Water weighs 8.34 pounds per gallon, if your steer had not drank prior to weighing him, and then drank before you weighed him the next time 10 galloons could make a 80+ increase, We always weighed the same time of day (Sunday evening) to try and get a consistent weight. Prior to fair when we were trying to hit a weight we would weighed a calf first thing in the morning and then in the evening after he had been in the barn tied all day, they cold drop 60 pounds in 12 hours. In about an hour they picked it up again after eating and drinking.