When does a dog or cat first go into heat?

Most dogs will come into their first heat between 6 and 12 mos of age; smaller dogs sooner than larger dogs, generally.  Heat cycles usually occur every 7 to 8 months.  Most cats will come into heat between 7 to 12 months of age, however, some have been known to come into heat as early as 5 months of age.  Cats will come into heat multiple times per year.

How early can I spay or neuter my dog?

Most female dogs can be spayed by 5 months of age.  Male dogs can be neutered by 4 months.  See the Benefits of spaying and neutering.  See, also, Spay FAQ.

How early can I spay or neuter my cat?

Our rule of thumb is that a cat must be at least 4 lbs and 4 months of age to be spayed or neutered.  See the Benefits of spaying and neutering.

4.

My dog is pregnant.  Now what?

Look here for Care of your Pregnant Dog and here for Birthing Puppies.

5.

My cat is pregnant.  Now what?

Look here for everything you wanted to know about cat reproduction, pregnancy and birthing.