I have an older very good Orthopedic Veterinarian, and I asked him if he had seen a greater incidence of problems since the early spay/neuter began.  His answer was a resounding yes.  He said that rarely had they seen hip dysplasia and joint issues like luxating patella in the smaller dogs.  Since early spay/neuter, it has become more and more common.  He explained to me that just as with humans, sex hormones are responsible for a lot more than reproduction and associated behaviors. One major responsibility is regulating growth. When you surgically alter a dog and remove those hormones, you affect its growth. Bones continue to grow longer than they should. Because different bones in the body stop growing at different times, some bones would wind up longer than they should be. And that causes problems.

                                            Take the knee joint for example, above the knee is the femur bone, and below                                                  is the tibia and fibula.  The femur grows to normal length in around 8 months,                                                but the tibia typically doesn’t stop growing until 12 to 14 months.  According to                                              Chris Zink, well-known veterinarian and specialist in canine sports                                                                     rehabilitation and medicine, if the dog is spayed or neutered before the tibia                                                  has finished its growth, it will continue to grow longer than it should, altering t                                              the normal angle of the knee. It also puts pressure on the hips and spine. And                                                because the tibia grows longer, it’s also heavier, putting additional stress on                                                    the cranial cruciate ligament. Research supports the fact that dogs who were                                                  spayed/neutered early were twice as likely to tear their CCL, and 3 times more                                                likely to have a luxating patella.

One thing is clear – much of the spay/neuter information that is available to the public is unbalanced and contains claims that are exaggerated or unsupported by evidence.  Rather than helping to educate pet owners, much of it has contributed to common misunderstandings about the health risks and benefits associated with spay/neuter in dogs.  What is now factual, is that the traditional spay/neuter age of six months as well as the modern practice of pediatric spay/neuter appear to predispose dogs to health risks that could otherwise be avoided by waiting until the dog is physically mature.

What are the Facts:

1. Spaying and neutering too early will deprive your dog of the sex hormones necessary for its maturation. These hormones are responsible for skeletal growth. If the procedure occurs too early, it may take much longer for your dog's growth plates to close.

2. There is a significant increase in the risk of osteosarcoma (bone cancer) in dogs neutered before 1 year of age and other cancers. As with spayed females, this is common cancer that occurs in larger breeds with a poor prognosis. There is an increase in the risk of cardiac hemangiosarcoma by a factor of 1.6m and a tripled risk of hypothyroidism.

3. Early spay/neuter causes loss of bone mass.

4. Dogs who are spayed/neutered before 6 months have a 70% increased risk of developing hip dysplasia.

5. Dogs who are spayed/neutered too early have an increased chance of developing undesirable behavioral issues such as phobias, fear aggression, and reactivity.

6. Early spay/neuter triples the risk of developing hypothyroidism and becoming obese.

Interestingly, when to spay does appear to be very breed-specific.  So if you are reading this article and you do NOT have a miniature schnauzer you may want to consult this study which was recently done: The study “Assisting Decision-Making on Age of Neutering for 35 Breeds of Dogs: Associated Joint Disorders, Cancers, and Urinary Incontinence” (Hart BL, Hart LA, Thigpen AP, Willits NH) was released in July 2020 – it covers 35 different breeds – and a separate scientific paper for mixed breeds. The study followed a total of 15,414 dogs over 15 years of recording.  You can click on this link to read the entire article: Click Here!

We’ve covered the reasons not to do an early spay (7 months or earlier).  However, there is another consideration which is the risk of surgery.  1 in 2000 dogs will die just from the anesthesia.  While that is a small percentage, I have had people lose females and males to anesthesia.  Because I raise small dogs, it’s important to know that Toy breeds are at increased risk for anesthetic complications because they are more prone to hypothermia, may be more difficult to intubate and monitor, and are more easily overdosed, according to the AAHA. Giant breeds also can be at increased risk since the dosage amounts required are large.

Spaying a female is major surgery.  It’s the exact same surgery as a human receiving a hysterectomy.  The total time under anesthesia is 30-90 minutes. Neutering a male is a much less complicated surgery and takes from 5-20 minutes, which is why it’s often referred to as a “Snip-Snip” procedure.