The same as any other dog breed.
About 2 months: 60-64 days.
Why? Is your dog pregnant? If you have a pregnant dog and you don't even know the dog's gestation period, you have no business breeding it.
I work in a Humane Society, where we deal with 200 dogs every day who have been abandoned because their owners didn't have their dogs fixed.
It's so terribly frustrating for people like myself who strongly believe in spay and neutering, and adopting shelter dogs that are homeless because of careless breeders, and 'accidental' breeding
You really should keep an eye on your dogs at all times if they are not fixed.