A horse owner has been left heartbroken after having to put down two mares who ate grass cuttings dumped in their field.

More than a third of local authorities in England have halted garden waste collection, leading to some people simply dumping it in rural back lanes.

While horses enjoy grass in moderation - such as when they graze naturally - gorging on large amounts means it ferments in their stomach and produces toxic substances.

Sarah Imamzade, who kept her son Sam's two mares - Paris,16, and Lady, 10 - near Aveley in Essex said she had no other option than to put them down.

The family have had the horses since they were born.

She said: “Two of our horses, Lady - a mare we have had for ten years since she was a foal - and another mare, Paris, we have had for 16 years,had really bad colic because of this.

“We got the vet out straight away, but it was too late, the colic was too bad and they were in such pain we had to have them put down.

"We felt completely heartbroken, shattered, angry, drained and we just felt destroyed.

"It's 16 years of our lives loving, caring, and protecting our horses for them to just be gone. It should not have happened.

"When you're stood there looking at her, so swollen and in pain, knowing there isn’t a single thing you can do to make her better, except make the call to put her out of her misery. Let me tell you, that feeling is horrendous."

Both horses had to be put down in the space of just four days, with Paris having to be euthanised on April 18.

Sarah and Sam made the horrifying discovery that Lady was in peril during a normal visit to the stables.

Sarah said: "Her stomach was so swollen and she was was on the ground.

“We struggled to get her up and walk her. As soon as we got her up and had her walking we called the vet out straight away.

"The vet got there, checked her stomach and her temperature. She then flushed out her stomach, removing two-and-a-half buckets of brown sludge.

"That is when she confirmed with us that she had been eating grass cuttings and that there was nothing she could do and the kindest thing would be to put her to sleep.

"She also said that she could operate on her and we could spend thousands trying to get her better but she wouldn’t survive it either way. She said if we hadn’t called her out, then by the next day her stomach would have ruptured."

Within four days Paris' condition also deteriorated and she had to be put down too.

Sarah added: “It’s a stables where lots of local people keep their horses in fields which are sectioned off.

“Ours graze in a section near the road and someone dumped a load of grass cuttings in the field over the weekend.

“What most people don’t know is that horses don’t produce a lot of saliva which breaks down grass. It’s OK when they graze normally but with likes of finely cut grass they gorged on it. It ferments quickly inside them and releases toxins that cause colic.

“We don’t think it was deliberate, probably just someone who doesn’t want to store their garden cuttings at home, but we don’t want it in our fields killing our horses. People shouldn’t dump things or even feed horses, it’s dangerous.

But despite trying to spread the word about the threat grass clippings pose to horses, piles of garden waste have still been appearing in the field.

Sara added: “On Monday we found another lot of dumped clippings that we were able to clear away. Please stop.”

Colic causes significant abdominal pain and is caused by a number of things, some of which can prove fatal without surgical intervention.

Among domesticated horses, colic is the leading cause of premature death. The incidence of colic in the general horse population has been estimated between 4 and 10 percent over the course of the average lifespan.

Clinical signs of colic generally need treatment by a vet. The conditions that cause colic, for example diet, can become life-threatening in a short period of time.

Colic surgery is usually an expensive procedure as it is major abdominal surgery, often with intensive aftercare.