Also Motivated Grammar:
[Update 07/13: Anndra in the comments noted that Scots use the word beast as the genderless singular of cattle. This reminded me that there is a word that is specific to a bovine animal and is genderless and ageless: neat, as in neatfoot oil. Unfortunately, beast is of limited geographical reach, and neat is archaic, although I might try to adopt one or both into my lexicon all the same.]”