A high profile Tennessee Walking Horse trainer – who was shown abusing his horses in undercover footage broadcast on ABC News – has pleaded guilty to conspiring to violate the Horse Protection Act (HPA).

The video was filmed by the Humane Society of the United States (HSUS), and shows Jackie McConnell beating the horses with wooden sticks and poking them with electric cattle prods.

Mr McConnell admitted to applying banned chemicals to the horses’ pasterns making them hyper-sensitive, causing them to raise their front legs artificially high – a practice known as “soring“.

He also admitted to trying to camouflage the signs of this practice, which has been illegal for more than 40 years.

Two other men – John Mays and Joseph Abernathy – pleaded guilty to misdemeanor charges related to the case, with Mr McConnell on 22 May. Sentencing will be held on 10 September.

“Although the HPA has been in place for more than 40 years, violators have seldom been prosecuted,” said the HSUS’s Keith Dane.

“The McConnell case urges the federal government to continue to make the enforcement of the HPA a top priority.”

The trainer has also been banned for life from the biggest annual event for the breed – the Walking Horse National Celebration (22 August – 1 September).