Evaluation of Hungarian Sporthorse mare performance tests

INTRODUCTION The BLUP method was used first by Árnason (1980) in horse breeding for Icelandic Toelter horses. Utilization of this method spread very quickly. Tav ernier (1988) wrote about the application of BLUP procedures in France and there was some information from the Swedish adaptation in Philipsson’s (2005) study. A German breeding estimation method developed by Me inardus (1988) is based on show jumping and dressag  results. The results of further German works and de velopments for estimation methods can be found in L ührsBehnke et al. (2005) and Velsen-Zerweck – Bruns (19 98) studies. Importance of performance tests and po ssible utilization of its results are also reported by Lew czuk et al. (2004ab). For the improvement of breeding value estimation in Hungary, the application and correction (if it is necessary) of widely used methods is needed. Prelim inary analysis of Hungarian Sporthorse performance data were done by Posta et al. (2007). Our analysis was done in correspondence with The Association of Hung arian Horse Breeders and Horse Organization and The Assoc iation of Hungarian Sporthorse Breeders (MSLT). The  aims of the study were breeding value estimation an d construction of breeding value indexes for the ev aluated traits in the performance test of Hungarian Sportho rse mares


INTRODUCTION
The BLUP method was used first by Árnason (1980) in horse breeding for Icelandic Toelter horses. Utilization of this method spread very quickly. Tavernier (1988) wrote about the application of BLUP procedures in France and there was some information from the Swedish adaptation in Philipsson's (2005) study. A German breeding estimation method developed by Meinardus (1988) is based on show jumping and dressage results. The results of further German works and developments for estimation methods can be found in Lührs-Behnke et al. (2005) and Velsen-Zerweck -Bruns (1998) studies. Importance of performance tests and possible utilization of its results are also reported by Lewczuk et al. (2004ab).
For the improvement of breeding value estimation in Hungary, the application and correction (if it is necessary) of widely used methods is needed. Preliminary analysis of Hungarian Sporthorse performance data were done by Posta et al. (2007). Our analysis was done in correspondence with The Association of Hungarian Horse Breeders and Horse Organization and The Association of Hungarian Sporthorse Breeders (MSLT). The aims of the study were breeding value estimation and construction of breeding value indexes for the evaluated traits in the performance test of Hungarian Sporthorse mares

MATERIALS AND METHODS
The data set used for the analysis was supplied by MSLT. Test records of three-year-old and four-year-old mares from 1993 to 2009 were analyzed. There were 593 records from 3-year-old and 299 records from 4-yearold mares, respectively. One hundred-nine mares were tested at both ages.
The mare performance test consists of conformation judgement, free jumping and movement analysis. Traits judged at mare performance test: Conformation traits: type, head, neck, saddle region, frame, forelimbs, hind limbs, regulatory of movement, impulsion and elasticity of movement, overall impression.
Free jumping: jumping style, jumping ability-sense of distance; jumping skill. Movement analysis: walk, trot, canter, overall impression. (MSLT, 2006) The scores of free jumping and movement analysis traits were scored between 0 and 10. Conformation traits were judged by weighting the riding horse qualities since 2000. Weighted traits (neck, forelimbs, hind limbs and impulsion and elasticity of movement) were scored in a 0-12 scale. Type (0-6), head and frame (0-8) were judged in a smaller interval. Other conformational traits were scored between 0 and 10. All traits were judged by a committee and the horse gets the mean of the scores of the committee members. The final score of mare test contains the mean of the conformation score, the mean of free jumping performance scores and the mean of movement analysis scores multiplied by 1, 2, and 2, respectively (MSLT, 2006).
Including the breeder in the model made no significant improvement, so its inclusion was not necessary.
Breeding values were presented with the mean 100 and standard deviation of 20 Koenen [2005] using the formula: where EBV p is the estimated BV on the publication scale; EBV u is the estimated BV on the original scale; meanu is the mean estimated BV on the original scale of the population and σu is the standard deviation of estimated BV on the original scale of the population.
Reliability was computed based on the estimated error variance for every trait in the case of each animal using the following formula: where r is the correlation between the estimated and true genetic value; PEV is the predicted error variance of the breeding value and σ a 2 is the genetic variance of the measured trait.

RESULTS AND DISCUSSION
Means and standard deviations for the traits scored in the performance test are given in Table 1. Differences in the number of horses between different trait groups are due to the fact that some horses did not complete all of the tests. Heritabilities of individual traits were moderate to high as shown in Table 2. Estimated heritabilities were in the range of 0.32 (neck) and 0.50 (saddle region), 0.39 (jumping style) and 0.49 (both jumping skill and jumping ability) and 0.20 (walk) and 0.48 (canter) for conformational traits, free jumping traits and movement analysis traits, respectively.
Estimated heritabilities for some conformational traits were higher than that presented by Hartmann (1999) (traits were: type, head, neck, forelimbs, hind limbs) or Nissen (1997) (traits were: type, forelimbs, hind limbs). For movement analysis traits comparing estimated heritabilities (Table 2), there were similar results for walk (h 2 =0.22), but greater values for trot and canter than estimated by Huizinga et al. (1990). The heritabilities in this study were similar to the heritability estimates for walk and trot given by Luehrs-Behnke et al. (2002).
As a result of discussions with sport horse breeders, there was a demand to construct breeding value indexes to sum the estimated breeding values (EBV) of the evaluated traits. A Conformation Index was developed to summarize the EBVs of the ten conformational traits (Figure 1.). As the traits are thought not be equally important for a riding horse, some trait were weighted in the index. The weights of each trait were the same as the maximum point of the trait.  The four movement analysis traits were scored on the same scale, so they were inserted into the Movement Index with equal weights (Figure 2.).  Free jumping Index was constructed similarly; the three free jumping performance traits were used with equal weights in the index (Figure 3.). Furthermore, an overall index was also developed based on the three indexes mentioned above. The members of the index were weighted based on the regulation of the Breeder Association (Figure 4.).    The reliability of the estimated breeding values is also shown for each trait. The stallion "Goliath" seems to be an overall positive stallion, because its breeding value indexes are more than one standard deviation above the overall mean (100) of the stock. It is important to emphasize that notable progress could be expected in a trait only with the preference of stallions (and offspring of these stallions) whose breeding values approximate to the three standard deviation, but at least one standard deviation greater than the population mean. The reliability values were above 0.7 for almost each trait. 'Jumping ability' was scored only for the last four years this might cause the lower reliability value. To improve the reliability of the estimated breeding values, the evaluation of more offspring would be necessary in the performance tests.