Early Spay or Neutering of Labradors

When should I spay-neuter my puppy?

Spay or Neutering your puppy – When Should You do it?

Most people hear that you should spay or neuter your puppy as soon as possible (as young as 6 months old), so as to diminish the unwanted puppy population.  While we agree that there is unfortunately a growing population of unplanned puppies, there are also valid arguments for waiting to spay or neuter a dog, that affect its lifetime health.  The article below covers the scientific evidence behind those arguments.

-Endless Mt. Labradors

 A great video to watch on this subject!

Early Spay-Neuter Considerations for the Canine Athlete

One Veterinarian’s Opinion

© 2005 Chris Zink DVM, PhD, DACVP


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.

Doc pup-Endless Mt. Labradors

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 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 ovariohysterectomy 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.

And, cosmetically, if you want your dog to look like the beautiful parents of your pup. Here’s an example of two littermates, one spayed between 6-12 mos, the other never spayed (went into a breeding program) Note the incredible development stagnation of the one spayed early:

(End of article)

***We recommend not spaying or neutering before 18-24 mos since the growth plates are not growing until that time. If you do, you will have unstable joints and be more susceptible to cruciate ligament tears, ACL issues, hyperextension, hip dysplasia and elbow dysplasia. Also, don’t forget, hormones also contribute to how your dog LOOKS. (Imagine cutting off an 11-year-old boy’s hormones…where would that 25 year old be???) Structural growth is done by 24 mos. of age in canines…and the third year they really muscle out, chest drops, head comes in. If you neuter/spay early, your dog will be dwarfed, and will NOT look like its parents. Do not fall for the false “he’ll get testicular cancer” or “she’ll get breast cancer”… as you can see from the research above, it is just the opposite!!*** (Vets have been giving the HSUS and PETA ‘spay/neuter early’ line for years, only caring about ‘unwanted puppies and kittens” with no consideration for the long-term health of your canine family member. If your vet wants to neuter/spay early, you may want to search out a younger vet, or one familiar with the latest research. Holistic vets are the BEST choice!) We know you all want your dogs to live long, pain-free lives, and to look like the beautiful English labs you know us for!

And remember…altering hormones causes shedding (ask any woman that has had a hysterectomy…hair loss is a side effect)



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

2. http://www.grca.org/healthsurvey.pdf

3. Grumbach MM. Estrogen, bone, growth and sex: a sea change in conventional wisdom. J Pediatr Endocrinol Metab. 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 on peak 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 orchiectomy increases 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. JAVMA 2004;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 carcinoma in the dog. 43 cases (1978-1985). J Vet Intern Med 1987 Oct-Dec;1(4):183-7

11. http://www.akcchf.org/pdfs/whitepapers/Biennial_National_Parent_Club_Canine_Health_Conference.pdf

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 to early 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, and testosterone 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 steroid hormones 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: a retrospective 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 gonadectomy performed at an early age or traditional age in dogs. J Am Vet Med Assoc. 2001 Jan 15;218(2):217-21.

Other articles:




  1. Very interesting article. Thanks for the info.

  2. Thanks for the info because I wanted my little big guy to fully develope.

    1. I have an 8 month old male. Did you have any problems with him marking his territory? Mine is peeing all over my house.

      1. i have an intact male 4 year old pitbull and he does NOT mark in the house. he marks all over the backyard and every couple seconds while we take him for walks, but he doesn’t pee in the house ever. if your intact 8 month male is still peeing in the house (we got out male pit at 7 weeks and he was def. not marking in the house or peeing in the house at 8 mths old), i suggest you increase your training of the dog so that the dog understands (very early on) that is is NOT ok to ever pee in the house, mark in the house, or take a shit in the house. training your dog not to go to the bathroom in the house is the #1 thing that you need to teach your dog cause without it, he’ll never stop doing it in the house.
        btw, i also have a 6-7 mth old female pit who has not been spayed (she JUST started her first period/heat on 4th of july). we got her at age 4 mths and she had not been potty trained at all. she didn’t even understand the concept that you go OUTSIDE to go to the bathroom, so she was much harder to train. at around 5-6 she was totally potty trained by us tho and now at just turning 7 mths old a few days ago, she occasionally will make a mistake and go pee in the house (NEVER poo) near the kitchen door. she gets punished by immediately having a time out in her crate and thru this constant training, she has come to learn that going to the bathroom in the house is very bad and whenever she does accidentally pee in the house now, she gets very upset and will walk herself into the crate because she understands she screwed up.
        you have to constantly train her, every day, if you don’t the dog will continue to mark in the house. i really don’t think your dog is marking due to him being intact, i think the dog is marking because the training needs to be increased. good luck, with constant training, the dog will eventually get better!

  3. I agree. I’ve heard this from other places too.

  4. Thanks so much for this info… most peeps push for early ‘fixing’ but it is obviously needed/stated for population control. As a responsible dog owner looking at my next lab purchase the breeder suggested NOT doing anything until at least 18mths – 24mths because of the growth plate closing time period. So that caused me to do so more searching… am glad to find this article you posted which concurs with her thoughts!

  5. purchase a “belly band” to stop this very normal behavior. Read online about the idea behind it so you know how it works.

  6. Inappropriate marking is a behavioral issue not a normal “rite of passage” for male dogs (females can mark as well). If you do not allow it, it will not happen. Failure to thoroughly clean areas that have been soiled will encourage repeat behavior. Use an enzymatic cleaner like Natures Miracle or equal parts vinegar and water to clean any soiled area immediately.

  7. Scientifically – I have a 5 year old labrador DOG. At about 8 months had to take him to a Vet who is also on faculty at Auburn Vet School.. He was glad to hear that my dog was still intact ( I really hate that term) so that he could more fully develop. Over my wife’s objections, he contains to remain INTACT.

    Two anecdotal comments.
    My dad was a DVM pre PC & Animal Activists. He would perform sterilizations when requested but was never an advocate about the issue.

    Second, any sterilization discussions MUST be tempered by acknowledging the zeal of animal activists.
    I recently discovered just how zealous many of these groups are. I had followed NOLA Lab Rescue on Facebook and had volunteered to drive legs moving rescue dogs
    from Louisiana. A few months ago, they had a young dog needing placement and were going to move him from Louisiana to Michigan. I contacted NOLA and offered a forever home, even offering to drive to Louisiana to pick him up.
    One small problem. My dog is “intact.”. Unless I agreed to cut MY dog’s testicles off, I was not a fit home for this homeless pup. I appealed their decision and was met
    with rather brusk responses. In short, every dog or bitch should be sterilized in order to protect all dogs on the planet (??).
    As a result, the puppy in question was transported in about 10 legs from Louisiana to Michigan (I think) to be placed in a foster home.
    Afterwards, I sent FB private messages to several rescue groups I was following & asked their policies. Each one was pretty much the same.
    So I learned my lesson about many of these advocacy groups.
    Just to make the point that I filter any discussions I see about sterilization knowing how myopic many of these people are.
    In the mean time, my 5 year old remains INTACT!

  8. Getting my first, in house, female lab. What may I expect to deal with having an us spayed female?

    1. We have a blog called “So your do is in heat” check it out!

  9. Interesting article – I have 4 labs – all were spayed/neutered at around 1 yr. All the pups were nice and chunky, English style built but as they matured, 2 of the 4 now look like Field labs- my vet called them. He said there are field and English style so after reading this article, I see why maybe they are long and lean now instead of boxy looking. I will consider waiting for any other labs I get in the future

  10. Very Interesting Topic written by you- i also have a 6 month old English Bulldog female and i didn’t want to spayed my dog.. But this is correct spayed need to be done for adoption purpose.

  11. I have a 4 month old and want to wait to spay so she can fully develop but I fear of Pyometra. I read the risk keeps increasing after her first heat? My vet is pushing for 6 months but one of my clients is a retired surgical vet and says to wait 18-24 months. I just want the best for her, any thoughts?

  12. I have a 7 month old female field labrador. At what age can I expect she will go into her first heat? I have had 2 other labs which were both spayed prior to 12 months.
    I would prefer not experiencing a first heat with my puppy. What is a typical age for labs to experience first heat? I am concerned that this summer, she will be 1 year in July
    she could go into heat awhile we are in our beach community and walking/excercising her on the beach would be a huge issue. Thanks so much.

  13. We didn’t neuter our Labrador until he developed a tumor on his one testicle. He was 10 and 1/2. When he was almost 13 he had cardiac tumor- hemangiosarcoma. I know neutering him increased risk of cancer,,, but wish they could of only removed the affected testicle . Maybe we wouldn’t of lost him suddenly and unexpectedly to hemangiosarcoma cancer of the heart. This info is priceless.

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