The Dartmoor Pony is a wild horse that lives in south-western England and there's been a recent population explosion.
It is a semi-feral pony which means that they're basically wild horses but they have contact with humans and have learned to tolerate them whether it is occasional feeding, medical care or just crossed paths.
These ponies have been breeding like crazy recently with many of them ending up in sanctuaries or at the slaughterhouse.
So vets working with World Horse Welfare have partnered with the drug company Pfizer to bring contraceptive injections to the ponies.
"A project of this kind has never been carried out before in the UK and I am delighted to be a part of it.
We are hoping that, if successful, this could become a long-term solution to the issue of overbreeding within Britain's semi-feral horse and pony populations."
It should be much easier, cheaper and less invasive than actually sterilizing the animals.
"We feel that this method of control is advantageous as the mares can come back into foal after the treatment; its simply means there is simply a reduction in foal production for the duration of the project.
We are close to starting the initial injections now that we have the [drug] in our possession and after the Veterinary Medicines Directorate gave us the go ahead for batches to be imported from Australia into the UK."
After a 6-month period the mares will be tested to make sure the drug is effective and if so, they will receive another injection that will keep them sterile until spring of 2013.
The secretary of the Dartmoor Hill Pony Association said:
"Controlling the production of unwanted foals will ensure the ponies' welfare. We are optimistic that this project will help us to ensure the future of ponies on Dartmoor, grazing to keep it as we know and love it for generations to come, creating the habitat for its wonderful birds, plants and animals to be conserved."
Let's hope this works to slow down the pony explosion because it's never a good thing when you hear the words "pony explosion."