Tuesday, November 18, 2014

Diseases that undesexed dogs may suffer from

When I was a university student, one of the few surgical procedures that we had to perform regularly, was the "desexing" procedure for both male and female dogs and cats.  The reason?  This was going to be the most common surgery of general veterinary practitioners.

 Is it going to stay like this as the veterinary profession forges into the future?

My opinion?

 No -

I foresee that, like vaccination, we will be desexing fewer younger animals. And we will be performing alot more emergency surgeries on very sick older dogs, with all of the risk that it entails.


There are currently multiple studies that seem to raise more questions, than provide answers on this controversial issue of whether to desex or not.

As a vet, I applaud any research that investigates the potential causes of disease in our animals.

What we do know is that there appear to be significant breed differences of the effect of desexing on specific cancers and joint problems.

There is no dispute that the act of desexing (male and female), predominantly large breed dogs, and the age that this occurs, affect our animals in ways that was unexpected.

Sadly, many online authors are extrapolating the published results from one breed to another, and making broad blanket "scientific"  statements.

If you want to know more about desexing (pros and cons), then you can visit my website.

My position (at time of posting this, so it is subject to change) - each pet is individually assessed on whether the procedure is the right thing for them or not.  If I have any doubt based on current knowledge, then I will do what is the best thing for that pet.

In other words, I do not perform unnecessary procedures.

Many of the studies are from universities, and here I see a flaw in the argument.  These studies cite a low incidence of pyometron and breast cancer in undesexed dogs, and thus, downplay the seriousness of these very real, life threatening conditions. Many online "scientific" opinion pieces also downplay  how common  these serious diseases are.

Problem is, treatments for pyometron and breast cancers are commonly performed in general practice (what is often called primary care centres) with many vets rarely, if ever,  needing to refer pets to a specialist for this surgery. Breast cancer and pyometron patients do die.... but sadly, they do not make it into the "statistics" of how common a disease is or isn't.

However, with respect to many cancers, such as hemangiosarcoma or lymphoma, or cruciate disease - these are common referrals due to the nature of the treatment required. Only a handful of vets in general practice are set up to deal with chemotherapy drugs (requiring special equipment) and advanced orthopaedics.

Does this mean I don't take any credence to these studies  about the effects of desexing on our pets?

Teddy- rest in peace sweet man - 2009
Of course not!  My own dog, Teddy, died from lymphoma in 2009, and like any other pet owner, I also wonder what caused it.   He was not desexed until he was 2.5 years old (simply because I never got around to it.  I do not believe, nor do I have any evidence to believe, that desexing him caused his cancer.

What I would like to see is the inclusion of cases from the general population, and - an acknowledgement that there are pros and cons in either decision - whether to desex or not. 

Let me talk about three very common diseases that undesexed dogs may suffer from. 


This is a common condition of usually older female dogs, with a typical set of signs. 
A Friday night Pyometron surgery in a 12 year old  cattle dog. The uterus
ruptured after I had removed it from the dog. It weighed
over 2 kg.

Basically, it is a pus filled uterus as a result of the hormonal influences.  The signs are seen within three weeks of a dog's "heat" cycle, with the signs including
- lethargy
- drinking more than usual
- a distended abdomen
- with or without a vaginal discharge

And, it can be fatal. 

Treatment, in general is emergency surgery (desexing), but there are the options of medical treatment too in dogs who are intended for future breeding.

The surgery is technically difficult, there is a high risk of the uterus rupturing at any time of the surgery, and often, the female dog is systemically toxic and sick with liver/kidney damage.

Half of the pyometron cases I see are euthenased, primarily, to the cost of the surgery and the age of the dog.  On average, it is 4-5 times the cost of a routine desexing. On the surface it may appear to be the same surgery, but it actually isn't.  The incision is usually 3 times longer, the uterus is significantly larger, and much more friable.  The dog itself, is sick and old.

This disease is preventable by desexing when the dog is healthy (irrespective of age). 

As an aside:  There are suggestions in many anti-desexing web pages about "partial spay" or "ovary sparing spay".  These are surgeries that leave 1 or both ovaries, but with the removal of the uterus.  Unless the entire uterine tract is removed (technically difficult), there is a high risk of  "stump pyometron".   The problem also lies in how to mark the dog as having undergone this procedure (in the event of rehoming in the future).

How common is this?  More than 50% of undesexed dogs older than 7 years of age are likely to get this condition.

We see approximately 4 cases a year, with a euthanasia rate of 50%.  Very sad.

Ovarian & Testicular Cancer

As the ovary and the testicle are technically similar tissue, I have put these two conditions under the one heading.
Whilst this is the size difference in a cryptorchid surgery, the same
size variation applies with testicular cancer too.

I had my first ever ovarian cancer patient three weeks into my first job in 1990.  It has haunted me since, as it came as an after hours emergency case, collapsed and died within 20 minutes.  The distraught owner blamed me for not saving her dog.  The ovarian cancer was identified via  a post mortem. There was nothing I could have done to save her.

It has still haunted me. I didn;t cause the cancer, and in theory, it was a preventable problem. However, it died and I could not save it.

Testicular cancers are a little easier to diagnose (thanks to the location of the testicle).  Usually, there is an asymmetry in the testicle size, which is very obvious to anyone who looks.

Herein lies the problem - how many pet owners check their dog's balls?

In my area, very few, as I am often pointing out the size difference to owners in a consultation (often they are in because of skin problems or sneezing, or something equally non-serious). It is a difficult conversation advising surgery in an older dog  - after all, the dog has made it to that age without the need for desexing. 

How common is ovarian cancer?  Diagnosis is problematic, like with us, so the true incidence is unknown. It is listed as uncommon.

How common is Testicular cancer?  Diagnosis is easy, and is common in older (than 7 years) undesexed male dogs.  Fortunately, in most cases, surgery (desexing) , is curative.

 I see 1 to 2 cases each year.

Prostatic Infection

In undesexed male dogs, the hormone testosterone enlarges the prostate gland (which sits on the base of the neck of the bladder).  With hormonal stimulation, this gland enlarges (called Benign Hypertrophy), which causes few problems.  The dogs may have trouble passing a bone impacted poo (one of the many reasons I am opposed to bones in dogs), and may dribble wee occasionally.  These are usually not life threatening problems.

However, this enlargement can get infected. It can form into a prostatic abscess, or worse, into multiple prostatic abscesses or cysts. The largest prostate abscess I have palpated was the size of a honey dew melon in a bull dog. 

Diagnosis occurs as a result of a combination of tests, including  palpation of the abdomen, abdominal radiographs, abdominal ultrasound, and then performing a prostatic wash.  A culture is performed to identify the best antibiotic to use.  In my latest case, the bacteria was actually resistant to the fluroquinolone most commonly used for prostatic infections, so fortunately, with the culture results, we were able to use the right antibiotic that would get into the tissue.
Male dogs can die from this condition - from either the abscess rupturing internally, urinary obstruction or septicemia (septic shock).  Treatment involves desexing ( or the suprelorin implant), aggressive and long term antibiotics based on urinary culture and sensitivity.  Sometimes, surgery is required to drain the abscess (marsupialise it).

How common is prostatic disease?  I see a case each 2 to 3 months.  (about 4 cases a year)
Desexing is curative and preventative

Now don't think for a minute that these are the only conditions that an undesexed pet can get. There are alot more, including

- skin conditions 
- mammary cancer
- vaginal polyps
- perianal adenomas and adenocarcinomas
- perineal hernias
and this is without thinking too hard!

I am Dr Liz, the mad vet from Bellambi. I am always happy to discuss the pros and cons from desexing your pet with you.  There are many factors to consider, such as your pets breed and lifestyle. 

What I am trying to say... probably poorly is....speak to your vet, the one you trust, about what is the right thing for your pet.  They really have their welfare at heart.