We have found that it varies depending on wether the calves are for market or show, an the condition of the cow. We usually wean around 6 months, or enough time to give the cow a break before her next calf. If we are showing the calves, we get ready to feed them really hard when we pull them off. I have friends that wean at 4 to 5 months, and some that wean at 8. Just depends. There's many different ways, and we just found what worked for us.