Phenotypic and genetic parameters of the complex assessment of BV in two-year-old tested horses from the east Bulgarian breed
Iliana Sabeva
Abstract: A study has been conducted on the parameters characterizing the value of the phenotypic and genetic variance for the complex assessment of BV in tested two-year-old horses from the East Bulgarian breed. No preliminary selection has been applied on the participants. The judge panel has been relatively constant. The 10 score system was applied with accuracy up to 0.5%. The statistical analysis and evaluation of the phenotypic and genetic variance have been performed on the mixed model methodology.
The evaluation of groups of traits forming the complex BV had a relatively symmetrical geometrical distribution. A large part of animals have been rated lower than the average, in terms of gaits (total), walk, trot and free jump, as a higher peakedness of distribution, established for the correctness and walk. The magnitude of the differences between the planned and realized selection weight, established for the type, exterior and the walk, can be an indicator of necessity for eventual change in the criteria forming the final estimation of group of traits, or for change in the planned selection weight. Sources of mathematically proven specific variance in terms of the complex assessment have been the lines, birth months and gender. Well expressed superiority above the average had the representatives of the Zenger, Tihany and Da Kapo lines. Horses, originating from the formed abroad lines Ramzes, Cor de la Btyere, Cottage Son and Ladykiller, have received a high positive estimation. The complex assessment has a moderate heritability and high in value phenotypic and genetic correlation relations with the other groups of traits, with the exception of free jump. Phenotypic and genetic correlation between type and exterior, gaits and complex assessment have been higher in value. The established correlation between type and free jump, between gaits and body measurements were low, and between type and body measurements, between free jump and exterior, and between free jump and movements – moderate. From a breeding point of view, existing are favorable opportunities for applying an indirect selection, in terms of type and body measurements.
The evaluation of groups of traits forming the complex BV had a relatively symmetrical geometrical distribution. A large part of animals have been rated lower than the average, in terms of gaits (total), walk, trot and free jump, as a higher peakedness of distribution, established for the correctness and walk. The magnitude of the differences between the planned and realized selection weight, established for the type, exterior and the walk, can be an indicator of necessity for eventual change in the criteria forming the final estimation of group of traits, or for change in the planned selection weight. Sources of mathematically proven specific variance in terms of the complex assessment have been the lines, birth months and gender. Well expressed superiority above the average had the representatives of the Zenger, Tihany and Da Kapo lines. Horses, originating from the formed abroad lines Ramzes, Cor de la Btyere, Cottage Son and Ladykiller, have received a high positive estimation. The complex assessment has a moderate heritability and high in value phenotypic and genetic correlation relations with the other groups of traits, with the exception of free jump. Phenotypic and genetic correlation between type and exterior, gaits and complex assessment have been higher in value. The established correlation between type and free jump, between gaits and body measurements were low, and between type and body measurements, between free jump and exterior, and between free jump and movements – moderate. From a breeding point of view, existing are favorable opportunities for applying an indirect selection, in terms of type and body measurements.
Keywords: breeding value; estimation; genetic parameters; tested horses; two-year old
Date published: 2019-12-20
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