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Lately, there has been more literature about sterilization options for dogs, and more owners are asking about alternatives to the commonly offered castration, ovariohysterectomy (OVH), or ovariectomy (OVE). The choice of sterilization option is very much dog- and family-dependent, and is not always straightforward. The goal of this article is to discuss the pros and cons of gonadectomy in dogs, as well as gonad-sparing surgical options (vasectomy and hysterectomy, or “ovary-sparing spay”).
There are many pros to sterilization in general, and specifically to gonadectomy for both male and female dogs. Pros of sterilization for male dogs (via any method) include population control, the ability for pets to go to daycare, and reduced municipal pet licensing fees. Pros of removing sex hormones (via castration) in male dogs include decreased risk of many prostatic concerns (e.g., benign hyperplasia, cysts, prostatitis, and abscesses), perianal adenomas, perineal hernias, testicular torsion, and testicular tumors. Note that dogs with cryptorchidism are more predisposed to the latter two conditions, and castration is always recommended for these dogs. Cons of removing sex hormones specifically in male dogs include a possible increased risk of prostate cancer, though this is still a very rare type of cancer.
Pros of sterilization for female dogs (via any method — removal of the uterus, ovaries, or both) include eliminating the risk of pyometra and dystocia, and it allows for population control. Pros of removing sex hormones (via OVE or OVH) in female dogs include reducing the risk of (to nearly eliminating) mammary cancer, pseudopregnancy, ovarian and uterine tumors, and vaginal hyperplasia and prolapse. Cons of removing sex hormones specifically in female dogs include higher risk of urethral sphincter mechanism incontinence or “spay incontinence.”
Until the recent years, cons of gonadectomy in dogs were not commonly discussed. However, recent literature is focusing on sterilization options and timing, and several concerns have come to light. Cons of removing sex hormones in male and female dogs include obesity, predisposition to cognitive decline, increased risk of orthopedic conditions (including hip dysplasia and cranial cruciate ligament rupture), and increased risk of oncologic conditions (by 2–4x in a study of golden retrievers and by 4x for osteosarcoma in a study of Rottweilers). The main cancers currently known to be more likely in gonadectomized dogs include hemangiosarcoma, lymphoma, osteosarcoma, mast cell tumors (MCT), and transitional cell carcinoma — cancers, other than low grade MCTs, that carry poor prognoses.
These cons to gonadectomy make it challenging to give an age at which gonadectomy is best, or if gonad-sparing sterilization may be a better option. When considering orthopedic problems, waiting until skeletal maturity for gonadectomy or gonad-sparing surgery (e.g., hysterectomy or vasectomy) is advisable to minimize those risks. For intact males, most of the conditions that affect them are relatively benign, treatable, and happen in older age. In intact females, the risk of mammary carcinoma makes choosing a surgery more difficult, as it is a potentially fatal condition. Thus, taking into account the breed and family concerns is largely how to decide which surgery is appropriate. For example, for a male golden retriever who has predispositions to orthopedic and oncologic conditions, and whose risks increase with gonadectomy, the choice may be vasectomy; however, the choice for a female without those predispositions may be gonadectomy. Importantly, the longer the duration of sex hormones, the more protective they have been found to be (meaning gonadectomy at later age may be helpful with regard to the previously discussed conditions). Early sterilization with gonad-sparing surgery, and with gonadectomy at a later age may be appealing to try to optimize the benefits of both options.
The pros and cons of gonadectomy with regard to behavior are not well established, other than that it eliminates sexually dimorphic behaviors. If an intact dog has behavioral concerns, a consult with a veterinary behaviorist is recommended prior to sterilization surgery to choose the best option for that dog.
A chart of the pros and cons to gonadectomy is below. Importantly, there is no universal “right” answer to which surgery and when is best for dogs overall. Instead, this is a topic that should be discussed with owners to help guide them toward the best decision for their families. We welcome the opportunity to discuss options further if owners are leaning toward a gonad-sparing option, offering hysterectomy and vasectomy in addition to traditional sterilization methods. If appropriate, prophylactic gastropexy can be discussed at the same time.
