HORSES are beginning to suffer the same kind of “extreme breeding” that has led to health problems in dogs and cats, vets claim.

UK animal experts warn the animals suffer lifelong medical problems as breeders pursue a “visual ideal”.

Visual records document the extent of the physical changes to hit long-established breeds in around 100 years of selective breeding.

The bull terrier’s skull shape has changed, leading it to develop extra teeth and the squat and heavy English bulldog suffers breathing difficulties.

The French bulldog cannot reproduce without human interference and most litters are delivered by caesarean section due to physical limitations.

Meanwhile the more modern Scottish fold cat, which has small, floppy ears and developed in the 1960s, has a cartilage mutation that causes lifelong painful conditions.

The problems are so acute that, despite the popularity of the variant with stars like Taylor Swift and Ed Sheeran, there are calls to end the breeding of Scottish folds altogether.

Now experts in the specialist Veterinary Record journal say they have discovered the first example of this sort of breeding in horses.

The concern surrounds images published online of a nine-month-old purebred Arabian colt named El Rey Magnum by a specialist farm in the US state of Washington.

The animal is notable for its concave skull and one vet has confirmed the horse had no medical issues or respiratory issues.

However, with the breeders responsible describing it as “a stepping stone to getting close to perfection”, British Equine Veterinary Association president Jonathan Pycock said the horse represented a radical variation on what was normal.

He further warned the nose structure “could put the horse at risk of breathing problems”, while Dr Madeleine Campbell of Equine Ethics Consultancy said: “Any trend towards breeding for extremes of form which might adversely affect normal function must be condemned, on welfare grounds.

“This would apply equally to head shape which might compromise the ability to breathe or eat normally or, for example, to extremes of animal size which might compromise the ability to give birth normally.”

UK equine expert Tim Greet acknowledged that a “dished” face is common to Arabian horses, but said this example “takes things to a ridiculous level”.

Comparing the situation to dog breeds affected by similar skull changes, he went on: “Dogs like man can mouth breathe, but horses can only breathe through their nose. I suspect exercise would definitely be limited for this horse.”

Publicising the horse on social media, the breeders responsible for the animal praised its “enchanted beauty”.

Earlier this year Veterinary Record announced a ban on adverts using flat-faced dogs like pugs, and a review of the use of images of the Scottish fold cat.

On the horse issue, its editor Adele Waters said: “My first thoughts were ‘is this the work of CGI?’

“Many specialist horse vets have had a similar reaction. But the truth is this is a real horse and it has been bred to meet the demands of a particular market that likes a particular appearance. Where will it end?”