how do i know when my dog is ready to mate

Question
QUESTION: Hi I have a 14 month old shih-tzu she stopped bleeding and she was with 2 males one of them kept right at her sniffed he licked but she would not let him mount her later she started bleeding again she was swollen and had a good size opening then later it got smaller and she started to bleed
help

ANSWER: Hi Brenda. I'm not sure what the question is here, but I have a few of my own.:-) How long was she in heat? What exactly is happening? Give me as much info as you can.:-)

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QUESTION: Hi I guess what I'm asking is how long does it take after she has stopped bleeding she had her period for 7 days but when it stopped i took her to 2 studs 1 was very persistin
and the other 1 was'nt. she let him lick her and sniff her and I meant he stuck right to her,then she would stand lift her tail and as soon as he out his paw beside her she would snapp at him.he tried to mount her and then she would growl and snapp.Should they be left in a room together or supervised thay are purabreed shit-tzu

Answer
Most breeders try on days 11 and 13, or on days 12 and 14 of the heat cycle. This is when most females are ready to be bred. I'm not sure what day she is on now, but if she's still too early, she won't let the male mount her. If she is in the right part of her cycle to be bred and is still acting like this, then you may need to take her to the stud, and you either leave or stay in the house. Sometimes some petted females refuse to be bred with their owners in sight. Some females refuse the male you pick out. You may have to end up using A.I. if you truely want this girl bred. You said that she's 14 months old. That's still pretty young. If she were my dog, I'd wait until her next heat cycle, and try again. She may just need to finish maturing. As for leaving them alone, not a good idea. They could seriously hurt each other. When breeding dogs, they should always be suprivised. Good luck!