Dubois, C., Manfredi, E., & Ricard, A. (2008). Optimization of breeding schemes for sport horses. Livestock Science, 118(1-2), 99–112.
Abstract: A selection scheme for jumping sport horses is modelled with four stages of selection for males and one stage for females. The selection objective included three traits: conformation and gaits (CG, weighted 20%), competition jumping (CJ, weighted 60%) and a third trait (TT, weighted 20%) such as sperm quality or orthopaedic status. The first selection stage is based on knowledge of the pedigree with the aim of selecting horses suitable for CG test (at 3Â years old) and CJ test (at 5Â years old). The second stage includes the horse's own performance with respect to CG and CJ with the aim of selecting horses suitable for the TT test. The third stage is the selection of a limited number of males who are allowed to reproduce. The fourth stage (at 12Â years old) takes into account the results of the horse's progeny. Females are selected in one step, whatever the number of performances measured at 5Â years old. The annual genetic response was 9.4% genetic standard deviation of the objective, 2.6% for CG, 9.0% for CJ and 1.5% for TT. Results showed that selection by progeny testing did not contribute much to genetic response (12% of progeny issued from proven sires), the female pathway represented 26% of genetic response, TT was difficult to improve when the genetic correlation was unfavourable (-Â 0.6% genetic standard deviation for -Â 0.20 genetic correlation), and should consequently be directed towards the use of molecular markers. When compared with a selection scheme involving a station test, genetic response was the same if the breeding values used for selection before entering the station test took into account the results of the relatives for CJ and CG. This revealed the importance of an extensive performance test (like for competition performance) when designing breeding schemes for sport horses.
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Posta, J., Mezei, A., & Mihók, S. (2012). Genetic evaluation of competition years, as a kind of measurement of durability in Hungarian show-jumping horses. In K. Krueger (Ed.), Proceedings of the 2. International Equine Science Meeting (Vol. in press). Wald: Xenophon Publishing.
Abstract: The aim of the study was to investigate the possibilities to use “number of years in competition” as a measure of durability in the genetic evaluation of Hungarian show-jumping horses. Competition results recorder between 1996 and 2009 in show-jumping competitions were used to estimate genetic parameters for number of years in competition. The results were collected by the Show-jumping Group of the Hungarian Horse Breeder’s Society. For estimation of genetic parameters for number of years in competition different linear mixed models were tested. In the first model, sex and birth year were taken into account as fixed effects. In the second model, an adjustment was made for age at first result in competition. The model fit was compared based on their determination coefficient. Variance components were estimated with VCE-6 software package. The determination coefficients of the models were 0.09 and 0.20, while the estimated heritability for number of years in competition was 0.27 and 0.23, respectively.
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