A Nebraska man who promoted his ranch as being a haven for mustangs has been found guilty of 145 counts of felony animal cruelty.
Jason Meduna was found guilty by a jury and faces sentence on February 23.
Meduna ran a property called 3-Strikes Ranch in Morrill County.
Its website described it as a "Mustang outpost ... a habitat to hundreds of mustangs from all over the United States ... a natural environment for wild horses to run on the open prairies of the Sand Hills."
Some of the wild horses captured by the United States Bureau of Land Management that were not adopted after three attempts - called three strikers - were sent to Meduna at 3-Strikes Ranch.
Authorities and equine welfare groups removed more than 200 horses from the property last April. They became known as the "Nebraska 200".
The animals were legally surrendered to horse rescue groups Habitat for Horses and Lifesavers Foundation in an agreement co-ordinated by the Morrill County Sheriff's office.
The Humane Society of the United States applauded the jury's verdict.
"This was one of the worst equine neglect cases we've ever seen," said Keith Dane, the society's director of equine protection.
"While there is no restitution that can make up for the loss of life and severe suffering at the hands of this animal abuser, we are glad the jury's verdict recognised the cruelty inflicted by Meduna," he said.
"Hopefully, this case will send a strong message that this sort of animal abuse will not go unpunished."
The society assisted law enforcement and other horse welfare groups with the removal of more than 215 animals from Meduna's ranch.
When the property was raided, mustangs were found to be living in crowded, filthy pens. The horses were severely emaciated and were suffering from overgrown hooves and other untreated medical conditions.
In addition to the live animals, more than 75 horse carcasses were found on the property.
Meduna had acquired most of the animals from the Bureau of Land Management, some for as little as $10.
The animals were wild mustangs and burros rounded up through the bureau's wild horse management programme.
Following the seizure of the animals, the society provided emergency sheltering, care and logistics support. The horses were placed with qualified individuals and horse welfare organizations across the country.
Many of the rescued horses are being rehabilitated and trained by the Grace Foundation of Northern California. Several are currently available for adoption.
Interested parties can visit thegracefoundationofnorcal.org.
Meduna faces up to five years in jail and fines on each count.