Spider cows were used as livestock and their milk was consumed. While they were herbivorous, they were known for violently gumming other animals to suckle out moisture. They were also capable of shooting silk from their posterior, which Brad Boimler called "butt webbing." Stunning a spider cow could cause its milk to sour. Their oral slime contained an antiviral agent that protected local lifeforms from a virus causing uncontrollable rage in humanoid species.
They were housed in structures that presumably acted as barns with an enclosed gate of metal bars, though they were known to be strong enough to tear the gate apart if riled. During the day they would also be allowed to roam near their owners as the farmers worked their fields. (LD: "Second Contact")