I have a 22-month-old Boerboel female. She was spayed about 2 months ago. She has suddenly started growling and snapping at people she knows and even growled at me once. She will come up to people and sniff them and even sits by them and look for attention from them and then if they try to pet her, she will suddenly look fearful and growl and snap at them. She has never been ill-treated in any way and is usually very loving. She is very doted upon and receives a lot of love. We got a daschund puppy about 6 months ago and we do not know if this could be a reason for her change in personality. The two get along well though and she is generally very gentle with him. She has even growled at me once and she is usually very protective of me, so I was very taken aback when she did that. She has a bit of a nervous disposition. I do not know if training will help in this situation. I am looking for advice and perhaps someone who can come and assess the situation. I have 2 children who often have friends over and I am concerned that she may bite my children or one of their friends.