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
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.