, efficiency, and fertility traits taken from large-scale genetic and genomic analyses and identifying areas of potential improvement in terms of trait definition and performance testing. General tendencies between trait groups confirmed that a number of moderate unfavourable correlations (+/-0.20 or higher) exist between economically important trait complexes and health, welfare, and fertility traits. A number of trait complexes were identified in which “closer-to-biology” phenotypes could provide clear improvements to routine genetic and genomic selection programs. Here we outline development of these phenotypes and describe their collection. While conventional variance component estimation methods have underpinned the genomic component of some traits of economic interest, performance testing for health, welfare, efficiency, and fertility traits remains an elusive goal for breeding programs. Although our results are encouraging, there is much to be done in terms of trait definition and obtaining better measures of physiological parameters for wide-scale application in breeding programs. Close collaboration between veterinarians, physiologists, and geneticists is necessary to attain meaningful advancement in such areas. We would like to acknowledge the support and funding from all national and international partners involved in the RDGP project through the Large Scale Applied Research Project program from Genome Canada
    Type of Medium: Online Resource
    ISSN: 0021-8812 , 1525-3163
    URL: Article
    DOI: 10.1093/jas/skab235.159
    Language: English
    Publisher: Oxford University Press (OUP)
    Publication Date: 2021
    detail.hit.zdb_id: 1490550-4
    SSG: 12
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