I'm not sure...but I never have the ram near the ewes ready to birth or with their lambs for at least 6 months. Rams can kill newborn lambs...almost had that happen with our first lamb born here before we knew it was a danger...he went after him, pounded him with his front hooves...we got the ram out and luckily the little lamb was okay. Never made that mistake again...sometimes learning the hard way is just too hard!
depends on what breed the ewe is, most hair sheep are out of season breeders and will breed back as soon as 4-6 weeks after birthing their lambs. Most wool sheep are seasonal and wont come into heat until fall, but I know there exeptions to that rule.
I keep my rams with the ewes, never had an issue with them bothering the lambs, only ones that worry me sometimes are the yearling boys trying to play with the 2 week old babies, but if that gets too rowdy the ewe gives them heck.