Inbreeding and lifespan...

[Kara31191]

I was thinking about lifespans of different animals the other day, and I was wondering what the effects of inbreeding have done for species like budgies, dogs and cats.

Here's what I'm basing my opinion on: In theory, dogs all have different lifespans and are prone to different diseases. Golden retrievers are known for cancer, and while I know it's body shape that causes hip and back problems, genetics have proven to play a part in it; for example, dachshunds.

So do you think that the differing lifespan in dogs is a result of humans trying to make a myriad of breeds?

I could do some research on the above question and try to write a good paper (for pure fun... yeah go figure), but I was also thinking about parrots and cats.

Some cat could live into their early twenties. Why is it that cats can and dogs can't? I'll bet there's a reason. I'm thinking that genetics are still kicking in. If I truly think about it, most dogs were inbred SOMEWHERE down the line. I wonder if that changes anything? Could we not breed dogs that had certain diseases and improve the breed for the most part?

Also, with parrots. Budgies are pretty much the MOST inbred bird there is. Canaries, finches and budgies all have relatively short lifespans. While you could argue it's the SIZE of the bird, think about the parrotlet, and lovebird. They are not known to be inbred and inbred as much as the first three I listed and have MUCH longer lifespans!

Maybe this is stupid... I was just kind of thinking. Feel free to give me resources, opinions, approve or disapprove... Anything?

Thanks guys!

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[akitavet]

Hmmm.... I think that can be true when you are talking about inherited breed problems like megaesophagus in GSD, Epilepsy in Border Collies, MVD in CKCS. These are catastrophic conditions that would dramatically effect lifespan. Otherwise generally speaking, dog lifespan seems to scale pretty linearly with size. I guess the other thing we have to factor in is that dogs dont die naturally. For the most part, they are euthanized. In "the wild" (I put this in quotes because I personally dont believe that there is any wild for dogs. I believe that dogs only exist as domesticated animals) large breeds would die off when they suffered from crippling orthopedic issues, but small breeds would have been prey anyway.

 

[athenaparthenos]

Some cat could live into their early twenties. Why is it that cats can and dogs can't?

I've met a 20-year-old Pomeranian before. Mind you, he was rather alarming because he trembled nonstop, seemed unaware of his surroundings, and just looked like he could have stood to pass on a couple years back... but, he kept on trucking until almost 21. Very rare, but in the small breeds it does happen occasionally.

 

[Kara31191]

That's why I was wondering... It's a confusing topic I was looking for opinions on. I know, I'm going to bring up that dachshund again, but why is it that they, a smaller breed, may only live 9-15 years and golden retrievers are about 10-12 years. American cocker spaniels are typically 10-12 years and they are smaller than golden retrievers.

Basically, through all my rambing, I'm questioning why lifespans differ in all breeds and species? Why do our bodies fail (humans and animals) and how is this related to what we do? Diet? Genetics? Or is it what humans have done to life and this planet?

Take a look:
http://www.sln.org/guide/sowd/Max_Animal_Life_Span.pdf

I think these should be the AVERAGE life spans... right? I'm trying to see if this is a legitimate source, but it seems like it!

 

[david594]

Why can a flying squirrel that weights 60-75 grams live from 10-15 years in captivity but a similar size mouse can only live a few years?

 

[akitavet]

okay well we cant be comparing squirrels and mice or different species of birds in the same breath as comparing breeds of dogs.

 

[Habibti]

Statistical analysis regarding the effects of height and weight on life span of the domestic dog
Research in Veterinary Science
Volume 82, Issue 2, April 2007, Pages 208-214

This study was undertaken to determine the association between life spans and breed size in the dog, based upon data derived from the pet population. Seventy-seven American Kennel Club breeds were analyzed with data collected for more than 700 dogs. Multiple linear regression analysis was carried out with longevity as the dependent variable and height or weight as the independent variable. A negative correlation was observed between height and longevity (r = &#8722;0.603, p < 0.05), and between weight and longevity (r = &#8722;0.679, p < 0.05). Weight was the significant predictor of life span (p < 0.001), revealing that breeds smaller by weight generally live longer than heavier breeds. These data form the ground work for investigations of aging utilizing the dog as a model and provide owners with a quantitative method for predicting lifespan of dog breeds, thereby aiding in pet selection.

Longevity of British breeds of dog and its relationships with sex, size, cardiovascular variables and disease
The Veterinary Record, Vol 145, Issue 22, 625-629

The results of a questionnaire provided data about owners' perceptions of the cause of death of over 3000 British dogs. The mean age at death (all breeds, all causes) was 11 years one month, but in dogs dying of natural causes it was 12 years eight months. Only 8 per cent of dogs lived beyond 15, and 64 per cent of dogs died of disease or were euthanased as a result of disease. Nearly 16 per cent of deaths were attributed to cancer, twice as many as to heart disease. Neutered females lived longer than males or intact females, but among dogs dying of natural causes entire females lived slightly longer. In neutered males the importance of cancer as a cause of death was similar to heart disease. Mongrels lived longer than average but several breeds lived longer than mongrels, for example, Jack Russells, miniature poodles and whippets. There was no correlation between longevity and cardiovascular parameters (heart rate, systolic, diastolic, pulse and mean arterial pressure, or the combination of heart rate and pulse pressure) but smaller dogs had longer lifespans. The results also include breed differences in lifespan, susceptibility to cancer, road accidents and behavioural problems as a cause of euthanasia.


Overall, there are a ton of variables to be considered.

 

[Habibti]

Why can a flying squirrel that weights 60-75 grams live from 10-15 years in captivity but a similar size mouse can only live a few years?

They are different species. You're comparing apples and oranges.

 

[philomycus]

Why can a flying squirrel that weights 60-75 grams live from 10-15 years in captivity but a similar size mouse can only live a few years?

Same thing with Eastern Greys.

 

[bakaduin]

They are different species. You're comparing apples and oranges.

I may be mistaken but I think that was his point. Cats and dogs, like squirrels and mice, are different species and the ability of a cat to live into its 20s has no correlation to a dogs ability to live into its teens.

 

[Bill59]

In "the wild" (I put this in quotes because I personally dont believe that there is any wild for dogs.

wolves

 

[Habibti]

I may be mistaken but I think that was his point. Cats and dogs, like squirrels and mice, are different species and the ability of a cat to live into its 20s has no correlation to a dogs ability to live into its teens.

So the question is: Why do different species live different amounts of times? Aren't there a myriad of reasons? Do they live in different environments? Do they eat different things? Do they have different family/social situations? How far removed are they from one another evolutionarily (aka how huge are the genetic differences)?

According to this article (yes, wikipedia, so it may or may not be completely true), squirrels and mice evolved from one another millions of years ago.

Wouldn't this be a better question to ask of species that evolved from one another more recently (fewer genetic differences to consider)?

 

[akitavet]

wolves

Yeah dogs arent wolves. They are closely related, but they arent wolves. Even the most ancient breeds of dogs arent wolves. Dogs are dogs because they interact with humans. That was the driving force for their evolution. Raymond Coppinger says that dogs were never ever wolves, but instead that they evolved from a common ancestor who looked more like a coyote.

 

[Bill59]

Raymond Coppinger says that dogs were never ever wolves, but instead that they evolved from a common ancestor who looked more like a coyote.

Genetic analysis says otherwise. Canine genome studies and mitochondrial DNA analysis clearly show that domestic dogs originated from gray wolves.

A good review is:
http://www.genome.org/cgi/content/full/15/12/1706

 

[philomycus]

I may be mistaken but I think that was his point. Cats and dogs, like squirrels and mice, are different species and the ability of a cat to live into its 20s has no correlation to a dogs ability to live into its teens.

I think is point (and mine too) is that even though they are different species, you would think with their metabolism it would be similar.

Easter Grey squirrels can live into mid-teens in captivity, yet a rat that weighs about the same and may even have a slightly lower metabolism doesn't live as long.

 

[Kara31191]

I confused myself and others by comparing different species!

Thanks for the above resource. It's very interesting.

I just thought lifespan in general was an interesting topic to get into.

With dog breeds, is there anything that would prove mixed dogs having longer life spans?

I can't seem to find much on this info, but I'm sure the veterinary students and others have better resources.

 

[alliecat44]

, Epilepsy in Border Collies... These are catastrophic conditions that would dramatically effect lifespan...

Sorry, hate to hijack a thread to be really anal about something. But as a former head neurology tech, I'd just like to point out that epilepsy does NOT shorten a dog's life (unless they go into uncontrollable cluster seizures). i.e., nothing about the condition itself that kills 'em young.

(As a side note, it irritates the h*** out of me when I hear people say, "oh, my dog has seizures." "Seizures" is not a diagnosis. A seizure is a symptom, just like a cough is a symptom of a cold. Epilepsy is a diagnosis of exclusion. That is all.) *removes self from soapbox*



Carry on....

 

[akitavet]

The dog I had in mind when I wrote this is an 8 year old border collie. He had his first seizure at 4 years old and hasnt gone more than 6 weeks since without one. Usually he has 3-4 seizures and then 2-3 weeks off. Periodically, he has these episodes where he'll have 20 seizures in 48 hours or something like that. This dog will either go into status or he will obstruct for a 3rd time (phenobarb...makes him think everything is edible). He wont live to be 15 like the owner's last several border collie. He is the only surviving dog from his litter. All the others have been euthanized, and if he were my dog, I couldnt let him fry his brain like that and then have the stumbling, dazed quality of life he has in the good times. Its very sad

 

[alliecat44]

Border collies do tend to be more difficult to regulate than a lot of breeds, for whatever reason. And certainly some epileptics are more difficult than others, and each one has a "best" scenario (i.e., longest period of time between seizures that we can get + minimal drug side effects). And certainly some have such bad refractory epilepsy that quality of life is a big consideration.

I was speaking more from the point of view of clients who mistakenly think that a diagnosis of epilepsy is a death sentence.