Have you ever wondered why we call it “fixing” when we spay or neuter a dog or cat? If you were raised on a farm you might know the answer to that question. Males who have their gonads can be problematic, right? Remove those and the animal is “fixed.” This very general rule might make sense in the mind of a farmer with a male donkey or horse who is trying to jump on everything. However, when it comes to our companion animals, there’s a growing body of evidence proving that we’re not “fixing” much when we neuter and spay them, especially before maturity. In fact, the opposite holds true for the vast majority of health issues, including behavior! If that is the case, then why do we continue to do it? To answer that question, let us look at some history!
About a hundred years ago, dogs and cats were becoming a lot more popular as household pets, but there wasn’t a humane and reliable way to control the pet population, and the number of unwanted animals exploded. Prior to the 1970s, the few shelters that did exist were overrun by strays. It was around that time that the first low cost spay/neuter clinics started opening in North America. This led to discussions about the benefits of spaying and neutering and advocating for the procedure as an animal welfare issue. Several decades of aggressive campaigning (thank you Bob Barker) entrenched spay and neuter in the public mindset as being not only for the better health of the animal but as a way to reduce the number of unwanted dogs and cats, and shelters required sterilization for all animals prior to adoption.
The thing is, this practice continues. It is heart wrenching to know that puppies and kittens are today being spayed and neutered when they’re just a few weeks old. How can this not be affecting their development and long term health?
What Happens When We Spay Neuter Young Animals?
The concept of removing the reproductive organs before maturity (around 6 months of age or before a female’s first heat) to control the pet population, and possibly make dogs and cats more manageable, did not take into consideration the negative physiological consequences. The most obvious physical affect is the influence of hormones on the growth plates. In a developing puppy or kitten, major growth happens between 3 and 6 months. Most animals achieve 90% of their adult size by 9 months of age. Most growth plates close between 4 and 12 months, depending on the anatomical structure, size and breed. In large and giant breeds, the plates might not close until 15-18 months of age. The growth plates of the long bones are the last to close. The average size dog (25-30kg/55-65lbs) will continue to see growth of those bones until 11-12 months of age. In an animal who is neutered or spayed before maturity, the growth plates, especially of those long bones, take longer to close in the absence of the sex hormones. This often results in an animal who is taller, with abnormal musculoskeletal structure.
But that’s not all… early spay or neuter can also lead to:
- osteosarcoma (bone cancer)
- cruciate ligament tears and ruptures
- hip dysplasia
- elbow dysplasia
- physeal (long bone) fractures in male cats
- hemangiosarcoma (cancer of the heart or spleen)
- lymphosarcoma (cancer of lymphatic glands and tissue)
- prostate cancer
- urinary tract cancer
- urinary tract blockage in male cats
- mast cell tumors
- cushing’s disease
- atypical cushing’s
- diabetes
- incontinence in female dogs
- allergies
- alopecia (hair loss)
- obesity
- negative vaccine reactions
- excessive fear of people or dogs
- fear of noises
- separation anxiety
- touch sensitivity
- cognitive impairment
- aggression
Why Spay Early?
One of the most common reasons cited for spaying a female before her first heat is to reduce the risk of mammary tumours. In 2012, a meta-analysis of the medical literature was undertaken and published in the Journal of Small Animal Practice. Its authors discovered that many frequently cited references were over 40 years old. They concluded, due to the limited evidence available and risk of bias in the studies, that the evidence that spaying reduces the risk of mammary tumours and that the age at spay has an effect, were weak and not sound basis for firm recommendations. They recommended further research and association between mammary tumours and spaying should focus on recording age, breed, previous exposure to synthetic ovarian steroids, age at time of spay and how many years she had been a spayed female before tumours developed.
Another study led by a team of researchers at the University of Pennsylvania State School of Veterinary Medicine, published in October 2019, looked at the role estrogen plays in development of mammary tumors in dogs. 159 shelter dogs with mammary cancer were studied, 29 intact, the rest spayed. Here is an excerpt from an article in Science Daily:
“Despite estrogen’s link with an increased risk of developing mammary tumors, the researchers found that higher serum estrogen levels also seemed to help dogs avoid some of the riskiest aspects of their disease. Unexpectedly, when dogs were spayed at the same time their tumors were removed, those with estrogen receptor-positive tumors that had higher serum estrogen took longer to develop metastatic disease and survived longer than dogs with lower estrogen levels, confirming that these tumors depended on estrogen for progression… ‘It drives the cancer, but it also seems to control or modulate it, reining it in…‘
The protective role of estrogen was also surprisingly pronounced in dogs with estrogen-receptor negative mammary tumors. In these higher-risk cancers, high serum estrogen was associated with delayed or absent metastasis. Complementing these findings and supporting a potential broader, tumor receptor-independent anti-cancer effect driven by estrogen, dogs with low serum estrogen had a significantly increased risk for developing other non-mammary aggressive fatal tumors, such as hemangiosarcoma, during their follow-up after mammary tumor surgery.”
A common justification for early neutering of bitches is that it protects against mammary neoplasia. However, many frequently cited references are over 40 years old!
The reproductive organs are not alone in producing sex hormones. The endocrine glands also produce small amounts. When the sex organs are removed, the animal’s body will attempt to compensate for the loss. It does this by enlisting the endocrine system, namely the adrenal glands, to work harder to stimulate production. It makes sense that we would see issues plaguing this body system from the added relentless stress.
Current scientific study has established that sex hormones profoundly affect the body. The list of diseases and disorders that can be linked to the loss of sex hormones is long (as you may have noticed above), and there is so much research to back that long list up…
Reading the Research
Dogs who are spayed and neutered can be more aggressive, especially to their own family. Two large scale studies involving nearly 16,000 dogs have established this. One was conducted in 2006 by the School of Veterinary Medicine at the University of Pennsylvania, the other a masters’ thesis at Hunter College in New York submitted in 2010.
Another study, published in 2009, established a link between the age at which female Rottweilers were spayed and how long they lived. The normal life span of a female Rotti is considered to be about 9 years. However, some are living to 13 years or more. The study showed that females live longer than males, but spaying before age 5 removed that longevity benefit. Females who kept their ovaries until at least 6 years of age were 4 times more likely to be long-lived compared to those who were spayed at a younger age.
The majority of studies being done involve dogs, but it would stand to reason that cats would be affected by early spay and neuter also. Certainly there need to be more comprehensive studies to assess the impact on our felines. It is suspected that loss of those hormones before maturity leads to increased risk of urinary blockage in male cats due to the ureter becoming hair thin following neuter. Cats are often neutered and spayed before sexual maturity because of the undesirable behavior displayed, especially by males. There was a small study in published in 2002 that found a link between early neuter in male cats and spontaneous physeal (long bone) fractures due to delayed physeal growth plate closure. Thus far however, it appears our canine companions are much more negatively affected by early spay and neuter than kitties.
**There are health issues that we know can be avoided completely by spaying and neutering. They are pyometra (infection of the uterus) in females and benign prostatic hypertrophy (enlarged prostate) in males.
What Can You Do?
Let us start by saying that each animal and each pet parent is an individual. The decision if and when to spay or neuter will depend on breed, personality, your lifestyle and the commitment you can make to training and responsibility. For responsible pet parents, where there is no risk of their sexually mature dog or cat either accidentally impregnating another or getting pregnant, the following would be recommended:
If you plan on sterilizing your puppy, wait as long as you can. For small breeds, wait until they’re at least a year old, medium sized dogs 1.5 years, large dogs 2-2.5 years and giant breeds at least 3 years. If and when you have the procedure done, seek out a veterinarian who will do for females either a tubal ligation or an ovary sparing spay where the uterus is removed but the ovaries are retained. For males, a vasectomy would be the preferred procedure.
If you have a kitten and you can do so responsibly, wait as long as you can. Male cats will start exhibiting those off-putting behaviors between 7-10 months of age. Males can become more aggressive and can also start urine spraying and marking. Females show clear signs of being in heat with dramatic vocalization and amorous behavior.
Remember – dogs and cats are very different. Female canines generally start their first heat between 7 and 12 months (lasting about 3 weeks) and then have, on average, a heat cycle every 6 months. Your female feline, once she goes into heat, can mate and produce offspring at any time, as she can ovulate spontaneously when there is male contact. If you have a male and female cat both intact living together you’ll need to get at least one of them spayed or neutered younger to avoid a litter and keep them separated from 4 months of age until one of them is “fixed.” A male cat has the potential of doing the deed at 5 months of age, possibly younger, and a female can potentially go into season between 5 and 6 months of age! Kitties who are looking for some action will most definitely try to escape out of the house to seek out a mate. I cannot stress enough the importance of being responsible so there is no way of ending up with an unwanted litter.
Too Late to Wait?
If you have an animal who was spayed or neutered either before maturity or after, you can rebalance their hormones by working with a holistic veterinarian or qualified practitioner to get their hormone levels tested and then incorporate natural sources of the hormones they have lost, or by using actual hormone replacement therapy. Start with the Healthy and Happy Dog website which is an invaluable resource: https://healthyandhappydog.com/
A very effective way to help rebalance the hormones is to give the homeopathic remedy in 30C potency, made from the organs they have lost: Canine Teste, Feline Teste, Canine Ovary or Feline Ovary, to help their body better compensate for the loss of those hormones, protect against the diseases and disorders for which they are at higher risk and bring them back into better balance physically and mentally. These remedies can also help those animals who are already suffering from loss of hormone related issues. For more information please contact me through my website: https://www.andrearing.ca/
I wanted to share what I feel is one of the silver linings to these stressful times we are living in. I have had so many people contact me, concerned that their dog or cat has not been able to go in for spay or neuter because veterinary clinics are only taking urgent or emergency cases and not performing routine surgeries. An animal that was 6 months old and due to have the procedure 3 months ago, is now 9 months old and may have to wait another few months! It’s a blessing in disguise that they have had to wait! It is an opportunity for education and awareness that many pet parents might not have otherwise come across and their animals will be healthier for it!
