Article #1 Neuter Medical Facts by Barbara Andrews

Article #2 Early Spay-Neuter Considerations for the Canine Athlete One Veterinarian’s Opinion by Chris Zink DVM, PhD, DACVP


by Barbara (BJ) Andrews

Should you spay or neuter your dog? Neutering is castration. Spaying is hysterectomy. “Spay”, “neuter”, “get them fixed” – no matter what you call it, those non-threatening acronyms stop vital hormone production.

Surgical castration for your pet?The American Veterinary Medical Assoc. (AVMA) official policy says “Mandatory spay/neuter is a bad idea.” The AVMA has taken this stance in direct contradiction to the Humane Society (HSUS) stated goals which is to end all animal ownership.

No, that’s not shooting themselves in the foot because it’s a long walk to that goal and in the meantime, “Animal Rights” veterinarians make a fortune spaying and neutering every pet they can persuade owners to put under the knife.

AVMA policy is particularly brave because the AVMA is under assault by the newest of the Humane Society’s creations, the HSVA. The AVMA boasts over 70,000 members. No one knows how many members the Humane Society Veterinary Assoc. actually has but with millions of non-taxable HSUS dollars behind it, the Humane Society Vets will probably prevail in the spay-neuter goldmine.

Even so, the AVMA deals HSUS a blow in its straightforward policy statement “potential health problems associated with spaying and neutering have also been identified, including an increased risk of prostatic cancer in males; increased risks of bone cancer and hip dysplasia in large-breed dogs associated with sterilization before maturity; and increased incidences of obesity, diabetes, urinary tract infections, urinary incontinence, and hypothyroidism.” Ref:

Whether/when to spay or neuter has been studied by other veterinary groups. Linda Witouski, TheDogPress Legislative Editor, sent this Journal of American Veterinary Assoc. (JAVMA) report which also points out the myriad of health risks.

Spaying or neutering can cause prostate or bone cancer, obesity, urinary incontinence, thyroid problems, and much more!In a study of well over a million dogs, information on breed, sex, and age was collected and reported to the Veterinary Medical Database between 1964 and 2003. Results—Castrated male dogs were significantly more likely than other dogs to have hip dysplasia (CHD) than other dogs and spayed females were significantly more likely to have cranial cruciate ligament deficiency (CCLD).

Dogs up to 4 years old were significantly more likely to have HD whereas dogs over 4 years old were significantly more likely to have CCLD. In general, large- and giant-breed dogs were more likely than other dogs to have HD, CCLD, or both.

Prevalence of HD and CCLD increased significantly over the 4 decades for which data were examined. There was no data reflecting the decade-by-decade increase but one might suspect that the significantly increased rate of spay and castration procedures may be a factor in the overall forty-year increase. ref: June 15, 2008 Journal of the American Veterinary Medical Association.

Cystitis, urinary incontinence, noise phobias, obesity added to bone and joint problems.

There are other adverse effects of surgical neutering, particularly when the surgery is performed on puppies, obliquely referred to as “early-age” spay/neuter, pediatric spay/neuter, or juvenile spay/neuter, presumably depending on age at which ovariohysterectomy or orchietomy is performed on the puppy. Another study published in the Journal of Am. Veterinary Medicine, noted an “increased rate of cystitis and decreasing age at gonadectomy was associated with increased rate of urinary incontinence. Among male and female dogs with early-age gonadectomy, hip dysplasia, noise phobias, and sexual behaviors were increased, whereas obesity, separation anxiety, escaping behaviors, inappropriate elimination when frightened…”

These are not insignificant problems. Urinary incontinence and uncontrolled elimination will banish a dog to the outdoors and more often than not, to the “shelter.” Hip dysplasia, worsened by obesity, will bring valued family dogs in to the veterinary office where costly hip surgery may be performed. Other dogs, owned by families of lesser means or smaller hearts, will be dumped at the pound. The same can be said of dogs with noise phobias, separation anxieties, and embarrassing sexual behaviors. Dogs that habitually escape will inevitably be run over or taken to the local shelter.

While all agree that surgical castration and hysterectomy are the only viable options for sterilization, Chris Zink DVM, PhD, DACVP explains risks for the canine athlete, covering the subject in an easy to read format.

If you must spay or neuter your dog…

In summary, knowledgeable breeders agree; pets should not be spayed or neutered before puberty and not until growth plates have closed and then only if their behavior becomes an annoyance to the family. Note that onset of puberty varies depending on the breed’s growth rate.

Thanks to the Animal Rights Extremists and the Humane Society of the U.S. (HSUS), none of which rescue, adopt, or shelter unwanted dogs, it is almost impossible to adopt a shelter puppy that isn’t already spayed or castrated. That may have some benefits for adoptive owners but that spay and neuter policy has virtually no benefit to the animal. None whatsoever.

Unwanted pregnancy can be prevented by keeping the animal inside the home or a secure fence. By the way, an electric fence does not prevent other dogs from getting to your female dog!

Whether and When to have surgical sterilization performed should be up to the owner, not the government or local bureaucrats. Who knows more about your dog’s health than your veterinarian? Even though promoting early spay and neuter profits vets in the long run; honest, knowledgeable vets who learn from clinical experience and vet school instead of animal “rights” activists will veto spay/neuter particularly when performed on puppies.

So talk to your vet. Then contact a responsible breeder who is as knowledgeable as your good vet. Breeders have been a little bit brainwashed but if you convince them that you want only to delay premature, risky removal of sex hormone organs, they will listen. And please, don’t buy into the “adopt from a shelter” push. By far, your healthiest, soundest, most reliable and predictable choice is a purebred puppy or retired adult from a knowledgeable breeder.

Your choice should not be limited to a shelter mongrel that may or may not fit your family; that may be in a shelter because of behavior or health problems and certainly not a dog that was subjected to early spay or neuter. You have only to think of the consequences of surgical sterilization in humans to realize why the health is then protected by hormone prescriptions.

The spay/neuter choice should be yours and it should be an informed choice, not an automatic compliance of something you don’t understand, the results of which could keep you in and out of the vet’s office for the lifetime of your pet!

Early Spay-Neuter Considerations for the Canine Athlete – One Veterinarian’s Opinion

Those of us with responsibility for the health of canine athletes need to continually read and evaluate new scientific studies to ensure that we are taking the most appropriate care of our performance dogs. This article provides evidence through a number of recent studies to suggest that veterinarians and owners working with canine athletes should revisit the standard protocol in which all dogs that are not intended for breeding are spayed and neutered at or before 6 months of age.

Orthopedic Considerations

A study by Salmeri et al in 1991 found that bitches spayed at 7 weeks grew significantly taller than those spayed at 7 months, who were taller than those not spayed (or presumably spayed after the growth plates had closed).(1) A study of 1444 Golden Retrievers performed in 1998 and 1999 also found bitches and dogs spayed and neutered at less than a year of age were significantly taller than those spayed or neutered at more than a year of age.(2) The sex hormones, by communicating with a number of other growth-related hormones, promote the closure of the growth plates at puberty (3), so the bones of dogs or bitches neutered or spayed before puberty continue to grow. Dogs that have been spayed or neutered well before puberty can frequently be identified by their longer limbs, lighter bone structure, narrow chests and narrow skulls. This abnormal growth frequently results in significant alterations in body proportions and particularly the lengths (and therefore weights) of certain bones relative to others. For example, if the femur has achieved its genetically determined normal length at 8 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. In addition, sex hormones are critical for achieving peak bone density.(4) These structural and physiological alterations may be the reason why at least one recent study showed that spayed and neutered dogs had a higher incidence of CCL rupture.(5) Another recent study showed that dogs spayed or neutered before 5 1/2 months had a significantly higher incidence of hip dysplasia than those spayed or neutered after 5 1/2 months of age, although it should be noted that in this study there were no standard criteria for the diagnosis of hip dysplasia.(6) Nonetheless, breeders of purebred dogs should be cognizant of these studies and should consider whether or not pups they bred were spayed or neutered when considering breeding decisions.

Cancer Considerations

A retrospective study of cardiac tumors in dogs showed that there was a 5 times greater risk of hemangiosarcoma, one of the three most common cancers in dogs, in spayed bitches than intact bitches and a 2.4 times greater risk of hemangiosarcoma in neutered dogs as compared to intact males.(7) A study of 3218 dogs demonstrated that dogs that were neutered before a year of age had a significantly increased chance of developing bone cancer.(8) A separate study showed that neutered dogs had a two-fold higher risk of developing bone cancer.(9) Despite the common belief that neutering dogs helps prevent prostate cancer, at least one study suggests that neutering provides no benefit.(10) There certainly is evidence of a slightly increased risk of mammary cancer in female dogs after one heat cycle, and for increased risk with each subsequent heat. While about 30 % of mammary cancers are malignant, as in humans, when caught and surgically removed early the prognosis is very good.(12) Luckily, canine athletes are handled frequently and generally receive prompt veterinary care.

Behavioral Considerations

The study that identified a higher incidence of cranial cruciate ligament rupture in spayed or neutered dogs also identified an increased incidence of sexual behaviors in males and females that were neutered early.(5) Further, the study that identified a higher incidence of hip dysplasia in dogs neutered or spayed before 5 1/2 months also showed that early age gonadectomy was associated with an increased incidence of noise phobias and undesirable sexual behaviors.(6) A recent report of the American Kennel Club Canine Health Foundation reported significantly more behavioral problems in spayed and neutered bitches and dogs. The most commonly observed behavioral problem in spayed females was fearful behavior and the most common problem in males was aggression. (12)

Other Health Considerations

A number of studies have shown that there is an increase in the incidence of female urinary incontinence in dogs spayed early (13), although this finding has not been universal. Certainly there is evidence that ovarian hormones are critical for maintenance of genital tissue structure and contractility.(14, 15) Neutering also has been associated with an increased likelihood of urethral sphincter incontinence in males.(16) This problem is an inconvenience, and not usually life-threatening, but nonetheless one that requires the dog to be medicated for life. A health survey of several thousand Golden Retrievers showed that spayed or neutered dogs were more likely to develop hypothyroidism.(2) This study is consistent with the results of another study in which neutering and spaying was determined to be the most significant gender-associated risk factor for development of hypothyroidism.(17) Infectious diseases were more common in dogs that were spayed or neutered at 24 weeks or less as opposed to those undergoing gonadectomy at more than 24 weeks.(18) Finally, the AKC-CHF report demonstrated a higher incidence of adverse reactions to vaccines in neutered dogs as compared to intact.(12 )I have gathered these studies to show that our practice of routinely spaying or neutering every dog at or before the age of 6 months is not a black-and-white issue. Clearly more studies need to be done to evaluate the effects of prepubertal spaying and neutering, particularly in canine athletes. Currently, I have significant concerns with spaying or neutering canine athletes before puberty. But of course, there is the pet overpopulation problem. How can we prevent the production of unwanted dogs while still leaving the gonads to produce the hormones that are so important to canine growth and development? One answer would be to perform vasectomies in males and tubal ligation in females, to be followed after maturity by ovario hysterectomy in females to prevent mammary cancer and pyometra. One possible disadvantage is that vasectomy does not prevent some unwanted behaviors associated with males such as marking and humping. On the other hand, females and neutered males frequently participate in these behaviors too. Really, training is the best solution for these issues. Another possible disadvantage is finding a veterinarian who is experienced in performing these procedures. Nonetheless, some do, and if the procedures were in greater demand, more veterinarians would learn them. I believe it is important that we assess each situation individually. For canine athletes, I currently recommend that dogs and bitches be spayed or neutered after 14 months of age.


1. Salmeri KR, Bloomberg MS, Scruggs SL, Shille V.. Gonadectomy in immature dogs: effects on skeletal,physical, and behavioral development. JAVMA 1991;198:1193-1203


3. Grumbach MM. Estrogen, bone, growth and sex: a sea change in conventional wisdom. J Pediatr EndocrinolMetab. 2000;13 Suppl 6:1439-55.

4. Gilsanz V, Roe TF, Gibbens DT, Schulz EE, Carlson ME, Gonzalez O, Boechat MI. Effect of sex steroids onpeak bone density of growing rabbits. Am J Physiol. 1988 Oct;255(4 Pt 1):E416-21.

5. Slauterbeck JR, Pankratz K, Xu KT, Bozeman SC, Hardy DM. Canine ovariohysterectomy and orchiectomyincreases the prevalence of ACL injury. Clin Orthop Relat Res. 2004 Dec;(429):301-5.

6. Spain CV, Scarlett JM, Houpt KA. Long-term risks and benefits of early-age gonadectomy in dogs. JAVMA2004;224:380-387.

7. Ware WA, Hopper DL. Cardiac tumors in dogs: 1982-1995. J Vet Intern Med 1999 Mar-Apr;13(2):95-103

8. Cooley DM, Beranek BC, Schlittler DL, Glickman NW, Glickman LT, Waters D, Cancer Epidemiol Biomarkers Prev. 2002 Nov;11(11):1434-40

9. Ru G, Terracini B, Glickman LT. Host related risk factors for canine osteosarcoma. Vet J. 1998 Jul;156(1):31

10. Obradovich J, Walshaw R, Goullaud E. The influence of castration on the development of prostatic carcinomain the dog. 43 cases (1978-1985). J Vet Intern Med 1987 Oct-Dec;1(4):183-7


12. Meuten DJ. Tumors in Domestic Animals. 4th Edn. Iowa State Press, Blackwell Publishing Company, Ames,Iowa, p. 575

13. Stocklin-Gautschi NM, Hassig M, Reichler IM, Hubler M, Arnold S. The relationship of urinary incontinence toearly spaying in bitches. J. Reprod. Fertil. Suppl. 57:233-6, 2001

14. Pessina MA, Hoyt RF Jr, Goldstein I, Traish AM. Differential effects of estradiol, progesterone, andtestosterone on vaginal structural integrity. Endocrinology. 2006 Jan;147(1):61-9.

15. Kim NN, Min K, Pessina MA, Munarriz R, Goldstein I, Traish AM. Effects of ovariectomy and steroidhormones on vaginal smooth muscle contractility. Int J Impot Res. 2004 Feb;16(1):43-50.

16. Aaron A, Eggleton K, Power C, Holt PE. Urethral sphincter mechanism incompetence in male dogs: aretrospective analysis of 54 cases. Vet Rec. 139:542-6, 1996

17. Panciera DL. Hypothyroidism in dogs: 66 cases (1987-1992). J. Am. Vet. Med. Assoc., 204:761-7 1994

18. Howe LM, Slater MR, Boothe HW, Hobson HP, Holcom JL, Spann AC. Long-term outcome of gonadectomyperformed at an early age or traditional age in dogs. J Am Vet Med Assoc. 2001 Jan 15;218(2):217-21

© 2005 Chris Zink DVM, PhD, DACVP