Q: How should I introduce the puppy I'm bringing home soon to my 8-year-old golden retriever and get them to be fast friends? --N.P.
A: Both dogs will be vying for your affection, and any problems will probably be the result of jealousy. During the first few weeks, don't change the routine of the older dog; the younger dog is likely to be more amenable to change. Be present when they are together, and play with both of them, deferring to the older dog's needs. Feed them at the same time but not in the same place. If your older dog has developed a fondness for certain play activities, continue to put aside time for that. Encourage them to play together, but also provide time for the puppy and you to play alone. When you are not at home, keep them separate so that each can have its own territory.
Supervise their play periods even after the puppy has gained size and confidence. Exercise both dogs every day; that reduces the undesirable behaviors that result from boredom.
You can allow mildly aggressive behavior, such as growling, interfering only to prevent either dog from being harmed. But should fighting or territorial marking become a problem, neutering or professional assistance from an animal behaviorist may be needed.