We avoid any problem by letting the ewes do most of the weaning themselves. Our lambs are born in April, we take out any uncastrated males at 4 months, then finally separate the rest in September, by which time the ewes are winding down their lactation. This leaves two months for the ewes to get back into condition before tupping time comes round again in November. Obviously we watch the ewes for signs of problems but have never had any.