Welfare advisers from The Donkey Sanctuary are joining officers from the RSPCA in their annual visit to Appleby Horse Fair (8-14 June).
The event represents the RSPCA's biggest deployment of staff and the biggest multi-agency event of the year, with six other horse organisations also involved.
The traveller fair starts in the Cumbrian town on General Election Day and finishes on Wednesday.
This year, 33 RSPCA officers will be attending during peak times including specialist equine officers from across England and Wales.
RSPCA chief inspector Rob Melloy said: “Every year we learn lessons to take into the next. Last year the number of horses being worked to exhaustion was a big issue. Working an equine repeatedly over several days, even though it may appear to have recovered, has an accumulative effect. We often see different people with the same animal who may not be aware of how much work it has done that day or on previous days at the fair.
“We’ll be using exhaustion tests on horses we’re concerned about, which were developed to be used on horses ridden in endurance events. A man from Essex was jailed after being found to be working an exhausted horse at last year’s fair. I’m urging people to be vigilant and report anything that concerns them. We often get calls after the fair but very few during. Fair-goers can approach our officers - or those from the other horse charities attending - on the ground or they can call us on 0300 1234 999.”
There will be seven people attending from Blue Cross, four staff from Bransby Horses, a vet and two donkey welfare advisers from The Donkey Sanctuary, three vets, two senior field officers and an education and campaigns manager from Redwings Horse Sanctuary and four field officers and one welfare support officer from World Horse Welfare.
As always, there will be a vet station at Salt Tip Corner where assistance can be sought for any animal that needs it. The vet station will be staffed on Friday, Saturday and Sunday (9-11 June) between 10am-4pm.
Education staff and volunteers from all five of the animal welfare charities - all members of the National Equine Welfare Council - along with The British Horse Society - will also be manning an information and education tent on Salt Tip Corner where Gypsies and travellers can share knowledge and discuss issues relating to horse care.
Now in its seventh year, the tent continues to grow in popularity thanks to interactive activities including specimens of real horse parasites and body condition scoring.
The RSPCA will be tweeting from the event - follow @RSPCA_Frontline and @DonkeySanctuary for updates.