Burglars stabbed a horse 40 times during a raid on a stables in Sussex.
They smashed a window before attacking the two-year-old animal, called Duggan.
Owner Jenny Rogers was heartbroken when she discovered Duggan's injuries following the attack at Romanville stables, in Horsham Road, Steyning.
After treating Duggan and calming him down, she said: "Another owner got to the stables ten minutes before me and, as I drove down, she came running across a field in a bit of a state to tell me Duggan was upset.
"He is not nasty but he was certainly agitated.
"He was very flinchy, completely confused and upset and I was wondering what on Earth had happened."
Miss Rogers, 21, from Worthing, said: "The stables now have to be under 24-hour surveillance.
"Whoever did it, I would like to do it to them.
"They have come down here, frightened the life out of Duggan by smashing the window, done what they have and left him wondering who has done it and what did he do wrong.
"It's sick - someone has got some sort of problem."
John Edlin, owner of the stables, was installing CCTV cameras, alarms and spotlights yesterday.
He said: "We've been here 27 years and this is the first time anything has happened.
"I cannot imagine the mentality of someone who would do that."
The burglars jabbed at Duggan with a sharp instrument, leaving the horse with cuts all over his body.
Miss Rogers said she had nursed him through a bout of peritonitis and was very close to the animal.
The incident is believed to have happened after 11pm on Thursday.
Nothing was stolen from the stables.
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