Ruminant Farmers always ask “At what age is best to buy ruminants one intends to raise”? Well the best time to buy them is usually after they are weaned. For cattle, I will recommend any time after 6 months, for sheep and goat, they can be purchased anytime after 2 months.
However, if one is interested in buying adult animals especially those that have been giving birth before, one must take time to know why the farmer is selling and the reproductive history of the animal in question. This is because a farmer hardly sells off adult and productive animals unless there is a problem.
See also: The Reproductive Rate of Sheep and Goat