Most people out here go between 90 and 120 days, but they clip them tight about 10 to 20 prior. At 90 days they go in from 5:30 am until is dark, if we have a heat wave they stay until the temp goes down as well. My buddy can get North Dakota type hair on them in about 90 but they put a ton of work into the animal, rinse in the morning, then after school the kids rinse with water for about 10 minutes then with ice cold water for 5 more, them spend about an hour per calf working the hair, at about 7 they work the hair some more, (they rinse in the cool room). All in all they spend about 3 hours a day on each calf.