Monday 11 December 2017

Sometimes illness and death are not accidental

By Pete Wedderburn - ANimal Doctor

Pete Wedderburn
Pete Wedderburn

Euthanasias are part of my routine workload as a vet, but this one was particularly difficult.

Milly the Cavalier King Charles Spaniel was a seriously ill nine year old dog, and her twelve year old owner, Amy, was distraught. I'd explained that Milly was suffering from heart disease caused by a leaky valve, and that although drugs had helped her enjoy an extra two years of good quality life, they weren't working any more. Milly was coughing almost continuously, and was struggling to catch her breath. If we didn't help her to die peacefully, she'd suffer immensely, and she'd pass away anyway. There was nothing more that could be done to help her.

"But WHY does she have heart disease?", Amy wailed. I glanced at Amy's mother as I said "It's just something that happens". As I spoke, I could feel my nostrils flaring. This is an innate part of my unconscious body language that I can't control. My wife tells me that my nostrils always flare when I am not telling the full truth, even when the "untruth" is something as harmless as a practical joke.

I knew that it was not entirely accurate to tell Amy that Milly's heart disease "just happened", and my subconsciousness was not letting me get away with it. The truth was that, like many illnesses in pedigree dogs, heart valve disease in Cavaliers is a result of human inaction.

Pedigree dog breeds are a human invention. If left to breed on their own, all dogs would be cross breds, probably resembling fox-type wild dogs, or the type of collie-cross street dog that's commonly seen in Asia. Instead, humans have stepped in over the centuries, carefully choosing which dogs are allowed to breed together. By choosing dogs with particular appearances, the various separate types of dog breeds have been created. The variety is immense: from Cavalier King Charles Spaniels to Great Danes to Chihuahuas. The human impact on the shape, size and appearance has been remarkable.

However there is a serious problem with deliberately selecting a narrow number of dogs for breeding (i.e. only the ones with the particular type of appearance that's sought). Just as the desirable visible characteristics are selected, so are some undesirable but invisible faults. In the Cavalier breed, one of these "faults" is an increased tendency for the heart valves to age prematurely.

Heart valves are like fine, flexible rubber sheets inside the heart chambers that close and open as the heart beats. They let blood flow through in one direction, and prevent blood from flowing back in the other direction. As the body ages, it's normal for heart valves to gradually degenerate, becoming less elastic and less flexible, just like other tissues in the body (skin is the most obvious example). As heart valves change in this way, they stop creating a tight seal, allowing blood to leak through the gap. This leak creates a hissing noise that can be heard with a stethoscope: it's called a "heart murmur". In most dogs, heart murmurs are rarely seen, and even very elderly dogs often have healthy hearts.

In Cavaliers, however, the heart valves start to degenerate when dogs are young: 50% have a heart murmur by the age of five, and 90% have heart valve disease by the age of ten. It's almost "normal" for Cavaliers to develop heart failure in middle age, and it's common for dogs to die of heart disease before they reach ten years of age, like Millie.

In Denmark, the Cavalier King Charles Spaniel dog breeding fraternity has taken this disease seriously. For a number of years, it has been compulsory to have Cavaliers' hearts checked by a cardiologist before using them for breeding. Dogs that have not been tested cannot be used for breeding. Dogs that discovered through testing to have heart murmurs cannot be used for breeding. So only dogs with healthy hearts are allowed to produce puppies. The results have been remarkable, with a 70% reduction in the rate of heart failure in the breed.

In the UK and Ireland, there has been much talk about the need to take some action, but other than the efforts of a few individuals to improve their own breeding stock, nothing official has happened. The UK Kennel Club has been saying for eight years that a scheme will be set up, but so far, no scheme is in place. As a measure of the strong feeling amongst pet owners who feel aggrieved by the situation, a recent online petition asking the Kennel Club to take action has gathered over 25000 signatures. People who have owned Cavaliers that have developed heart failure feel incensed that more has not been done.

The Kennel Club has responded by explaining that they are currently discussing the protocol for heart testing which exists in Denmark in the hope that this will further the development of an agreed scheme in the UK. And in due course, the hope would be that a similar scheme will start in Ireland.

Meanwhile, when Amy asked me why Millie had heart disease, I really should have said "because the people who organise the breeding of puppies of her breed haven't done enough to make sure that dogs like Millie have healthy hearts". And I would have been able to say that without flaring my nostrils.

Wexford People

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