Should you spay your bitch?

HEALTH ARTICLES

Life prolonging surgery or unnecessary mutilation?

THE GUNDOG CLUB

Hip dysplasia

Protecting hips

Raw food

Spaying

Pippa Mattinson takes a look at the pros and cons of surgery

For some years now, many veterinary surgeons throughout the UK have been recommending the routine spaying of all bitches, which are not going to be bred from. Within traditional gundog circles this philosophy is regarded by some rather cynically as a money making policy, and considered by many to be an unnecessary mutilation of a healthy dog.

Vets tell us that spaying your bitch will protect her against life threatening disease such as mammary cancer. Some breeders counter that the benefits of spaying have been overstated and that this is a major procedure which is risky in itself and has serious unwanted side effects.

Just how common is ‘breast cancer’ in dogs

Let's have a look at some of the facts. On the face of it, the incidence of mammary tumours in unspayed bitches appears to be worryingly high. Several sites that I visited state that a shocking one in four of all unspayed bitches will develop mammary tumours during their lifetime. When looking at statistics they are of course often not as straightforward as they seem. It is difficult to ascertain for example whether this figure is one in four of all dogs refered to a vet, or one in four of all dogs per se. It is perhaps likely that many healthy dogs do not visit a vet at all.

In the 1960s a three year study was carried out collecting data from over 70 veterinary practices in the USA. The results showed an annual cancer incidence rate of 3.8 per 1000 dogs. Fifty one percent (or 1.9 per thousand) of those dogs had mammary tumours. Even taken over the course of a ten (or more) year lifetime, this doesn’t quite equate to a 25% risk. Sadly discrepancies between studies and the way in which data is collected and analysed, does not always help inspire confidence in their findings. On balance however, it is clear that mammary cancer in bitches is far too common, and vets are confident that they have the solution. As vet Jim Tait, practising in Scotland, told The Gundog Club “I have seen plenty of mammary tumours in entire bitches; I have yet to see one in a bitch speyed sooner rather than later”

Differences in susceptibility to cancer may vary from breed to breed, between large dogs and small, between purebred and crossbred dogs (one study showed that the risk doubles for purebred dogs) and depending on environmental influences. One study showed that unspayed bitches who were thin as puppies had half the risk of developing mammary tumours as those that were not thin as puppies. Some studies are carried out on a very small number of subjects, and some come to different conclusions than others.

What is the outlook for a bitch with mammary tumour(s)

Mammary tumours are the most common tumour referral seen in veterinary practice in the UK and 50% of all canine mammary tumours are malignant (cancerous) In addition, 50% of these will already have spread by the time surgery is undertaken. Once the disease has reached this stage, the outlook is depressing. Invasive surgery, followed by radiation therapy or chemotherapy may be needed, treatments not available at all centres, and even then in 40-60% of cases the dog will lose her fight for life within two years. Just as in humans, there appears to be a genetic element in the risk factors for canine mammary tumours. If siblings of your dog or her mother, have developed mammary tumours, then your bitch is at greater risk. This genetic component is presumably why pedigree dogs are also at increased risk

The benefits of spaying

There is no doubt that the incidence of this devastating disease can be almost completely eradicated if the female dog has her ovaries and uterus removed completely before she is sexually mature. Spaying before the first season reduces the risk of mammary tumours in your bitch to almost zero. Spaying between the first and second seasons reduces the incidence of mammary tumours to 7%. Spaying after the second season confers no real benefits in terms of prevention of this disease.

Spaying also offers the dog protection against pyometra (infection of the uterus) and of course has the added advantage for the owner who does not wish to breed, of removing the heat cycle so that the bitch can be worked/taken out in public, all year round.

Most vets recommend that you spay your bitch after her first season to give her time to mature a little without raising the risk unneccessarily

The disadvantages of spaying.

Spaying your bitch is a relatively safe operation, though it carries with it a slightly increased risk of incontinence in the bitch afterwards. She is also likely to experience permanent changes in coat condition which may be unacceptable to some owners, particularly those who are ‘showing’ their dogs. Jim points out that these coat changes are most common in spaniels which still have their puppy coats. There is also a perception that the bitch who is spayed very young may develop mentally in a different way from the entire bitch, perhaps altering her drive and potential in competitive fieldwork, though I could not find any concrete evidence for this. Nor is such evidence is likely to be forthcoming as gundogs do not complete their training before their second heat.

Selecting which bitches to spay

Because the competitive gundog does not reach or show her full potential until after the optimum time for spaying, selecting which bitches to spay and which bitches to breed from is problematical. In addition, some evidence suggests that being bred from on more than one occasion will also decrease the likelihood of mammary tumours developing in your bitch, in a similar way as pregnancy and breastfeeding does in humans.

Removing ovaries and uterus as a means of enhancing and prolonging a working dog’s life is unlikely, therefore, to become popular amongst serious field triallers and dog breeders.

A long and healthy life

However, the evidence for the benefits of spaying for the pet dog or for the shooting companion who is not intended to be bred from seems very strong. If your dog falls into this latter category, then the evidence suggests that having her spayed soon after her first season will greatly increase her chances of a long and healthy life. Whether you view such intervention as a ‘mutilation’ or as a ‘life-saver’ is very personal matter and a choice that each dog owner has to make for themselves.

This article is intended to be a summary of the available information and is not a substitute for veterinary advice. If you have any concerns about your dog’s health, or to find out more about the benefits and disadvantages of spaying your bitch, you should contact your veterinary surgeon.