Grandpa used to describe the size of everything in terms of a calf. For instance, if he was describing a large dog, he would say it was 'about as big as a calf.' Or about a car, he would say it 'could seat four calves comfortably.' (Oh, that was another thing: how many calves could ride in something?) One time he was talking about a calf he had, and I asked him how big it was. He said it was 'about three-quarters as big as a calf.' Sometimes Grandpa would tell time by calves. If you asked him how long something would take, he'd say 'About as long as it takes a calf to drive over here.'
So... about as much as a baby calf weighs.