Regulations issued by the U.S. Department of Agriculture to prevent the cruel practice of horse “soring” are being challenged in federal appeals court, prompting the Humane Society of the United States to file a friend-of-the-court brief. The HSUS is asking the United States Court of Appeals for the Fifth Circuit to uphold the regulations, which require uniform mandatory minimum penalties for violations of the Horse Protection Act. The district court in Texas previously ruled against the plaintiffs and upheld the regulations.