The RSPCA said there were almost 600 convictions for cruelty or neglect of horses, donkeys and ponies last year, two-and-a-half times more than in 2011.
The animal welfare charity investigated almost 3,000 more complaints of animal cruelty and neglect in 2013 than in 2012, although overall convictions were down on the previous year, new figures showed.
But there were 585 convictions for cruelty or neglect involving horses, donkeys and ponies last year, up from 500 in 2012 and an increase of 154% on 2011's figure of 230, when the RSPCA warned of an equine crisis.
Cases included Bluey, a young mare who was found in an emaciated condition with her dead foal lying nearby, and Molly, a piebald filly who was emaciated and collapsed when she was found, but who after intensive care went on to win reserve champion in the Rescue Horse of the Year Championship at Equifest 2013.
In total, there were 3,961 convictions in 2013, down from 4,168 in 2012.
The number of individuals convicted also fell last year, from 1,552 in 2012 to 1,371, the charity's Prosecutions Annual Report showed.
There were convictions in cases such as Rocky, a cross breed who was shot in the head five times, hit with a shovel and left to die in a ditch - although he miraculously survived - and shih-tzu Florence who was so badly neglected her paws fell off.
Other cases investigated by the RSPCA included dogs being set on wild animals and a shar pei dog called Ruby who was kicked, punched and dragged along a pavement before she died.
– David Bowles, head of external affairs at the RSPCA
Whilst we are heartened that the numbers of people convicted of cruelty have decreased, the fact that we are investigating more and more complaints shows that there is still a culture of cruelty out there.
Nothing illustrates this like the massive increase in equine-related convictions.
This is due mainly to irresponsible owners who have let their animals breed indiscriminately, together with an economic downturn which has seen feed prices go up and horses going for just a few pounds at market.
As a result, horses have been left to suffer without food and vet treatment.
- The RSPCA rescued an increased number of horses in 2013, up from 1,275 in 2012 to 1,797 last year. The charity also rescued 17,665 dogs
- The RSPCA rehomed 55,323 animals last year, it said.
- Dogs are still the most likely animal to be involved in cruelty cases, with 2,505 convictions related to dogs, a slight decrease on 2012's figure of 2,568
- The RSPCA investigated 153,770 complaints of cruelty last year, an increase from 150,833 the previous year
Mr Bowles added that although there had been fewer convictions relating to dogs, the charity was still rescuing more and more.