Simplify the following text for a Grade 4 native English-speaking person.
Original: After his racing career Lightning Bar went on to become a show horse , earning 18 open halter points with the AQHA , and an AQHA Champion award in 1955 .
Simplified: After Lightning Bar 's racing career , he went on to be a show horse . He earned 18 open halter points with the AQHA .