At any stage you can get both neutered and this may help with this behaviour. It will also help reduce the chances of any interdog aggression and also the chances of cancer in the testicles.
As for the particular behaviour the best way to deal with these sorts of things is to reprimand the older dog when he does it. Use a large GRRRRRR or AHHHHH and throw a blanket over him or squirt him with a water pistol. This will reinforce what is the wrong behaviour.
Combine this by reinforcing the correct behaviour. When he stops mounting give him a sit command. When he responds praise him with attention and petting. This will help make things better.
We have just had our 14 month old boxer castrated but he hadnt shown any signs of mounting at all. We did it for health reasons and because there are a few unaltered females around the neighbourhood. BUT the only other dogs i have seen doing this is two chocolate labradors owned by the same person that go upto the field where we walk ours both unaltered and a chocolate lab of my friends he also does it and had tried to do it with my boxer a few months ago! Are there any particular breeds that are more prone to this type of behaviour or is it just when they reach a certain age???
Hi Debbie In my experience some breeds do seem a bit more prone to things like mouting and humping, many of the ones i have seen are labradors. But that doesn't mean it is always these breeds. Some dogs just develop the behaviour if it has been accidentally reinforced eg people laughing the first time it happens. This praises the dog and the problem can start from there. Other dogs just start it for no particular reason.
Whatever the reason reprimanding it is the best way to fix it
