SOURCES OF SPECIFIC VARIANCE AND HERITABILITY OF FREE JUMP QUALITIES IN 2-YEARS OLD HORSES FROM THE EAST BULGARIAN BREED

Maya Popova, Svetlozar Kastchiev, Iliyana Sabeva

Abstract: The influence of different sources of variability on the phenotypic variance of free jump qualities, the rate of the additive variance and the correlative relationships with traits characterizing movement have been studied. The study was carried out on the basis of data from the complex assessment by its own productivity of 191 East Bulgarian horses at the age of 2 years old, tested during the period of 2006-2016. Performance tests for 2 years old horses have been conducted in two consecutive days with pre-adaptive period for one week. No preliminary selection has been applied for the participants. There was a relatively constant structure of judging committee. Qualities of free jump (without rider) and allures were evaluated with a 10-score system with accuracy to 0.5. Registration of animals and traits was made by Association East Bulgarian Horse. Analyses of variance, estimations of different sources of variability, heritability and correlations were made by mixed model methodology. Family belonging of horses, lineal belonging of dams and sex were statistically proven sources of pheno¬typic variance. The progeny of mares from Ohota, Likuiushta and Longuza families, and those originated from world famous in sport horse lines of Devis Own (through stallions Da Kapo and Don Primero), Ramzes (through Raskalino), Alme Z (through Kuidams Rubin) and Ladykiller (through Limnos) was characterized with very good jumping abilities. Favorable genetic correlations were established between qualities of free jump and: correctness (0.59); overall gaits (0.39); qualities of free gallop (0.35). Phenotypic and genetic correlations between qualities of free jump and evaluation of walk and trot were low. There were moderate values of free jump heritability.

Keywords: 2-years old sport horse; correlation; free jump; heritability; performance test

Date published: 2018-06-01