Horrified vets were forced to put more than 100 horses to sleep and rescue 300 more after they were found living in appalling conditions.
Animal charities swooped into “one of the toughest and largest rescues of all time” to remove the 400 horses at the “deeply upsetting” site after receiving a tip off.
They were forced to crawl through knee deep mud and drenched fields to reach the badly neglected animals and rounded up more than 300 horses to remove to places of safety.
Sadly 100 more had to be put to sleep after their injuries were considered too serious to recover.
Other animals including sheep, geese and dogs were also taken away.
Horseworld, based in Whitchurch, Bristol, were among the charities who assisted the RSPCA in the rescue at the site in the Vale of Glamorgan, Wales.
“Not all of the horses counted in the field pulled through and over 100 equines had to be put to sleep,” Director of Welfare Jerry Watkins said.
“This decision was not taken lightly, but it became clear as the team assessed each horse individually that a number of the horses were in such a state of suffering that there was only one option for them.
“I am incredibly proud of HorseWorld and that we were able to support the other organisations involved.
“This situation is evidence that the equine crisis is worsening and could get worse as we go into what is predicted to be a very harsh winter.
“This is the most awful welfare situation I have faced due to the number of horses and resources involved.”
HorseWorld Trust, Redwings Horse Sanctuary, Vale of Glamorgan Council officials and the RSPCA spent over a week working together to assess the horses’ health following the rescue beteem November 12 and 17.
Alun Davies, the Minister for Natural Resources has commented that, “I am grateful to all those involved for their swift and effective action which has relieved the suffering of these horses and I would like to pay tribute to the Vale of Glamorgan council for their robust response to this emergency.”
The RSPCA dubbed it a: “tragic situation that was hugely upsetting for all those involved”.
A spokeswoman for the charity said it was an ongoing animal welfare investigation and they could not provide further information.