Wiktionary gives the etymology of "bó" as coming straight from Proto-Celtic and Proto-Indo-European. In any case, sometimes Irish has both a word of Celtic orig

Wiktionary gives the etymology of "bó" as coming straight from Proto-Celtic and Proto-Indo-European. In any case, sometimes Irish has both a word of Celtic origin and a loanword for animals. "Chicken" is "cearc" but also "sicín".