Complex sentence: In this sense of the term, father/fatherly is non-suppletive-- "fatherly" is derived from "father"--while father/paternal is suppletive, and likewise cow/cowy is non-suppletive, while cow/bovine is suppletive.
Split into simpler sentences: In this sense of the term, father/fatherly is non-suppletive. Likewise cow/cowy is non-suppletive, while cow/bovine is suppletive.