We recently added a Great Pyrenees puppy to our family December of 2013 and upon his first Vet visit the vet urged us to neuter him at 12 weeks AND have his double dews removed. Great Pyrenees are the only breed supposed to have them. My husband and I felt off about this decision as the last vet I had urged us not to alter a large breed before 6 months of age as it can cause major issues in bone development. I decided to do a little research on my OWN. I found that not only should I NOT alter him at 12 weeks but I found out that his breed specifically should not be altered before 8 months of age due to a unique molar they have that doesn't come in until then and they need all of their hormones to push them out as well as it can negatively impact his bone density as he grows. Without them it can cause some serious jaw issues according to a reputable Pyr Breeder. I also found out that you should NOT have a Great Pyrs double dews removed as it can cripple them and cause early onset of arthritis and tendinitis. I decided to look for a new vet. My current Vet stays up to date on the studies that are being conducted on the pros and cons of neutering large breeds too early. He has suggested that anything classified as a large breed should not be altered before 6 months old due to the chances of something being caused by it. He is not set one way or the other but as he told me, "There are no bad things claimed about waiting until 6 months that are caused but there are many bad things claimed that are caused by it". To me, I would rather be safe than sorry and wait a little longer and if you are observant and responsible enough an unwanted litter will not happen in that time. WHY are we being urged to alter our beloved pets before they are fully mature when it has the potential to cause severe health issues down the line or issues that are unknown to us at this time.
Case and Stella are happy and healthy puppies right now and we made the right choice for THEM and excluded anyone else's thoughts and opinions on the matter due to the fact WE have the emotional attachment to them not the next person. They are our responsibility and it is our duty to do what we feel is right for them at that time and with the information that is at hand.
All I can say is trust your gut not always the professionals! Just because they say it is right does not mean it is right for your pet.