Complex sentence: Of his foals, 108 started races, and 77 won races, earning a total of $476,949, the most successful of whom, Lightning Belle, earned $60,134 ($as of).
Split into simpler sentences: Of his foals, 108 started races, and 77 won races, earning a total of $476,949. The most successful of his foals, Lightning Belle, earned $60,134 ($as of).