Before You Do Something Permanent, Know About Growth Plates

Before you do something that could impact your puppy’s growth pattern (like an early spay/neuter, or physical activity that’s too vigorous),  you should know when the growth plates close on an average puppy.

Growth plates, also known as the epiphyseal plates or physis, are “zones” of cartilage that exist at the end of bones in both canine and humans as each grows older. They contain rapidly dividing cells that allow bones to become longer until the end of puberty in both humans and canines.  Growth plates gradually thin as hormonal changes approaching puberty signal the growth plates to close, and in most puppies, this is around the age of approximately 18 months old. At that point, the plates “close” because they’ve contributed all they can to the growth of the bones. The growth plate becomes a stable, inactive, part of the bone, but before then, the plates are soft and vulnerable to injury. An injury to the growth plate might not heal properly, nor heal in time for a puppy to grow up straight and strong. Such an injury can result in a misshapen or shortened limb, and that in turn can create an incorrect angle to a joint which can make the puppy more prone to even more injuries when he grows up.

But what about neutering a dog? How that that impact a growth plate?

Part of the responsibility of sex hormones is to regulate growth. When the sex hormones are removed,  growth hormones are missing important regulatory input and the bones continue to grow longer than they ought to.  Growth plates lay down bone as a puppy develops and, as it builds bone, the bone becomes longer and the puppy gets larger and taller. Once maturity is reached, this growth plate turns into bone and the puppy’s full height is reached. Most breeders can spot the difference between an intact dog and a dog neutered too young, and studies have proved it to be true (Salmeri et al, JAVMA 1991).

We have the kind permission of Deb Gross to share this fabulous chart,  but we ask that you include the following links if you’re going to share it. Click here to see a larger size.

Chart by Deb Gross of Wizard of Paws
Facebook page: https://www.facebook.com/Wizard-of-Paws-95319629966/timeline/
http://www.wizardofpaws.net/

 

 

21 thoughts on “Before You Do Something Permanent, Know About Growth Plates”

  1. It was concluded that with respect to skeletal, physical, and behavioral development, the effect of neutering pups at 7 weeks old was similar to that of neutering pups at 7 months old. – A direct quote from Salmeri : so the report does not conclude that which the author of this post professes it to.

    • An interesting comment, Rob. We were able to find what we think is the source of your quote from Dr. Salmeri (https://www.ncbi.nlm.nih.gov/pubmed/2045340) and noted that the same abstract mentioned a delay in growth plate closures in early neuters as compared to dogs who were neutered at an older age which may have resulted in longer bones. This hints at a connection to hip dyplasia.

      In a study of early neuters in Golden Retrievers, early-neutered males had double the occurrence of Hip Dysplasia compared with intact males (Torres de la Riva G, Hart BL, Farver TB, Oberbauer AM, Messam LLM, et al.

      Van Hagen et al (Am J Vet Res, Feb 2005), found that of dogs in their study diagnosed with hip dysplasia, those that were neutered six months prior to the diagnosis were nearly twice as likely to develop hip dysplasia, and in a study by Dannuccia et al (Calcif Tissue Int, 1986), they found that removing the ovaries of Beagles caused increased remodeling of the pelvic bone, which also suggests an increased risk of hip dysplasia with spaying.

      Chris Zinc DVM PhD DACVP said, “…if the femur has achieved its genetically determined normal length at eight months when a dog gets spayed or neutered, but the tibia, which normally stops growing at 12 to 14 months of age continues to grow, then an abnormal angle may develop at the stifle. In addition, with the extra growth, the lower leg below the stifle likely becomes heavier (because it is longer), and may cause increased stresses on the cranial cruciate ligament,” so now we have a connection to cruciate tears. Furthermore, Martin et al, Bone 1987 suspected that sterilization caused a loss of bone mass, and coupled with the fact that neutered females are twice as likely to become obese, the combination can lead to an increased risk of cranial cruciate ligament tear and hip dysplasia. Spayed/neutered dogs are also three times more likely to suffer from patellar luxation (Vidoni et al, Wien Tierartztl Mschr 2005). One has to suspect, then, the possibility that the increase in bone length that results from early-age neutering results in changes in joint conformation, which can lead to hip dysplasia, and other maladies.

      Early spays also hint at a connection to disease. In a study of early neuters in Golden Retrievers, almost 10 percent of early-neutered males were diagnosed with Lymphosarcoma which is three times more than intact males.

      A February 2014 study completed on over 2500 Vizsla dogs found that removing a quarter of the dog’s endocrine system might not be in the dog’s best interest since early spayed females had significantly higher rates of hemangiosarcoma (nine times higher) than intact females. Spayed/neutered dogs were 3.5% more likely to get mast cell cancer, and 4.3 times more likely to suffer lymphoma. The Vizsla study found that the younger the dogs were when spayed/neutered, the younger they were when diagnosed with cancer. (M. Christine Zink, DVM, PhD et al., Evaluation of the risk and age of onset of cancer and behavioral disorders in neutered Vizslas (JAVMA, Vol 244, No. 3, February 1, 2014). We presume that the Dr. Zink mentioned above is the same Dr. Zink who commented on femur length earlier in our comment.

      A Gerald P. Murphy Cancer Foundation study in 2009 found a correlation between the age at which female Rottweilers are spayed and their lifespan. The study compared female Rotties who lived to be 13 or older with a group who lived the expected lifespan of about 9 years. Dr. David J. Waters, a professor in the Department of Veterinary Clinical Sciences at Purdue University said, “”Like women, female dogs in our study had a distinct survival advantage over males. But taking away ovaries during the first [four] years of life completely erased the female survival advantage. We found that female Rottweilers that kept their ovaries for at least [six] years were [four] times more likely to reach exceptional longevity compared to females who had the shortest lifetime ovary exposure.”

      We actually had a chance to attend one of Dr. Waters’ seminars in which he discussed his “Old Gray Muzzle” tour of Rottweilers, and he offered compelling evidence of why neutering isn’t necessarily beneficial to a dog, let alone early neutering.

      This is a lengthy response to your comment which is valid, and we appreciate that you wrote it. However, given the data, early spays and neuters still sound risky.

    • I would never s/n a 7 month old. You need to wait until dog dog is mature. Why do people feel that removing parts of a dogs have no consequences on proper growth?

    • You are too vague.
      The point is that 7 weeks AND 7 months are BOTH far too soon for neutering. I doubt that the smallest breeds are “safe”to neuter before 10 months old. The “working size” breeds (Australian Kelpies, Border Collies. German Shepherd Dogs, Labrador Retrievers, etc) should not be neutered before 18-to-24 months old, and the giant breeds not before 36 months old.

  2. Agreed. I have 5 dogs, one of which was neutered at five months, the rest at age 2 or older. The young neutered dog is several inches taller than the others and an “off” gait. Additionally, he stands with his rump slightly lowered and rear legs bent slightly, almost like what you would see in early stages of Degenerative Myelopathy (DM). Gratefully, his genetics do not suggest DM. He was my first puppy and I made the mistake of believing I was doing the right thing by neutering before puberty. But I was very, very wrong. I understand why dogs are routinely altered at 6-8 weeks in shelters, but hopefully one day, we can stop that madness as well.

    • Thanks for the comment, Jake, feedback based on personal experience is helpful, and indeed, powerful when combined with similar experiences. We do the best we can with what we know at the time, and we’re guessing that the medical thinking at the time that you neutered your dog believed in early neuters. You wouldn’t be the first, and you’re not to blame yourself.

  3. This is definitely a subject I have gone back and forth on. My first female Doberman was not spayed until she was 7 years old. She was huge, way oversized in both height and weight for a female and lived to be 14. She died with hemangiosarcoma and mammary cancer. My next 2 were males, one neutered at 10 months and the other at a year. The one neutered at ten months was very tall but comparable to his sire. He had some health issues but were more attributed to bad breeding and skin issues due to him being blue. He lived to be 10, dying of natural causes. The other male that was neutered at a year is still alive at 10, he’s a good large sized male but has liposarcoma. I know 3 people with his male littermates, one intact and the others neutered at different ages, and they also have liposarcoma so I attribute that to genetics. Another female I had, rescue after being bred all her life and given up bc she could no longer breed at 8 due to osteosarcoma, she was spayed via the shelter at 8 and I had her for 9 months before she passed. I currently have a 4 year old female Doberman that was spayed at 7 months, she is not oversized and is of European lineage. Average height and 74 pounds. She is the picture of health at this point. Those are just my dobermans. I’ve had, and have, other breeds all spayed/neutered at various ages due to rescue but in my personal experience the ones I’ve had most health issues with are the ones that were altered later. It’s an interesting subject.

  4. What about toy sized dogs? Don’t they mature faster? My 8 mo old has all his adult teeth and has definitely hit maturity. Is there a difference due to size. All of the dogs mentioned in this article are bigger dogs

    • Susan, you ask a great question that would make a good post once we research it. Giant and large breeds tend to have different issues related to rapid growth, but as you said, toy breeds often mature more quickly. We’ll look into this!

      • Please do I would love to read your results we are always ask this question what is the best time to spay and neuter a toy breed and I would love to read some medical evidence and facts on why

        • We’re not sure what you’re asking us to do, Cassandra, but if it’s any help, we did a Google search on “early neutering of toy breeds” and came up with pages of results that may help you form a consensus of how to answer the question of when to s/n a toy dog – and why.

    • According to the American College of Veterinary Surgeons, Jackie, the risk of a dog developing a mammary tumor is 0.5% if spayed before their first heat (approximately 6 months of age), 8% after their first heat, and 26% after their second heat.

      From another study:The incidence of canine mammary tumors found tumors in approximately 0.05% of females that were spayed before their first heat cycle. This figure increased to 8% or 26% when the animals were spayed after their first or second heat, respectively. However, if the animals were spayed later, the risk of developing malignant tumors (MN) was the same as for an intact bitch.

      A paper from Penn State: The risk for developing mammary gland tumors is closely associated with exposure to the female sex
      hormones estrogen and progesterone in the early years of development.

      You may find this interesting: https://www.sciencedaily.com/releases/2019/11/191101183437.htm

  5. We are considering the purchase of a purebred Beagle puppy (13-inch) that is 8 weeks old. He underwent hernia surgery yesterday and was neutered at the same time. I understand the breeder’s rationale for doing so but are there early-neuter health risks that we should be aware of for this breed? We just want a pet and hadn’t planned to show or (obviously) breed him.

    • Deb, you ask a loaded question of us when we aren’t health professionals – and not even close. The deed has been done, and from this point forward, be mindful of the activities you ask of your Beagle. He will undoubtedly be a wonderful companion throughout your life, but it were up to us, we’d be gentle with those joints, and as he enters his middle age, routine physicals and blood tests would be a good idea.

      • Thanks so much. We would have waited until he was 6-8 months old but it wasn’t our choice. We are retired with no kids, so maybe this dog would fit better into our lifestyle better than with a more active family. It’s fine with me if he rarely leaves my lap.

  6. I have a 12 month old Golden Retierver who has cyrpto testicles (both have not dropped). We will have to neuter him. I want to balance the correct age to do this. Is 12 months to soon or should we wait until 18 months.

    • Steve, we’re not veterinarians, not even close, and would always encourage you to discuss this with your own vet. That said, our own personal “take” on the subject is to wait until he’s a bit older.

  7. Hi. Read through all of your discussions. My female French bulldog is due to be spayed tomorrow. She is just 9 months. I’m inclined to cancel and let her have at least her first heat….or should I go ahead and spay her tomorrow? Please help make this decision for me.

    • Rene, we’re not in a position to help you make a big decision like this, we’re neither veterinarians nor health care professionals. For what it’s worth, however, once the surgery is done, there is no going back. If you wait a little bit longer, the surgery can always be performed when she’s had her first cycle. Normally, we’d advise you to consult your vet regarding what’s best for your little Frenchie, but these days, many vets have bought into spaying everything in sight, and the sooner the better. If you’ve read through the discussions, you’ve noted that not everyone agrees with this stance. We hope this help you make your decision, let us know what you end up doing.

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