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Spay & Neuter

Have you ever thought about why we started to spay and neuter pets?  Mainly, it was a concern for unwanted stray animals overwhelming shelters.  Some pets, like rabbits and cats have seriously impressive reproductive abilities and can create significant populations in a very short time.

Consider this comparison:

  • The female cat comes into heat every 3 to 4 weeks from February to October, with each heat lasting roughly a week.  Cats ovulate after they have mated, significantly improving the chance of a successful pregnancy.  One intact female cat of breeding age (from 4 months to death) and her intact offspring could number 420,000 within 7 years

  • Dogs have a fairly short fertility period, just 2-5 days every 6 months or so.  An intact dog and her offspring can produce up to 508 dogs within 7 years

In Europe, dogs are routinely kept intact for their lifetimes yet they do not have an overwhelming problem of stray, unwanted animals.

When animals are neutered before skeletal maturity, no more sex hormones are released.  The effect is to leave growth plates open and not support the developing joint as well. Legs grow extra long but with thin, light bones, chests remain narrow along with skulls. The loss of sex hormones also drastically reduces metabolism causing a high incidence of obesity in altered dogs.

This means that bones and joints are 'out of sync with each other and the angles between bones is changed from the normal, sturdy structure - what we think of as good conformation is orthopedic soundness.  A longer tibia puts more stress on the CCL ligament at the knee.  Combine this with an over weight dog and you have knee problems.

Then there is the cancer consideration.  Neutering your dog early reduces the risk of breast cancer in females and prostate cancer in males - fairly benign and treatable conditions, if they occur.  But neutering significantly contributes to other sudden, untreatable, deadly cancers.

Behaviour is another common reason for early spay or neuter, yet the studies show that the male dogs with aggression issues are the neutered males.  In fact, early spay or neuter contributes to fear of storms and reactivity.  And neutering a male does not change his sex behaviors.

The list goes on.  Incontinence, thyroid disease, pancreatitis, vaccine reactions and a host of auto-immune diseases are more likely in spayed or neutered dogs.

Given all of this information, we must ask, "Is it feasible for the average owner to manage an intact dog for its lifetime?

How much trouble is it really to keep a dog intact?  It's actually very easy.  Millions of people (especially in Europe) do this without advanced degrees or other training. For females, you will need to manage a day or two of spotting at the beginning of the heat cycle, twice a year.  A few pairs of "culottes" or period panties easily handle the mess.  Just throw them in the wash and reuse the next day.  Our female prefers to stay close to home, even in her kennel on these days.

Owners of non-breeding male dogs teach their dogs that mounting is unacceptable (puts you in your crate), the same as peeing on furniture or people's trousers.  For breeding males, we teach them that mounting is encouraged in specific circumstances, in the bathroom, with this specific bath mat, so that we can either breed or collect semen.

No dogs should run wild through the neighborhood, which eliminates unwanted breeding.  If you are walking on leash with your female in heat you will notice nothing - unless there are a LOT of dogs around.  It can be a bit of a challenge at dog shows when the female in front of your dog is in heat - but that happens everyday, since they must be intact to show.  All the more reason to have your dogs trained about what is acceptable.

What is challenging, even for the best trained dogs and seasoned owners, is preventing unwanted breeding when you keep both male and female dogs intact at home.  This is a difficult situation for perhaps 10 days, twice a year, with crying, scratching, circling, distraught dogs. 

If you can, send the male to a friend's place for a few weeks. Otherwise, the only safe practice to prevent breeding is to keep 2 closed, locked doors between male and female at all times.  It's not so tough if you have just a couple people and a small, simple layout.  If you have a larger family or regular visitors and a layout with many doors to access the yard, you'll need to be extra vigilant. Dogs can be very stealthy when they notice a breeding opportunity and once they are tied, you are committed.  Morning after medication is not advised, by many vets.

I feel very strongly that the debate is now over.  Virtually all recent studies exclaim the benefits of keeping your dog intact.  

Scientific Studies

Dr. Chris Zink, is an expert in dog athletic injuries and rehabilitation.  She has written recently about the benefits of delayed spay and neuter.  Here are some highlights from her research and experience.

  • Spayed & Neutered dogs have a signficiantly higher prevalence of CCL rupture, a knee injury which requires surgery and long rehab.  It is fairly common in Entlebuchers that do agility work.

  • Dogs neutered or spayed dogs are 1.5 times more likely to develop hip dysplasia, a crippling and painful dislocation of the hip joint.

  • Spayed and neutered dogs have 3.1 times higher incdence of patellar luxation, a shifting knee cap.

  • Spayed females had more than 5 times greater risk of developing cardiac hemangiosarcoma than intact bitches.

  • Spayed females had 2.2 times increased risk for developing splenic hemangiosarcoma than intact females.

  • Spayed/neutered dogs had a 2.2 times higher risk of developing bone cancer than intact dogs.

  • Neutered dogs had a 2.8 times higher risk for developing prostate cancer than intact dogs.

  • Neutered dogs had a 4.3 times higher risk of developing prostate carcinoma than intact dogs.

  • Neutered dogs had a 3.6 higher risk for developing transitional cell carcinoma of the bladder than intact dogs, and a 3 times greater risk of developing any bladder tumor.

  • Early neutered male Golden Retrievers were 3x more likely to be diagnosed with lymphoscarcoma than intact males, and late-spayed females were significantly more likely to develop hemangiosarcoma and mast cell tumor than intact females.

  • In a survey of 2505 Vizslas, dogs spayed or neutered dogs at any age were found to have a significantly higher risk of mast cell cancer, hemangiosarcoma, lymphoma and all cancers together than intact dogs. In this study, the risk of gonadectomized dogs developing one of the above cancers was significantly higher than the risk of an intact female developing mammary cancer.

  • Further, the younger the age at gonadectomy, the earlier the mean age at diagnosis of mast cell cancer, hemangiosarcoma, lymphoma, and all cancers combined.

  • The overall risk of any bitch getting a mammary tumor was only 0.2%,  compared with the 200 to 400% increased risk of other cancers in spayed females.

  • Early age gonadectomy was associated with an increased incidence of noise phobias and undesirable sexual behaviors, such as mounting.

  • Vizslas gonadectomized at ≤ 6 months, between 7 and 12 months, or at > 12 months of age had significantly increased odds of developing fear of storms, compared with the odds for sexually intact dogs.

  • Those gonadectomized at ≤ 6 months of age had significantly increased odds of developing a behavioral disorder.

  • Significantly more behavioral problems were seen in spayed and neutered bitches and dogs, with fearful behavior being most common in spayed bitches and aggression in neutered dogs.

  • German Shepherd Dogs spayed between 5-10 months of age had significantly increased reactivity.

  • A recent study of more than 13,500 dogs showed no association between gonadectomy and aggression of dogs towards familiar people and other dogs.

  • However, there was a significant increase in the odds of moderate or severe aggression toward strangers for dogs gonadectomized at 7 to 12 months of age.

  • Female, and sometimes male, dogs that are spayed/neutered before puberty have an increased risk of urinary incontinence and it is more severe in bitches spayed earlier.

  • Spayed female dogs displayed a significantly higher risk of hypothyroidism when compared to intact females.

  • Neutered females had a 22 times increased risk of developing fatal acute pancreatitis as compared to intact females.

  • Risk of adverse reactions to vaccines is 27 to 38% greater in neutered dogs as compared to intact.

  • In a study of female Rottweilers there was a strong positive association between retention of the ovaries and longevity.

  • A study of 90,090 dogs revealed that neutered and spayed dogs had a significantly increased risk of atopic dermatitis, autoimmune hemolytic anemia, hypoadrenocorticism, hypothyroidism, immune-mediated thrombocytopenia, and inflammatory bowel disease than intact dogs.

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