Two traits, when considered together, could aid Quarter Horse breeding – study

Genetic improvements in Brazil’s Quarter Horses could be boosted by breeders widening their selection and evaluation criteria, according to researchers.

In fact, the simple addition of racing times to earnings in assessing horses could improve genetic gains for speed-racing Quarter Horses around the world, the authors said.

“The main goal in selecting racehorses for breeding is usually monetary earnings, and animals that earn the highest amounts of money are usually selected for breeding,” researchers Ricardo Faria, António Vicente and Josineudson Silva noted in the journal Animals.

However, these animals are not always the fastest on the racecourse because there are several competitions where the animals were faster, but the prize money for the winners was lower, they said.

This meant that the fastest racehorses were not always selected for breeding, they said.

The genetic origin of the Quarter Horse dates back to the 17th century, when English mares were bred with stallions from present-day Saudi Arabia and Turkey.

The Quarter Horse has become one of the largest and versatile horse populations in the world. Their use in family outings, working with cattle, Western competitions and sprint races has been preserved since the formation of the breed.

The official start of modern sprint Quarter Horse races occurred in 1943 in United States, in Tucson, Arizona.

In Brazil, information about the beginning of Quarter Horse races is lacking, but zootechnical records date back to July 1978, in Sorocaba, São Paulo.

The trio sought to evaluate several traits through the results of heritability, genetic correlations and trends.

The data comprised a period of 38 equestrian years, from 1978 to 2015, with 23,482 sprint race records from 5861 animals in Brazil. They assessed earnings, best time and time class at distances of 301 meters and 402 meters.

The results showed that, when the researchers evaluated the earnings trait together with other important traits, the best values were observed.

The selection process for the best sires and dams should be performed through two straightforward stages, they said.

First, the animals that obtained the best times should be evaluated, and then the highest monetary earnings should be factored in.

The authors noted that their evaluation of the 10 years of data from 2006 to 2015 showed negative trends (genetic loss) and trends close to zero (genetic stagnation).

“Overall, this study emphasizes the lack of genetic response in recent years of the selection/evaluation of Quarter Horses bred in Brazil,” they said.

The decline in genetic response was confirmed by the absence of significant genetic gains for the traits analyzed, they said.

The earnings trait on its own exhibits genetic variability, they said, suggesting that including it in selection programs along with other racing performance traits may result in positive changes for the genetic trends.

“Quarter Horse associations, technicians and breeders must apply different strategies in selection and improvement programs that will allow for the genetic evolution of this population in conjunction with the monetary gains of the owners.”

The design of breeding programs using the earnings trait in conjunction with other racing performance traits had the potential to boost genetic gains as a whole in speed-racing Quarter Horses.

The design of breeding programs using the earnings trait in conjunction with race times could change the results observed and improve genetic gains for speed racing Quarter Horses around the world.

The authors said the lack of selection of horses with superior estimated breeding value – a measurement of genetic potential – impairs the evolution of the Quarter Horse breed. This, they said, was observed in the present study by comparing the estimated breeding values between non-breeding and breeding animals, and by the analysis of the genetic trends observed in the last 10 years

“Breeding animals should be selected based on the correct and precise evaluations of horses, and breeders should request the help of researchers in the evaluation and selection of breeding animals, thus ensuring phenotypic improvements in Quarter Horses, whose sprint race records have stagnated since 2009.”

Faria, R.; Vicente, A.; Silva, J. Racing Performance of the Quarter Horse: Genetic Parameters, Trends and Correlation for Earnings, Best Time and Time Class. Animals 2023, 13, 2019. https://doi.org/10.3390/ani13122019

The study, published under a Creative Commons License, can be read here.