Cows are routinely sold for meat. Steers tend to bring a few more cents per pound than cows because they will fatten up faster in the feed lots.
More than half of the McBurgers you buy are old (and I mean OLD) milk cows.
On butchering in the driveway, I prefer a pulley attached to a stout overhead beam. Rope or cable winches the body up off the ground. Much easier to do neat, clean work.
I once read a magazine article on how efficient the beef industry had become .... they likened it to pork, where there was even a market for the bung.... next sentence they were saying that the number one beef bung customer was Korea until McBurgers came along.
Now that puts a new spin on a big Mac!
We used to use an old swing set for deer.