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- Braam, Åsa, et al.
(författare)
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Förord: BLUP-index 2011
- 2012
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Ingår i: Hingstar verksamma inom svensk halvblodsavel. ; , s. 253-254
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Tidskriftsartikel (populärvet., debatt m.m.)
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- Viklund, Åsa, et al.
(författare)
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Genetic variation in competition traits at different ages and time periods and correlations with traits at field tests of 4-year-old Swedish Warmblood horses
- 2010
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Ingår i: Animal. - 1751-7311 .- 1751-732X. ; 4, s. 682-691
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Tidskriftsartikel (refereegranskat)abstract
- For many years, the breeding value estimation for Swedish riding horses has been based on results from Riding Horse Quality Tests (RHQTs) of 4-year-olds only. Traits tested are conformation, gaits and jumping ability. An integrated index including competition results is under development to both get as reliable proofs as possible and increases the credibility of the indexes among breeders, trainers and riders. The objectives of this study were to investigate the suitability of competition data for use in genetic evaluations of horses and to examine how well young horse performance agrees with performance later in life. Competition results in dressage and show jumping for almost 40 000 horses from the beginning of the 1960s until 2006 were available. For RHQT data of 14 000 horses judged between 1988 and 2007 were used. Genetic parameters were estimated for accumulated competition results defined for different age groups (4 to 6 years of age, 4 to 9 years of age and lifetime), and for different birth year groups. Genetic correlations were estimated between results at RHQT and competitions with a multi-trait animal model. Heritabilities were higher for show jumping than dressage and increased with increasing age of the horse and amount of information. For dressage, heritabilities increased from 0.11 for the youngest group to 0.16 for lifetime results. For show jumping corresponding values increased from 0.24 to 0.28. Genetic correlations between competition results for the different age groups were highly positive (0.84 to 1.00), as were those between jumping traits at RHQT and competition results in show jumping (0.87 to 0.89). For dressage-related traits as 4-year-old and dressage competition results the estimated genetic correlations were between 0.47 and 0.77. We suggest that lifetime results from competitions should be integrated into the genetic evaluation system. However, genetic parameters showed that traits had changed during the over 35-year period covered due to the development of the sport, which needs to be considered in future genetic evaluations.
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- Braam, Åsa
(författare)
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Breeding for durable riding horses using competition statistics
- 2011
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The breeding objectives for Swedish Warmblood horses are aiming for producing horses that have a good conformation and are internationally competitive in dressage and show jumping. It also states that the horses should be durable. The aim of this thesis was to investigate whether it is possible to use existing competition statistics for genetic evaluation of durability and, if so, how this should be done. Number of years in competition (NYC) was used as a measure of durability. Genetic analyses were performed using linear animal models where heritabilities, genetic correlations, and breeding values (EBV) were estimated. It was concluded that birth year and age at first placing should be included as fixed effects in the model. Age at first placing is, to a great extent, reflecting the talent of the horse and since information about durability is desired, the suggestion is to adjust for the age effect in the analyses of NYC. Three different datasets were tested when heritabilities and EBVs were estimated. The datasets varied based on sex and birth year of the included horses. Heritabilities for NYC were in the same range for all three datasets (total 0.06-0.07; show jumping 0.08-0.12; dressage 0.07-0.08; eventing 0.04-0.08) and there were high correlations between EBVs within the same discipline for the different datasets. The genetic correlations between total NYC and performance traits from competition and Riding Horse Quality Test (RHQT) were higher for jumping traits (0.65-0.69) than for dressage (0.27-0.40) indicating that there are connections between level of performance and NYC. The conclusions of the results were that it is recommended to estimate EBVs for NYC for stallions with a linear animal model and that they should be published for each discipline separately. Besides the genetic analyses, the study showed that horses with successful results from more than one discipline at an early age had significantly more years in competition compared to the other horses. This indicates that an all-round training of young horses has a positive effect on the durability of the horse.
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- Braam, Åsa, et al.
(författare)
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Genetic variation in durability of Swedish Warmblood horses using competition results
- 2011
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Ingår i: Livestock Science. - : Elsevier BV. - 1871-1413 .- 1878-0490. ; 142, s. 181-187
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Tidskriftsartikel (refereegranskat)abstract
- The aim of the study was to investigate the possibilities of using number of years in competition as a measure of durability in the genetic evaluation of Swedish Warmblood horses. Competition results recorded between 1971 and 2008 in the disciplines dressage, show jumping and eventing were used to estimate genetic parameters for number of years in competition. Only male horses not used in breeding born between 1967 and 1991 were included in the study (17,962 horses). The study showed that horses with placings in more than one discipline at an early age had the longest competition career. This result suggests that these horses are talented for sports and possibly also that there is a positive effect of all-round training of young horses on their durability. For estimation of genetic parameters for number of years in competition different linear mixed animal models were compared. Depending on the model and transformation the heritability for total number of years in competition varied between 0.07 and 0.17. The lower values were obtained when adjustments in the model were made for age at first placing in competition. Higher heritabilities were obtained for competition years in show jumping and lower for eventing. Performance traits scored at young horse tests and as points in competition (lifetime and for young horses) showed positive genetic correlations with total number of years in competition. These results indicate that years in competition represent both the durability of the horses and their talents for performance. It is suggested that number of years in competition may be used for genetic evaluation of durability.
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