Pedigree analysis of the racing line Quarter Horse: Genetic diversity and most influential ancestors

Abstract

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Racing Performance of the Quarter Horse: Genetic Parameters, Trends and Correlation for Earnings, Best Time and Time Class

“…There was a decrease in EBVs for all traits with advancing equestrian age (Table 4), suggesting that the animals can be selected early for breeding, i.e., immediately after completing 2 years of equestrian age. This approach makes it possible to reduce the long generational intervals (>10 years) of this population [12]; in fact, the generational interval is one of the limiting factors in the genetic improvement of horse breeding programs.…”

“…The genetic trends have decreased over the last 10 years (2005 to 2014) ( Figure 1 ), a finding that suggests possible stagnation in the genetic evolution of the racing line of the QH breed in Brazil, comparable to that reported for the Thoroughbred breed [ 7 ]. The stagnation and genetic losses observed in the last decade ( Figure 1 ) must be recovered through targeted mating, with an increase in the number of breeding animals with origins different from the ancestors of the QH breed in Brazil, as suggested in the populational study [ 36 ], who observed a genetic bottleneck in the current population of the racing line of the QH breed in Brazil.…”

“…In the present study, considering that 74.9% of the horses participated in their first race at 2 years of equestrian age and following the recommendations by Silva et al [5], earnings at 2 years of equestrian age (E2) was defined as the trait. The prize money won at 2 years of equestrian age was obtained at different times (from 1978 to 2015) and in different Brazilian currencies [12]. The values obtained [5] were then converted to international currency (USD), and the monetary update was obtained for June 2019 [13].…”