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Thread: What dog breed?

  1. #21

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    Quote Originally Posted by Hyacinth View Post
    Mosh

    That's not very consistent.

    There is a possiblity that your shelter mutt puppy has been rescued from a puppy farm. There's no guarantee of genetic diversity in a shelter puppy either.
    No guarantee, but like I said a crossbreed is far less likely to have genetic problems for the reasons outlined above. Besides once you start inbreeding mutts, they aren't really mutts but just a new type of purebred.

  2. #22
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    a crossbreed is far less likely to have genetic problems for the reasons outlined above
    So a dog from a random mating with no genetic testing or natural selection in its ancestry - is less likely to have genetic problems than one from a breeder that does do the testing and selects to reduce genetic faults?

    Genetic faults are part of genetic diversity - so breeding to reduce them and focus on desirable traits - can be a good thing. I don't think you have any basis for assuming a shelter puppy would have less genetic problems than a puppy from someone who is doing their best with the technology we have - to avoid genetic problems.

    wikipedia - is hardly a reliable source and prone to bias from people with a persistant vested interest - eg puppy farmers and pet shops.

    Britannia - good source - theoretically - if the article you picked was relevant to dogs from shelters and pedigree dog breeders. Their source is the dog breed info link - which seems to be even less reliable. It seems to be more about selling designer mutts - which you agree with me - is not a great way to get a healthy puppy.

    the plant cell link - defines the word but does nothing to back up your theory that shelter puppies would fit the definition - how do you know you're getting a product of a diverse genetic cross?

    And how do you know that product is not going to have expressions of genes you don't want. They say the offspring often have more vigor... but they don't say it's the majority of a crop. And there would be some crosses - that could easily produce a majority failure.

    So I would like to see the study that shows that shelter dogs (or puppy farm dogs sold as having "hybrid vigor" live longer than pedigree dogs (whose ancesters have been chosen to reduce expensive and life threatening genetic faults) with fewer genetic related health problems.

    Wiki has a bit. Not my fave source... their article shows pedigrees beating mutts by a few months.
    Aging in dogs - Wikipedia, the free encyclopedia
    Accidents aside, life expectancy usually varies within a range. For example, a Beagle (average life expectancy 13.3 years) usually lives to around 12–15 years, and a Scottish Terrier (average life expectancy 12 years) usually lives to around 10–16 years.

    The two longest living dogs on record, "Bluey" and "Chilla", were Australian Cattle Dogs.[7] This has prompted a study of the longevity of the Australian Cattle Dog to examine if the breed might have exceptional longevity. The 100-dog survey yielded a mean longevity of 13.41 years with a standard deviation of 2.36 years.[8] The study concluded that while Australian Cattle Dogs are a healthy breed and do live on average almost a year longer than most dogs of other breeds in the same weight class, record ages such as Bluey's or Chilla's should be regarded as uncharacteristic exceptions rather than as indicators of common exceptional longevity for the entire breed.[8]

    A random-bred dog (also known as a mongrel or a mutt) has an average life expectancy of 13.2 years in the Western world.
    This is a bit more interesting.
    Perception v Reality
    they also have a result that shows mutts on average live a year longer than pedigrees - but that contradicts whats in the wiki data...
    And the specific data is a bit old - so the mutt breeding may have been less deliberate and more by dogs own selection (and there's some evidence around to suggest that an animal that has its choice of mates - will choose the one that increases the genetic diversity of the puppies. And that's how you get huge fence jumpers with home dogs and big dogs mating with tiny dogs. Not that the tiny dog would always survive the birthing. Sample sizes are also a bit small - which also means the data is less reliable.

    So with a shelter puppy - you don't know what you're getting. With a pedigree - where you can meet the parents, see the test results, you have a bit more chance of knowing what you're in for.

    Pedigree Dogs Exposed - The Blog: Hybrid vigour... fact or fiction?
    “You can get hybrid vigour when crossing two separate 'types' which have been kept pure in their own gene pools for some time. The theory is that over time, 'inbreeding depression' sets in with any closely-bred/line-bred strain, which is immediately lost when crossed to a different strain.” This is exactly right.

    But she then added: “Of course if you cross two breeds that get epilepsy, or two breeds prone to hip dysplasia, or PRA (progressive retinal atrophy) - all you're going to get is epilepsy, HD or PRA. No amount of hybrid vigour can wipe away recessives present on both sides.”
    and
    “The claims about crossbreeds being healthier than pedigrees are based on unproved statistics” wrote one poster and no one chipped in to point out that they were wrong.
    There's another bit about insurance companies having cheaper premiums for mutts, because they don't have to pay out as much. But it may also be true that pedigrees are just more likely to be insured.

    So - if your mutt's parents chose each other with no human help... then the hybrid vigor argument has a good chance of applying. But if it's a designer mutt - the opposite could well be true. And there's not enough reliable data out there to say one way or the other.

  3. #23
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    A cavie? for a 11 yr old that wants a puppy.

    Not sure what sorta kids you got Beau, but mine would not be happy if i tried to sneak this past quality control of a pubescent poppit.
    lol, hang on, are we talking a guinea pig or a dog here, is cavie a CK Charles? lol

  4. #24

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    Quote Originally Posted by Hyacinth View Post
    So a dog from a random mating with no genetic testing or natural selection in its ancestry - is less likely to have genetic problems than one from a breeder that does do the testing and selects to reduce genetic faults?
    Absolutely, as long as that dog has a diverse gene pool. Like I said if a mutt is a 3rd generation inbred it will have huge problems. If it is a 1st generation it will be a carrier for the recessive conditions of its parents but it will usually not display those conditions itself.

    If you breed two dogs from opposite sides of the country together, and then keep doing that with each subsquent generation, the result will be vastly superior to any purebred because the recessive alleles have much less of a chance to match up and display themselves in any offspring. Obviously this isn't feasible but it gives you an idea of what I'm talking about.

    Quote Originally Posted by Hyacinth View Post
    Genetic faults are part of genetic diversity - so breeding to reduce them and focus on desirable traits - can be a good thing. I don't think you have any basis for assuming a shelter puppy would have less genetic problems than a puppy from someone who is doing their best with the technology we have - to avoid genetic problems.
    Doing their best, but as long as you breed for appearance you're going to breed in genetic problems as well, it's unavoidable. Most purebreeders have puppies that have to be culled from every litter. A large proportion of purebred dogs will be carriers for whatever recessive conditions are running in their breed, and many genetic problems, such as hip displaysia, don't display themselves until the dog is much older. If a breeder is breeding for appearance, they can't avoid genetic problems unless they DNA test every dog. At best they are preserving recessive conditions by making their dogs carriers of the condition with only one allele. At worst they are producing puppies with both alleles which they will either sell or cull. It's not enough to look at a dog and observe whether or not it has a condition, because that does not address whether it is a carrier and possesses the recessive allele in its non-active state. The ONLY way to make sure recessive conditions display themselves with less frequency (aside from performing an expensive DNA test on every dog) is to increase the size of the gene pool. It's like a lottery, only you're trying not to win.

    Sometimes people even deliberately breed problems into their dogs in the name of a breed standard appearance, as in the case of the pug, French bulldog, and boston terrier. These dogs are bred for a flat palette and a shallow nasal cavity which causes breathing problems. The breed standard is so extreme that the dog's quality of life is reduced. People love it because it's "cute", but the differences between these dogs and what the breeds looked like 100 years ago is shocking.

    The statistics that crossbreeds are superior to pedigrees are far from unproven, it's just that people on the internet don't bother to look at the sources for encyclopedia articles. You usually have to do a lot of reading.

    http://web.archive.org/web/200903270...s/Mcgreevy.pdf


    Quote Originally Posted by Hyacinth View Post
    wikipedia - is hardly a reliable source and prone to bias from people with a persistant vested interest - eg puppy farmers and pet shops.
    The purebreeding industry also has a vested interest in making people think that pure bloodlines are a beneficial thing. It is a multi-billion dollar industry with backers like Crufts, the Kennel Club of America, and the Royal Kennel Club. Wikipedia shows all its citations, which are legitimate and are referenced in the Harvard style.

    A. Egenvall, B.N. Bonnett, P. Olson, Å. Hedhammar,Gender, age, breed and distribution of morbidity and mortality in insured dogs in Sweden during 1995 and 1996, The Veterinary Record, 29/4/2000, p. 519-57
    B.N. Bonnett, A. Egenvall, P. Olson, Å. Hedhammar, Mortality in Swedish dogs: rates and causes of death in various breeds, The Veterinary Record, 12/7/1997, S. 40 - 44) “Mongrels were consistently in the low risk category” (S. 41)
    H.F. Proschofsky et al, Mortality of purebred and mixed breed dogs in Denmark, Preventive Veterinary Medicine, 2003, 58, 53-74 "Higher average longevity of mixed breed dogs (grouped together). Age at death mixed breeds (Q1 Q2 Q3 mixed breeds 8,11,13, purebreds 6, 10, 12)"
    A. R. Michell, Longevity of British breeds of dog and its relationship with sex, size, cardiovascular variables and disease, Vet. Rec., 27 Nov. 1999, S. 625-629 "There was a significant correlation between body weight and longevity. Crossbreeds lived longer than average but several pure breeds lived longer than cross breeds, notably Jack Russell, miniature poodles and whippets" (S. 627 - thus only small and toy breeds, as to be expected)

    Quote Originally Posted by Hyacinth View Post
    So - if your mutt's parents chose each other with no human help... then the hybrid vigor argument has a good chance of applying. But if it's a designer mutt - the opposite could well be true. And there's not enough reliable data out there to say one way or the other.
    Hybrid vigor does not apply to designer mutts because they are inbred. If you take two mutts who are carriers of their parents genetic faults and breed them with their siblings or cousins, those genetic faults will display themselves once again, because they are recessive. If you take a crossbreed that is a carrier of a recessive condition and breed it with a dog that is not, the offspring will have 50% less chance of being carriers.

  5. #25

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    Without going into all the TLDR posts, I would applaud the OP for considering a purebred, based on the importance of predictability when buying pets for younger people.

    Cavaliers are lovely pets for young people. Depending on what you like you might also consider a Tibetan Spaniel.

    And briefly but importantly - no, anything crossed with a whippet is not necessarily great. In fact many rescue dogs that are whippet crosses are hunting-bred and can be unpredictable. Be wary of generalisations. And yes, internet references can be dubious. Just 'cause the internet says so, doesn't mean it's the truth...

    All those arguments posted above have two or more sides, and each side will have numerous sources to back up their various versions. Credibility is the key.

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