Well, thanks to the internet, I now know that answer.
There are three terms used for a male dog:
- Stud - usually only used for breeding purposes
- Sire - but only if it has fathered pups
- Cur - although this usually implies one that is angry or ill or abused
And while on the subject, I was able to find out what male and female cats are called. Until now, I only knew the first of the following:
- tom - a male cat
- gib - a male cat that's been neutered
- queen - a female cat (usually only if she hasn't been spayed)
- clowder - a group of cats
And now you know too.