Class = age/sex group for a particular kind of livestock, in this case cattle. Classes for sale cattle include the following:
Bulls: bull calf, weaner/weanling bull, yearling bull, 2-year old bull, mature bull, bologna bull
Cows: bred cow, open cow, three-in-one (cow bred with calf at side), cutter cow, canner cow, slaughter cow.
Heifer: bred heifer, feeder heifer, open heifer, heiferette, weaned heifer, heifer calf
Steer: feeder steer, dairy steer, steer calf
Weight is always approximate, rounded to 100 pounds (45 kg).
A word about breeds with large horns: Be aware that large horns mean an increased risk of harming yourself when handling the cattle, as well as intimidating other animals including horses. Be sure you want to own cattle with large horns; they look good but they’re harder to transport and to tether.