Per the AKC, the dam must be at least 8 months old; however we recommend waiting until she is at least 2 years of age
which allows her body to mature before going through the stress of pregnancy. Females are normally retired from breeding by the age of 7 years old (though the AKC will register a litter from a dam up until the age of 12) and your veterinarian may recommend a much earlier retirement based on individual health.
She can continue to enter heat
until she is in her teens (and sometimes for her entire life). As soon as you know that you will not breed her anymore, you should have her spayed. This is very important for her health.
Male Beagle dogs should be at least 9 months old; with the 1 year mark being preferred to ensure good, viable sperm.
Both dogs should have full medical checkups and be cleared as dam and sire. This will check for genetic issues that can be passed down to puppies. You will want to make sure that both dogs are healthy and that both dogs do not carry any hereditary diseases that can carry through bloodlines. Testing should include hips, CERF, elbows, CCD, and thyroid.