In Goblet of Fire, Rita Skeeter reveals that Hagrid's mother was the violent giantess named Fridwulfa. While he's ashamed and hiding in his hut, Dumbledore tells Hagrid not to worry over embarrassing family relations:
"My own brother, Aberforth, was prosecuted for practicing inappropriate charms on a goat."
Later, in Order of the Phoenix, when Hermione sets up a sign-up for Dumbledore's Army, they hold their first meeting at The Hog's Head in Hogsmeade since they want to avoid being overheard. When they first enter, Harry observes that the bar was dingy and "smelled faintly of goats."
— Quora user Sandra D. Wu