Is this aggressive behaviour or just male dominance?!

Hi all, just a quickie, TJ really is the softest dog you'll meet so soppy, but last night i saw a side of him that i didnt like one bit!
He is a 17 month entire border collie.

My boyfriends mum has just got a new collie puppy she is 14 weeks, TJ was in the garden when the puppy came over to him, first off he was sniffing then, he growled and pinned her to the floor he didnt bite, just stood over her looking really horrid, hackles up, teeth showing, puppy was lying flat, not moving.

my boyfriend just pulled him off and told him off, stern NO, and we seperated them.

Im confused ive never seen any aggressive behaviour in him, is it just a dominance thing, or just plain aggression?? help please, and also suggestions on how to get them to get along...!

Would think he was just letting the pup know where it stood in the order of things, as the pup was unharmed the job was done properly. Of course, watch him in future but I would not intervene unless the pup was in danger of being harmed, sometimes it is difficult for us mere humans to realise that there is no aggression involved just body language being used to communicate.

PS sometimes dogs (males) are a bit worried about puppies and it takes them a while to decide how to deal with them. Just make sure the older dogs can escape if they wish.

many thanks for your replies, it just worried me as ive never seen tj act like that before, i guess as cute as pups are to us, they can be quite daunting to adult dogs!

I agree with what has already been said Gems. I wouldn't worry too much - a lot of adult dogs just don't know how to deal with tiny pups. I wouldn't intervene unless you have to and I bet by the time the pup is six months old they will all be best buddies

I agree with older male dogs being worried by pups, when we got Star Storm would not even come in to the same room as him and when he plucked up the courage he just barked at him that he lost his voice much to the vets amusement, Jake on the other hand did almost the same thing as your TJ but we let the get on with it and said we would only step in if it went to far which it never did and when Star got older all 3 were inseparable

many thanks everyone, you've put my mind at rest