We were looking at that breed as an option when we bought Princess (Schweenie)
My lil doggie goes into heat every 3rd month. I am gonna have to spay her. I like to let dogs be natural, but if the big boy gets to her in heat it could be bad!! She is 10-12 lbs and he is well over 100 lbs. Her heat is over again...whew!! They love to play and they never fight which is great. Ppl are surprised at the size difference in the dogs and worry about her, but he would never hurt her or anyone (on purpose that is) he does step on ppl and her sometimes when he is running. He is really clumsy sometimes. He knocked my daughter down one day when she opened the door to let him out. She had a concussion as a result of hitting her head. She still loves him though. He felt really bad and kept checking on her.
I am rambling...lol. Ill shut up now.