Hi. I am debating at what age or if at all to have my pup neutered. He is a 4 month old border collie(too young at present I know).He is very submissive to people and dogs. My other dog is quite aggressive outside with other dogs but loves the puppy . I always exercise them seperately to avoid and bad learnt behaviour but am wondering wether neutering would be a good or bad idea.I brought Buddy the pup with the intention of doing obedience and agility with .Everyones opinion most welcome.Thanks

I have a Border Collie and he is a very submissive lad.  If it hadn't been for a retained testicle I would never have had him castrated.  I don't think there is any need to have your boy done.  They are so biddable and eager to please.

Unless it needs to be done for a good medical reason, I wouldnt get him castrated at all.
Your vet will probably frighten you by giving you scare stories of testicular cancer. This IF it happens at all, will not occur for a goodly amount of years & most of the ones I have heard off havnt got until old age (10+ years).
If he is a submissive dog already there is less need anyway. I would suggest to assess the situation in a years time as even if a dog had a retained testicle(not that you say he has), I would do anything until well after a year old.

Your right to walk your 2 separately for 2 reasons, firstly for the reason your doing it. I did the same with my young ones & it does work. Secondly your pup will need a different amount of excercise than your other dog(you dont mention an age), for quite sometime yet.

As he is very submissive I would NOT get him neutered.  OTT submission is often a sign of nerves - my own collie pup is the same around dogs and it's definitely nerves with her.  With boys, being entire can give them more confidence via the testosterone so neutering can do the opposite, making a mild issue or even a non-issue into a major problem.  I've seen it enough times to be extremely wary - a friend of mine had her husky/mal PTS last year after several years of trying overcome the devastating effects of being neutered.  He went from cautious to extremely stressed and nervous and very aggressive.  I'm not having my girl neutered until she's at least 2yrs old (fully physically and mentally mature) for the same reason, as a similar thing can happen in bitches and when she is ready physically and mentally, I will be reassessing based on how she's doing behaviourally.

Meantime, work on his confidence: keep meetings with other dogs extremely short, seconds at a time, moving him on and keeping it happy before he gets a chance to go all appeasey as it is very self-feeding - the more he appeases the more other dogs will respond to it, some negatively (it is annoying for the dog being appeased when it's very OTT), and that will make him want to try and appease them more.  So short and sweet, and reward anything calm and confident - I have been rewarding Willow simply for staying on her feet near other dogs, and moving her away when she starts her uberwiggles or trying to flop or grin (grinning is appeasement also).

With people - if he is going very submissive and trying to flop on his back, try not to let them stroke him - it means they'll be leaning over which is scary for a dog, but more so for an appeasey and/or nervous one.  Same as with dogs - short and sweet, and reward for calm and confident.  If people are very insistent, tell them to crouch down so they aren't as threatening (and I do mean tell!  If they won't, walk away).

I don't think there is any need to have your boy done

Totally subscribe to this!!    I have only resorted to castration for medical reasons.   I'd certainly not consider this unti the dog is over a year old, by which time he's had a chance to mature a bit, and the owner to make this decision, which is surgery afterall, however simple, and not reversible.   I spayed my bitches, usually on being retired, but not my males.    And this was because not only is there enough evidence to persuade me that female cancers are more likely to happen with unspayed bitches (also pyometra) but I didn't see any need to confine my girls, twice a year for 21 days.

A friend has just had their boy neutered - at the grand age of 15 !

He's in great shape, fit and healthy, but developed a tumour on one of his testicles, so they had them whipped off.    He's doing great :-)

Really, I would never have a male dog neutered except when there's a lump detected.

For a retained testicle I would have the retained one removed and leave the normal one.  

If a testicle causes a problem, it can easily be detected and dealt with - and they need those hormones :-)

http://saova.org/articles/Early%20SN%20and%20Behavior.pdf

The title says it all:  Non-reproductive Effects of Spaying and Neutering on Behaviour in Dogs