Problems with toy possessiveness .

Question
Hello! I adopted my dog Brody last August. He is an eighteen month old huge Golden-Irish. I take him everywhere with me. Including out to our family farm where there are two other dogs. Before when I've taken him out there he has been perfectly fine with the other dogs. If I take him to my mom's he's been ok with her dogs. Even with sharing toys. A month ago I had him out at the farm and he found a chewy bone. He chewed on it for a bit then went on to something else. Well another dog decided to try out the bone and he flipped out. There was a huge dog fight and Brody acted like I've never seen him act. It really scared me. I have two cat's at home and Brody will chase them when they get around his chewy bones or toys, but I just fingered it was a cat/dog hatred thing. He also get's really possessive over my food. If I'm eating at the table he sits as close to em as he can and chases the cats off if they come near.

Then last week I took him over to a friends house who has a little terrier mix, Django. Brody discovered his toy basket and decided to play with a ball. Knowing what happened last time I took the ball from him right away and proceeded to hide the rest of the toys. Before I knew it Brody started growling and had Django by the hind quarters shaking him. I got them apart and scolded Brody. Django didn't get hurt luckily.

I'm at a loss with what to do with him. I like taking him to family functions, but if these dog fights keep continuing I can't.

Answer
Unless he is possessive of his things with humans, this is a management issue for the most part until you get some professional help with training and behavior modification.  For now, you should not place your dog into situations where he will feel possessive over toys or food, so don't leave those things in the environment when your dog is there.  Your very first step should be to have a positive trainer assist you in teaching your dog some basic skills, such as "leave it" and "take it" as well as a proper recall and other basic obedience.  Corrections tend to make the guarding problems worse.  The dog is already fearful that someone wants "his" possessions, then they confirm it for him by taking them and following up with being stern.  counterproductive, in my opinion.  If you need help finding a trainer to work with you, you can start by contacting one through Truly Dog Friendly, Karen Pryor Academy, Academy for Dog Trainers, Pet Professional Guild, or Victoria Stilwell Positively.  The trainers on those lists will handle your pet humanely.