If you were from Bavaria, as many American immigrants were in the mid 1800s, it wouldn’t be at all strange if when you thought of goats you thought of beer. And vice versa.
First brewed in the dark ages of 14th century Germany in the town of Einbeck, Bock beer was a dark, malty, lightly hopped ale. Brewed and consumed exclusively by Bavarian monks, Bock was an obscure beer back then. The monk’s apparently needed their Bock to give them the essential nutrition they required during times of fasting. So it was that Bock bacame associated with religious festivals; Christmas, Easter and Lent (which became known as Lentenbock). No goats yet.
Munich brewers stole the monk’s recipe in the 17th century and adapted the beer by using a new-fangled style of brewing they called “lager”. Due to their Bavarian accent, the citizens of Munich pronounced “Einbeck” as “ein Bock” (a billy goat), and so the beer became known as “bock”.