If your dog has already been spayed, there are some things you can do to help her live the healthiest and happiest life possible. The best chance you have to keep your dog healthy is to assess and confirm the point in time that her adrenal glands are no longer able to compensate for the loss of her ovaries and the hormones they produce.
For some dogs, after they are spayed, they appear to be okay, i.e., no major health problems, no behavioral issues. If they live in a happy environment with adequate attention and exercise (we will discuss the significance of these in more detail later), they may reach 7 or 8 years of age before you notice any problems. If that’s the case, thank your lucky stars. Your dog was spayed after her bony growth plates had closed. The bony plates generally close between 4 and 18 months of age, depending on the individual dog. If this is the case for your dog, she probably won’t be afflicted with the worst of the orthopedic problems we have detailed on this web site. However, no spayed dog is immune to the hormonal chaos spay creates – the difference is the timing.
There are a significant number of female dogs who experience behavioral changes after spay, and for some the changes are dramatic and immediate. At this point in time, most veterinarians are recommending obedience training and/or behavior modification and if these are not satisfactory, they might prescribe antidepressant medications. From our perspective, this approach is counterproductive or at best, merely ineffective. To correct a problem you must first accurately identify the underlying cause of the problem. The negative changes in your dog’s behavior are the product of structural and functional changes in their brain due to a lack of sex hormones. The ideal remedy is to balance their hormones and hopefully achieve the hormone levels of an intact dog (please see our sections entitled “Behavioral Effects of Spay” and “The Stress Response System” for a detailed explanation of this phenomenon and discussion of remedies). Balancing hormones offers the best opportunity to enhance physical health as well as restore the balance of neurochemicals (i.e. serotonin, norepinephrine, dopamine, etc.) in the brain. Balancing hormones is complicated and when behavior is still problematic after hormone balancing, we favor supplementation with SAMe and perhaps DHEA rather than antidepressants. Antidepressants have significant side effects and are not designed to address excess norepinephrine generally found in the brain of symptomatic, spayed dogs.
If your dog does not experience orthopedic or behavioral problems, the first warning sign that her adrenal glands can no longer compensate for the sex hormones lost from spay may be incontinence. If your dog is suffering from some level of incontinence, the most likely culprit is a low level of estrogen. It is so common as to be described in the veterinary literature as “spay incontinence“. Some veterinarians may prescribe phenylpropanolamine (PPA), which can sometimes successfully resolve the symptoms, however there are risks with the use of this compound, and the underlying hormonal deficiency still persists. Estrogen replacement therapy is another option, but should not be undertaken without a hormone panel to confirm if estrogen and other hormones like progesterone and testosterone are also deficient. It is extremely important for females to include DHEA in the panel.
There is an opportunity to enhance the female dog’s ability to produce estrogen even after ovariohysterectomy. Dehydroepiandrosterone (DHEA) is a hormone that can be made into estrogen or testosterone and it is mainly secreted by the adrenal glands in females. The ovaries’ contribution to circulating DHEA appears to be limited, although in intact females it may partially compensate for an age-related decrease in adrenal hormonal secretion.101 Spayed females don’t have the ovaries to fall back on when the adrenal glands are overwhelmed by stress, the additional demands of hormone production due to spaying, and age-related decrease in secretion. If the hormone panel shows a deficiency in estrogen and DHEA, supplementation with DHEA103 could allow additional estrogen production in the brain or fatty tissue.102 Because the additional estrogen will be naturally produced within your dog’s body, you will have no concerns as to whether the estrogen will be synthetic, natural, or bioidentical, as is the case in traditional hormone replacement therapy. If the DHEA supplement leads to additional estrogen production, the spay incontinence will generally resolve. DHEA is inexpensive and can be purchased over the counter at local pharmacies or online pharmacies. There are no exact dosing recommendations we can find, however, studies do tend to give a range of dosing that appears to be safe – 10 to 25 mg. orally, each morning.
Another set of symptoms that are an indicator of adrenal insufficiency may be general lethargy and perhaps some confusion.55 Don’t assume it’s inevitable because she is getting older. Have your dog’s thyroid gland hormones and adrenal/sex hormones tested. If the thyroid gland hormones are low, most veterinarians will be very comfortable prescribing thyroid hormone supplements. However, if the adrenal gland function (and sex hormone level including DHEA) is also not normal, it may not be in your dog’s best interest to supplement the thyroid hormone alone. In case studies where adrenal hormones are also abnormal, adrenal hormone replacement therapy returned the thyroid levels to normal without the need for thyroid hormone replacement.105
The aforementioned research is important for two reasons:
- It exemplifies the complexities of the thyroadrenal interactions.
- It proves the point that recovery from the endocrine disruption of spay is not straightforward; endocrine (hormonal) interactions within your dog are a complex web of inter-related feedback mechanisms.
As in the example above, simply adding in a hormone which is low may not solve the problem, but actually make it worse. On the other hand, your dog’s incontinence and/or behavior problem(s) may be a barometer as to the necessity for hormone replacement. And, replacement of a single hormone may resolve the observed incontinence and/or behavior problem(s).
Another significant reason for hormone replacement is to counter the more systemic damage done to your dog’s endocrine system by spay. In female dogs we find the presence of estrogen/progesterone in appropriate amounts has a statistically significant protective function in preventing three serious, deadly cancers found in dogs. These cancers would be hemangiosarcoma, lymphosarcoma (lymphoma) and mast cell tumor (see our cancer page for a more lengthy explanation). The actual mechanism whereby estrogen and possibly progesterone exert their protective influence is not understood, but the data is compelling and cannot be ignored.
With respect to cancer, the argument is often made that spay minimizes the risk of mammary cancer. A recent meta-analysis of the evidence has shown the research supporting this oft-repeated argument is seriously flawed and should not be relied upon. We do suggest that female dog guardians, regardless of whether your dog is spayed or not, perform manual exams of their dogs chest area routinely, and ask that their vet evaluate their dog for mammary cancer at each vet visit. As in humans, routine exams can detect mammary (breast) cancer at an early stage where it is more successfully treated.
With respect to hormone replacement therapy, we find hormone “re-balancing” may be the better term to use. Some hormones will be in excess, while others may be deficient. Identifying the hormones required, and their corresponding quantities, is difficult to ascertain with any degree of certainty. The goal is to restore balance to your dog’s endocrine system to enhance her ability to respond to stress and thereby prevent the development of cancer, Cushings, diabetes, and other endocrine related diseases. Please refer to the Diseases – Overview page and “The Stress Response System” page on this website for a more in-depth explanation of the overarching effects of spay/neuter on your dog’s ability to respond to stress.
If your dog was spayed before her growth plates closed, the first health related problems you see may be orthopedic, and they may occur at a young age. If your dog struggles to sit and get up from a sitting position and is moving poorly in general (see Billy’s videos on his timeline), your dog may have torn the cranial cruciate ligament in her knee(s). If just one knee’s ligament is torn, the orthopedic surgeon most likely will not insist the other knee’s ligament will tear as well. However, based upon our current knowledge as to the cause, it’s pretty clear you can expect the second knee to have the identical problem. Similarly, in the case of elbow and hip dysplasia, you can expect the dysplasia to be bilateral.
If you proceed with surgery for any of the aforementioned orthopedic issues, you should test your dog’s thyroid, sex and adrenal hormones after it appears she has fully recovered from the surgery (this will vary for every dog). You want to be sure you have allowed adequate time for the adrenal gland to recover from the stress of surgery before testing. You will be the best judge as to whether your dog has recovered to the level of strength and activity that she possessed prior to the injury. This is a pivotal point because outward appearance would indicate your dog has healed from her surgery. However, the initial damage spay inflicted upon your dog’s brain and endocrine system likely will not allow normal immune or metabolic response to the stress of a subsequent surgery. The stress of a surgery may stimulate your dog’s adrenal glands to produce cortisol, so much cortisol that the adrenal gland is no longer able to produce the level of sex hormones your dog requires. Lack of sex hormones will again cause functional and structural changes in your dog’s brain as well as dysregulation of the endocrine system. This will predispose your dog to metabolic disease (e.g. diabetes) as well as immune-mediated disease (e.g. cancer). The thyroid may be a problem as well, but it may resolve after hormone re-balancing as described above.
There are simple blood tests to determine levels of estradiol, testosterone, thyroid, progesterone, and DHEA. We do want people to get tangible evidence of hormonal imbalance before making significant changes through supplementation. You should also attempt to employ shared decision making63 to make some improvements to your dog’s hormonal balance that you and your veterinarian can feel comfortable with. For female dogs who exhibit signs of agitation (sometimes to the point of panic), generalized anxiety, fear of new people, dogs or new situations, they may be deficient in estrogen as well as progesterone. It came as a surprise to the authors of this systematic review104 :
“…that responses to estradiol are present in brain regions that are not directly associated with reproductive success but are important for learning, memory, emotional responding, mood, and sensorimotor control…there is substantial evidence for the therapeutic benefits of estrogens in the brain.”
It is this fundamental misconception on the part of the veterinary community (that sex hormones are only relevant to reproduction) which initially allowed spay/neuter to be institutionalized as the preferred means of canine population control. Spay/neuter persists today because veterinary professionals continue to ignore the research that recognizes the breadth of the influence sex hormones have over entire body systems independent of reproduction.
If testing reveals a deficiency of DHEA, estradiol and/or progesterone, you should be able to supplement under the supervision of your veterinarian.
Another option may be a supplement humans often take, SAMe, for mood regulation. There is evidence that SAMe behaves similarly in dogs’ brains, and may mimic the activity of progesterone in the dog brain. The research best supports the concept that SAMe helps neutralize norepinephrine in the brain. Norepinephrine is found in excess in the brains of dogs unable to appropriately respond to stress. An alternate theory is that SAMe acts by helping to increase the availability of neurotransmitters, such as serotonin and dopamine (which are attributed to feelings of emotional well-being), as well as increasing the number of neurotransmitter receptors. There are SAMe supplements available that have been formulated specifically for dogs, and the reported side effects are negligible. Scientific research also supports SAMe’s ability to promote liver health and joint comfort – key components to physical health and wellbeing.
Sometimes when a dog has elevated liver enzymes, a combination of SAMe and silybin (milk thistle)17 is recommended. These are available as generics formulated for dogs or in combination as Denamarin. Denamarin does not require a prescription and was recommended for Billy by his vet and was beneficial to his liver, somewhat helpful for his joints, and extremely helpful for his fear and anxiety.
Earlier on this page, we mentioned the importance of adequate attention and exercise for your dog, especially if she is spayed. There is scientific evidence to support these “common sense” suggestions. There are neurochemicals found in the brains of dogs and humans which promote feelings of happiness or bliss. In light of all the negative effects of spay on the brain, an activity that enhances brain chemistry may make a significant difference in your dog’s quality of life.
As is the case with humans who run frequently, researchers have discovered that dogs also experience a “runner’s high” The “high” comes from the release of endocannabinoids (eCBs) during moderate to high intensity exercise. Walking, such as on a leash, is not sufficient intensity of exercise to stimulate release of eCBs.166 Our dog Billy was run close to 6 miles daily at the beach near our home, and we found it was extremely helpful in alleviating his anxiety. Not everyone can run far enough or fast enough to give their dog adequate exercise to provoke the release of eCBs. But certainly most anyone can play fetch with their dog. Some dog guardians comment that their dog seems obsessed with their ball/frisbee. Perhaps their dog is simply addicted to the “high” running after the ball/frisbee provides them.
We also suggest it is important to give your dog adequate attention. Certain neurochemicals known to provide psychological benefits are generated in humans when they have positive interactions with other species. Consistent with the canine-human connection, in 2003 a study was conducted to see if the same neurochemicals and psychological benefits would be present in dogs. The study’s results confirmed that concentrations of beta-endorphin, oxytocin, prolactin, beta-phenylethylamine and dopamine increased in both humans and dogs through their positive interaction.167 In 2010, at the 12th International Conference of Human-Animal Interactions, scientists presented their findings confirming that friendly human-dog interaction releases oxytocin in both human and dog.
The most concrete recommendation we can offer that can protect your dog from the adverse effects of spay/neuter is with respect to vaccinations. Because spay/neuter has an adverse effect on the immune system, guardians of spayed/neutered dogs must be cautious with respect to vaccinations. A study was conducted in 200534 to analyze adverse events diagnosed within three days of vaccine administration in dogs. The vaccine-associated adverse events included nonspecific vaccine reaction, and allergic reactions varying in severity from a rash or hives all the way to anaphylaxis (which can block breathing and be fatal). The study found danger of an adverse reaction goes up substantially when a dog is spayed or neutered, and the less a dog weighs, the more likely they are to experience an adverse reaction. Further, the risk increases substantially with each additional vaccination given at one time.
Additionally, in 2011 the American Animal Hospital Association (AAHA) canine vaccination task force updated their vaccination guidelines. Rabies vaccinations remain effective for a period of 1 to 3 years, depending upon your previous method of vaccination. However, the task force changed the previous recommendation for distemper, parvovirus and adenovirus from once a year to a frequency of once every 3 years. The task force also acknowledged in the updated guidelines that immunity lasts at least 5 years for distemper and parvovirus, and at least 7 years for adenovirus. In light of the greater risk of adverse reaction in spayed dogs, we do not see the wisdom of vaccinating more often than is absolutely necessary. Therefore, we suggest it may be prudent to consider a vaccination frequency of once every 5 years for distemper or parvovirus, and once every 7 years for adenovirus.
To be clear, we are not advocating the avoidance of vaccinations. We see this as an opportunity for shared decision making63 with your veterinarian to provide your dog with vaccinations on a schedule that is best for your dog. Additionally, best practice would be just one vaccination of any type on any given day, with a reasonable period of time between vaccinations. This precautionary approach becomes even more important when your dog is small.