An American study hopes to determine whether genetic or environmental factors are more important in the durability and longevity of Standardbred racehorse careers.
The project is a collaboration between the US Trotting Association and Dr Doug Antczak’s laboratory at Cornell University’s Baker Institute for Animal Health.
The project involves up to 300 horses, including younger racehorses that will serve as controls, focusing on Standardbreds with long and successful careers — the so-called “iron horses” of harness racing.
Other veterinary scientists from Cornell, the universities of Illinois, Kentucky, and Minnesota, and the Racing Medication and Testing Consortium are also participating.
The study team includes geneticists from the Horse Genome Project, veterinary clinical specialists, epidemiologists, and computational biologists.
“The aim of the project is to determine whether genetic or environmental factors are more important in durability and longevity of racing careers of Standardbred horses,” Antczak said.
“The question is highly relevant because the answer may help reduce racing-associated injuries and contribute to equine welfare in the harness racing industry. This would be good for the horse, good for the owners, and good for the harness racing industry.”
The first step in this study was to develop a list of horses that have raced for a minimum of five years. The US Trotting Association database was instrumental in this phase of the project, revealing more than 6000 horses that achieved this. About 75 percent of the horses are pacers, and the remainder, trotters.
As expected, most were geldings. Successful racing stallions and mares are usually retired early from competition for breeding.
The horses were then ranked by earnings or number of race starts, and separated by gait.
In the northern spring, the researchers began contacting trainers and owners to enrol selected horses in the study, with the only sample required for the study being a small quantity of blood for DNA analysis.
The selected durable horses will be compared with an appropriate control group using molecular-based testing that can identify genetic differences among individuals at 640,000 locations spread across the DNA sequence of the horse genome. Computer programs are used to analyze the large data sets produced in projects of this type.
The data will be evaluated in association with race records and other information about the horses contained in US Trotting Association databases.
Subsequently, full DNA sequences will be obtained from a small number of Standardbreds with long and successful careers in a bid to pinpoint regions of the genome responsible for durability traits.
The work is supported by a research grant from the Harry M. Zweig Memorial Fund for Equine Research at Cornell University.