Free rein to breed for horses enjoyed by the Queen
Cleveland Bays on the increase again after genetic tool tackles inbreeding
A HORSE breed favoured by the Queen has been saved from the brink of extinction with the help of a genetic analysis tool which prevents inbreeding.
Cleveland Bay horses were once a stalwart of English culture and heritage, used to pull farm machinery.
But after the end of the First World War, when they had towed artillery, the breed suffered a dip in popularity and numbers fell.
By the 1960s there were only a handful of stallions left in Britain. A young Queen Elizabeth II intervened and bought Mulgrave Supreme, one of the few remaining. The royal affiliation led to many stud requests, helping to boost the population.
Cleveland Bays are still closely tied to the Royal family, and are one of just two breeds — along with Windsor Greys — housed at the Royal Mews. While the Windsor Greys draw the carriages in which the Queen, other members of the Royal family travel, the Cleveland Bays perform all other royal equine duties, including pulling all other carriages and performing day-to-day activities such as the royal mail run.
Inbreeding has been an issue. By 1994, three per cent of the breed’s gene pool was being lost forever every generation and there was an effective breeding population of just 20 animals.
“This was a turning point: the breed could easily have become extinct if urgent genetic management had not been established,” said Prof Philippe Wilson and Dr Andy Dell from Nottingham Trent University, who created a way for breeders to avoid matching up closely related horses.
“The breed was already seeing signs of increasing infertility with it becoming increasingly difficult to get mares in foal and then to bring those that did to full term and produce thriving youngstock.
“There was anecdotal evidence of the occurrence of genetically related arthritic and respiratory conditions.”
If unchecked, inbreeding can lead to a high level of genetic diseases, shortened lifespan, infertility and deformities.
The researchers spent 16 years working on a procedure to allow for the safe and sustainable breeding. Their main tool came via the Cleveland Bay Horse Society, which has stud books dating back to 1885 and pedigree information stretching as far back as 1723.
This family tree contains more than 38 generations. The information formed the backbone of a Breed Conser
‘The system can be extended to any populaton with pedigree data so the potential is manifest’
vation and Management System (BCAS) which allows breeders to see how closely related two Cleveland Bay horses are, and if breeding should be stopped.
Every mare/stallion gets a traffic light rating based on their familial link and what the risk of inbreeding is. Green is encouraged; yellow is “best of the rest”; orange is discouraged; and red should be avoided “as they are highly inbred”.
The use of this tool proved effective. As of last year the effective population size was 171 and there are 100 purebred stallions globally, including 41 in the UK. The rate of inbreeding has fallen to just 0.5 per cent.
“The population is far more secure than before the work began,” the scientists said. “The breed is in a far more secure position.”
Other species and breeds face similar problems, and the BCAS tool could help them, the experts say.