Complex sentence: Blue Norther (1961--1972) was an American Thoroughbred racehorse who, along with Tosmah and Miss Cavandish, was a top filly in United States racing in 1964.
Split into simpler sentences: Blue Norther (1961--1972) was an American Thoroughbred racehorse. Along with Tosmah and Miss Cavandish, was a top filly in United States racing in 1964.