Countering the Effects of Spay


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 uterus and the hormones they produce.

For many 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, 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.

If your dog does not experience orthopedic 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 a 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

This research is important for two reasons: first it exemplifies the complexities of the thyroadrenal interactions. Second, it proves the point that recovery from the endocrine disruption of neutering 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). However, the overriding reason for hormone replacement is to counter the more systemic damage done to your dog’s endocrine system by ovariohysterectomy.HAHD_hormone_imbalance For practical purposes, 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 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 younger age – often 4-5 years of 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 ligament is torn, the orthopedic surgeon will not insist the second one will tear. 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 and adrenal hormones after it appears she has recovered from the surgery. This is a pivotal point because outward appearance would indicate your dog has healed from her surgery. However, the damage spay inflicted upon your dog’s endocrine system likely will not allow normal immune or metabolic response to the stress of a 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 normal level of sex steroids your dog requires. Lack of sex steroids may cause neurotransmitters required for proper brain function to be unavailable or overproduced. The thyroid may be a problem as well, but it may resolve after corrective action to improve the other conditions 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 making 63 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 review 104 :

“…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.”

If there is 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 some evidence that SAMe behaves similarly in dogs’ brains, and may mimic the activity of progesterone in the dog brain. SAMe is believed to affect mood 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. It is also reported that SAMe reduces the amount of adrenalin in the brain, which helps to offset the increase of adrenalin in the brain under stressful conditions. There are SAMe supplements available that have been formulated specifically for dogs. 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 our vet and was beneficial to his liver, somewhat helpful for his joints, and extremely helpful for his fear and anxiety.

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 2005 34 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 making 63 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.