Hello. We have a much loved and fairly dog-grumpy Border Terrier Rosie. She's nearly fourteen, has had a lymphoma diagnosis for almost six years, but is still resolutely with us and defying the prognosis. She's slowed down a lot, almost blind, getting deaf, but with a nose like nothing on earth and still comes for a toddle round the block.
When we brought Bonnie home last year, we introduced them in the garden, put Rosie on a leash for control and left Bonnie off leash. Bonnie's manners were excellent, she greeted Rosie respectfully and didn't get rambunctious until they'd spent some time together. I was amazed at how straightforward it was (Rosie has a chequered history!). I don't know if the way we did it was 'technically' correct however, given I knew the puppy wouldn't start a fight and that I needed to have some control over the old biddy, it worked really well. I think if I was to get another spaniel (so tempting), I'd do the same thing. Bonnie on leash and the puppy off.