Longtime owner, breeder and trainer Robert &ldquo;Bun&rdquo; Colvin died Saturday at Avena Queen of Peace Hospital in Mitchell, S.D., after suffering a heart attack. He was 74.\r\nColvin campaigned his small string of horses primarily in Minnesota in recent years. He was also a frequent visitor on the Nebraska circuit during the days of Ak-Sar-Ben and raced throughout the Midwest. His homebred Plana Dance was a multiple stakes winner at Canterbury Park in the late 1990s, winning the Canterbury Oaks in 1996. She also captured the Princess Elaine Stakes in 1997 and 1998 while earning over $170,000 in her career.\r\nColvin, from Alexandria, S.D., is survived by his wife of 56 years, Marlene, and two brothers. Funeral services are set for Wednesday at Will Funeral Chapel in Mitchell at 1 p.m. Burial, with military rites, will be at Greenhill Cemetery in Alexandria.