when does a bitch become to old to breed?

The Kc will not register a litter from a bitch aged 8 years.

thanks polly, what age do you retire your bitch at?

in my breeds Code of EThics it states a bitch whould not ahve a litter before 2 years of age and not ahve more than 4 litters in her lifetime.  In practice most breeders will wait until nearer 3 years and will not breed from a bitch after 7, and few would have teh maximum 4 litters.

In my breed bitches shouldn't be mated before they are two, and not not whelp after the age of 8. The first litter shouldn't be much after the bitch is 4, and it's ideal to leave 2 clear seasons between litters. Most bitches have no more than 3 litters maximum, though a few have 4.

Bitches don't have a menopause, if that's what you mean.

One of my girls had her 3rd and final litter in December, she will be 6 in May............I think that is more than enough!

Thanks for your replies they have been a great help.