| 1. |
- Berglund, Paulina, et al.
(författare)
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Should performance at different race lengths be treated as genetically distinct traits in Coldblooded trotters?
- 2024
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Ingår i: Journal of Animal Breeding and Genetics. - 0931-2668 .- 1439-0388. ; 141, s. 220-234
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Tidskriftsartikel (refereegranskat)abstract
- Speed, in the form of racing time per kilometre (km), is a performance trait of the Swedish-Norwegian Coldblooded trotter included in the joint Swedish-Norwegian genetic evaluation. A few popular stallions have dominated Coldblooded trotter breeding, which has led to an increasing average relationship between individuals in the population. This study investigated the scope for broadening the breeding goal by selecting for racing time per km over different race lengths (short: 1640 m, medium: 2140 m and long: 2640 m), as this could encourage the use of breeding sires that are less related to the population. Performance data on three- to 12-year-old Coldblooded trotters in all Swedish races run 1995-2021 were obtained from the Swedish Trotting Association. These data consisted of 46,356 observations for 8375 horses in short-distance races, 430,512 observations for 11,193 horses in medium-distance races and 11,006 observations for 3341 horses in long-distance races. Variance components and genetic correlations were calculated using a trivariate animal model with Gibbs sampling from the BLUPF90 suite of programs. Breeding values for the three traits were then estimated using univariate animal models with the same fixed and random effects as in the trivariate model. Heritability estimates of 0.27-0.28 and genetic correlations between racing time per km at the different distances of 0.97-0.99 were obtained. Despite the strong genetic correlation between the traits, there was some re-ranking among the top 10 and top 30 stallions based on distance-specific breeding values. Estimated rank correlation between breeding values for racing time per km in short- and medium-distance races was 0.86, while between short- and long-distance races and between medium- and long-distance races it was 0.61. Mean relationship within the top 10 and top 30 stallions based on breeding values for racing time per km at each distance was 0.31-0.33 and 0.23-0.24 while mean relationship to the rest of the population ranged from 0.17 to 0.18 for all groups, although the 10 and 30 top-ranking stallions differed somewhat in the traits. Estimated average increase in inbreeding was 0.1% per year of birth and 1.2% per generation. The strong genetic correlation between racing time per km at different distances did not support their use as genetically distinct traits. Re-ranking of stallions for racing time per km at different race lengths could favour the use of a larger number of stallions in breeding, but according to our results it would not promote the use of stallions that are less related to the total population. Other traits like longevity or health traits, for example, career length and orthopaedic status, may be more relevant in broadening the breeding goal and preventing a few sires dominating future breeding, and this would be interesting to study further.
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| 2. |
- Harish, Ajith, et al.
(författare)
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Genetic diversity and recent ancestry based on whole-genome sequencing of endangered Swedish cattle breeds
- 2024
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Ingår i: BMC Genomics. - 1471-2164. ; 25
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Tidskriftsartikel (refereegranskat)abstract
- Several indigenous cattle breeds in Sweden are endangered. Conservation of their genetic diversity and genomic characterization is a priority.Whole-genome sequences (WGS) with a mean coverage of 25X, ranging from 14 to 41X were obtained for 30 individuals of the breeds Fjallko, Fjallnara, Bohuskulla, Rodkulla, Ringamala, and Vaneko. WGS-based genotyping revealed 22,548,028 variants in total, comprising 18,876,115 single nucleotide polymorphisms (SNPs) and 3,671,913 indels. Out of these, 1,154,779 SNPs and 304,467 indels were novel. Population stratification based on roughly 19 million SNPs showed two major groups of the breeds that correspond to northern and southern breeds. Overall, a higher genetic diversity was observed in the southern breeds compared to the northern breeds. While the population stratification was consistent with previous genome-wide SNP array-based analyses, the genealogy of the individuals inferred from WGS based estimates turned out to be more complex than expected from previous SNP-array based estimates. Polymorphisms and their predicted phenotypic consequences were associated with differences in the coat color phenotypes between the northern and southern breeds. Notably, these high-consequence polymorphisms were not represented in SNP arrays, which are used routinely for genotyping of cattle breeds.This study is the first WGS-based population genetic analysis of Swedish native cattle breeds. The genetic diversity of native breeds was found to be high. High-consequence polymorphisms were linked with desirable phenotypes using whole-genome genotyping, which highlights the pressing need for intensifying WGS-based characterization of the native breeds.
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| 3. |
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| 4. |
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| 5. |
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| 6. |
- Sigurðardóttir, Heiðrún, et al.
(författare)
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Nya passgener upptäckta
- 2024
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Ingår i: Icehorse. - 2003-4571. ; , s. 46-47
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Tidskriftsartikel (populärvet., debatt m.m.)
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| 7. |
- Bengtsson, Christian, et al.
(författare)
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Mating allocations in Holstein combining genomic information and linear programming optimization at the herd level
- 2023
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Ingår i: Journal of Dairy Science. - 0022-0302 .- 1525-3198. ; 106, s. 3359-3375
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Tidskriftsartikel (refereegranskat)abstract
- In this study, we explored mating allocation in Hol-stein using genomic information for 24,333 Holstein fe-males born in Denmark, Finland, and Sweden. We used 2 data sets of bulls: the top 50 genotyped bulls and the top 25 polled genotyped bulls on the Nordic total merit scale. We used linear programming to optimize economic scores within each herd, considering genetic level, genetic relationship, semen cost, the economic impact of genetic defects, polledness, and 0-casein. We found that it was possible to reduce genetic relation-ships and eliminate expression of genetic defects with minimal effect on the genetic level in total merit index. Compared with maximizing only Nordic total merit in-dex, the relative frequency of polled offspring increased from 13.5 to 22.5%, and that of offspring homozygous for 0-casein (A2A2) from 66.7 to 75.0% in one genera-tion, without any substantial negative impact on other comparison criteria. Using only semen from polled bulls, which might become necessary if dehorning is banned, considerably reduced the genetic level. We also found that animals carrying the polled allele were less likely to be homozygous for 0-casein (A2A2) and more likely to be carriers of the genetic defect HH1. Hence, adding economic value to a monogenic trait in the economic score used for mating allocation sometimes negatively affected another monogenetic trait. We rec-ommend that the comparison criteria used in this study be monitored in a modern genomic mating program.
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| 8. |
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| 9. |
- Blom, Ylva, et al.
(författare)
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Start status in Swedish Warmblood horses
- 2023
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Ingår i: Annual meeting of the European Association for Animal Production. - 1382-6077. ; 29, s. 979-979
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Konferensbidrag (refereegranskat)
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| 10. |
- Bonow, Sandra, et al.
(författare)
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Consequences of specialized breeding in the Swedish Warmblood horse population
- 2023
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Ingår i: Journal of Animal Breeding and Genetics. - : Wiley. - 0931-2668 .- 1439-0388. ; 140, s. 79-91
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Tidskriftsartikel (refereegranskat)abstract
- In many European warmblood studbooks, clear specialization toward either jumping or dressage horses is evident. The Swedish Warmblood (SWB) is also undergoing such specialization, creating a possible need for separate breeding programs and a discipline-specific Young Horse Test (YHT). This study investigated how far specialization of the SWB breed has proceeded and the potential consequences. Individuals in a population of 122,054 SWB horses born between 1980 and 2020 were categorized according to pedigree as jumping (J), dressage (D), allround (AR), or thoroughbred (Th). Data on 8,713 J horses and 6,477 D horses assessed for eight traits in YHT 1999-2020 were used to estimate genetic parameters within and between J and D horses and between different periods. Future scenarios in which young horses are assessed for either jumping or dressage traits at YHT were also analyzed. More than 80% of horses born in 1980-1985 were found to be AR horses, while 92% of horses born in 2016-2020 belonged to a specialized category. The average relationship within J or D category was found to increase during the past decade, whereas the relationship between these categories decreased. Heritability estimates for gait traits were 0.42-0.56 for D horses and 0.25-0.38 for J horses. For jumping traits, heritability estimates were 0.17-0.26 for J horses and 0.10-0.18 for D horses. Genetic correlations between corresponding traits assessed in J and D horses were within the range 0.48-0.81, with a tendency to be lower in the late study period. In the future scenarios, heritability and genetic variance both decreased for traits that were not assessed in all horses, indicating that estimation of breeding value and genetic progress for these traits could be affected by a specialized YHT. However, ranking of sires based on estimated breeding values (EBVs) and accuracy of EBVs was only slightly altered for discipline-specific traits. With continued specialization in SWB, specialization of the YHT should thus be considered.
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