Cats mating

Question
My cat(zoey) and my friends cat(garfee) are around 18 months old. They have been kept together on and off for the past year but have not been allowed to mate. Now I want them to mate. Zoey allows him to come close to her and she licks him. But when he tries to mount her she hisses and cries a lot.
I have kept them together for 2 days now and have noticed garfee mount her many times. he pounces on her almost all day.
Q. I wanted to know if this is normal or Does he mount her several times a day because he has not successfully done his job?
Q. Is all the hissing and crying done by zoey normal or is the harmful for her?(coz she kinda screams all day and night)
Q. how long should i keep them together to make sure she is pregnant?

Answer
Maggie,

Is Zoey in season?  If not, Garfee may still try to mount her, but she will not be accepting his advances.

Even if she is in season, she may not accept his advances until she is good and ready.  If she is not experienced, she just may not know what to do.  If he is not experienced, he may also have some difficulty.  If he does get her, you should hear Zoey let out a major, big time, throaty screech followed by some growling. After this she should roll around on the ground and he should be huffing & puffing. They usually would then stop to "clean up" and may or may not try again right away.

Some males will mount once a day. whereas some mount numerous times a day. Some will breed for a number of days, whereas some will just breed for one day.

We usually let them stay together for three days.  We begin counting from the second day they have been together. Domestic cat gestation is 63-68 days from the time they bred. More normal is 65-67 days, with 63 being a normal minimum. If by day 68, she does not give birth, it is off to the vet.

To know if she took, around day 19-21, her nipples should "pink up" and protrude somewhat. This phenomenon lasts a very few days, so you just have to keep checking. from day 19 to day 23 to see if she may have become pregnant.

The seasons and the requisite behaviors, noise, etc. are not harmful to Zoey unless she does not get bred. If she comes back into season after being bred, it did not take.

All the hissing, spitting, growling, etc. is perfectly normal for the female.  Most males are either quiet or will kind of trill to the female.

I hope this all helps.

Best regards... Norm.