I have a westie and have decided not to castrate him as hes never let out alone so can't get into trouble but a friend got a bull mastiff and got her done before 1st season as this will give her better health.  I thought it was better to leave them but she says it prevents cancers etc now i am thinking about getting him done if it improves his health any advice greatly received don't want to risk surgery and discomfort on him if not necessary 

Hi guest!  This can be a very long and sometimes debateable subject - I suggest you use the search facility here on champdog's about neutering/castration and really weigh up the pro's and con's as you see it..Being the owner of a dog you may want to consider straying, dominance, marking and health issues (ie: cancers) - You dont mention his age but you may have all this to come!?  Then again I could say "if it aint broke, why fix it"?  I own a bitch who will remain un-speyed but I have made my decision based on information available to me...It really is a personal choice so research thouroughly!!
Sarah

IMO there is a chance that removing a large part of your dogs hormonal system will cause problems at some time in his life, and the younger it is done the more likelihood there will be that he will be affected. This opinion is formed on research done after some unfortunate experience with both mine and others dogs. And yes, you can't get cancer in the part that has been removed but you do increase the chance of it elsewhere.

So as the last poster said if it aint broke............