my newfoundland dog is nearly four years old and weighs fourteen stone. what should he weigh. he has been castrated

Although many breed standards state a weight for a dog or bitch it is really better to assess the individual dog since even dogs of the same breed can have different builds and be of differing heights etc.You should be able to feel his ribs reasonably easily but he should also have a slight covering of body fat....ie he should not be a bag of bones.
Breed standard states dogs should be 26 inches tall and weigh 141-152 lbs which is 10-11 stone approx.
If your dog is overweight it can cause serious health problems and shorten his life span.IMO allowing a dog to become seriously overweight is as cruel as allowing it to be underweight
Archer

The breed standard asks for males to average 29 inches bitches should average 26 inches, your dog is definately overweight, i had a huge male and his weight was 11.5 stone. 
Please put him on a diet and give him more exersise - you'll both feel better for it :-)

Sharon

apologies Sharon....miss read the breed standard...its 26 inches for bitches.
Archer

BTW _ Castration shouldn't enter into it, a castrated dog should weigh the same as an uncastrated dog of the same breed ;)