There are three common and valued genetic conditions in dogs that result in stunted growth: pituitary (ateliotic) dwarfism which results in proportional minis, micromelic achondroplasia which results in shortened limbs, and brachycephalic achondroplasia which shortens the head.
All of these conditions are genetic disorders and all of them are definitive sine-qua-non features of some breeds, often in combination. These disorders aren’t accidental and unwanted, they are written into the breed standards. The breed wardens don’t want to breed these conditions out, they demand they breed true.
Mix and match your genetic dwarfism disorders.
Most of the toy breeds are ateliotic dwarfs: Chihuahuas, Boston Terriers, Italian Greyhounds, Maltese, Miniature Pinschers, Miniature Spaniels, Pomeranians, Toy Poodles, Yorkies, etc. This form of dwarfism is caused by a deficiency in somatropin which results in stunted growth of all somatic cells in the body. Ateliosis is a recessive allele.
If you’re a self-styled expert with a bad case of illusory superiority who has written more books than he’s read, you might say, “‘Achondroplasia’ literally means ‘an absence of good shape,'” but that’s not what the literal Greek means. “Chondro” is Greek for cartilage and “Plasia” means growth or change from the Greek word for moulding. Thus, the literal meaning of Achondroplasia is “Defective growth of cartilage” and that’s pretty much what it is. In general, it serves as the name for a cluster of similar disorders of the cartilage and bone (osteochondrodysplasias).
The most obvious effects of Achondroplasia occur in the long bones of the leg and “micromelic” means short limbs. Micromelic breeds include: Basset Hounds, Bulldogs, Corgis, Dachshunds, Lhasa Apsos, Scottish Terriers, Shetland Sheepdogs, etc. Micromelic Achondroplasia is a dominant allele with incomplete penetrance.
Another form of Achondroplasia that doesn’t lead to what we commonly consider to be dwarfism but which likewise results in insufficient growth of bone is Brachycephalic Achondroplasia which shortens bones in the skull. In dogs, shortening of the mid-face and maxilla and shortening of the lower jaw are inherited separately. Boxers have a shortened upper jaw, but their lower jaw is normal and they are normal sized in all other respects; whereas Boston Terriers have both upper and lower brachycephalism and are also ateliotic dwarfs, so they are proportional but small with smooshed faces.
Bulldogs have midface and upperjaw brachycephaly so their lower jaw juts out and they have trouble breathing, and they also have micromelic achondroplasia so their legs are short and bowed while their trunk is not significantly
Miniature Dachshunds carry both forms of body dwarfism, but their faces are unaffected.
And what do you get when you combine all three disorders? A Pug.
The most completely achondroplastic dog breeds are the toy imports of East Asia origin (bracycephalic + micromelic achondroplastic + ateliotic): the Pekingese, the Shih Tzu, and the Pug. The body-forms of these triply achondroplastic breeds represent the simultaneous superposition of all three varities of achondroplasia–micromelic, maxillary, and mandibular–on a midget frame. Thus, the Pug’s disproportionately stumpy legs, tending to bow (genu varum), result from micromelic achondroplasia. The Pug’s bulging forehead (frontal bossing); large, staring eyes (exophthalmos); pronounced stop (recessed nasion); and short midface (midface hypoplasia) all reflect maxillary achondroplasia. The Pug’s short lower jaw expresses mandibular achondroplasia. The Pug’s extraordinarily flat face and crowded dentition are accidence of the simultaneous operation of maxillary and mandibular achondroplasia.
– For the Love of Dachshunds, Robert Hutchinson
None of these disorders exist without other health complications like luxating patellas, arthritis, cataracts, and shortened lifespans. But, none of these disorders can be removed from breeds without fundamentally altering the breed itself. The Miniature Dachshund would simply be a Dachshund if you removed the pituitary dwarfism, but most of the other dogs no longer have a perfect corresponding wildtype breed.
For that reason, if the disease is to go, the breed is to go. I won’t count on that happening any time soon, if ever.
Diseased Dwarf Dog images provided courtesy of Cartoonize My Pet.
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Anton
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I suppose I wouldn’t be so biased against the dwarfed breeds if they didn’t do two things:
a) Breed for the obviously major dysfunctions.
Once you see a dog that can’t walk, only waddle or a dog that can’t breathe – it’s hard to imagine how these are “desirable traits”.
b) Breed so selectively for certain traits like “teacup size” dogs that you are certain to hear the phrase “normal for the breed” for various problems that are practically unheard of in other breeds.
I’m beginning to think “normal for the breed” is one of the most terrifying phrases one can hear. It implies that what would otherwise be a “known problem” that ethical breeders try to minimize in their animals has become accepted as “normal”.
Very interesting info. I own Pomeranians which seem to be similar to the Dachshund example. If they “grow” larger, they are then considered to be Klein or Mittelspitz. In FCI countries, it is one breed with various divisions i.e, Zwergspitz (Poms) Kleinspitz (what we call “Victorian” Poms), Mittelspitz, Wolfspitz (keeshonds) and Giant Spitz.
I had also read that there was a genetic cause for small size in some cases, which did not include a defect in somatropin (otherwise known as Growth hormone)
There is a widespread defect in Pomeranians called “Alopecia X” which is, curiously enough, also a defect that may be associated with growth hormone deficiency and dwarfism. However, Growth hormone administration has not proven helpful for this condition. There is a search currently for the cause of alopecia X in Pomeranians. It is presumed to be a genetic defect. Time will tell, I suppose.
Thanks for the info Geneva. So far, the book I link to in this post is the only good source I have on “ateliotic dwarfism” … so far it’s a very nebulous condition. One might say that it can simply be bred down to. Others might say it’s a disorder or disease. I am satisfied in saying that it’s really up in the air but it’s better to err on the side of appreciating that there might be negative side effects and while it might not be a simple single gene “disease” … we should, as you suggest, keep an eye on it. This might be a tandem repeat situation where we can get very fine gradients in phenotype, or it might be different alleles of a single gene locus.
The toys are well established and some are ancient. They’ll get by with pituitary dwarfism as they have, but the more we know about it the more we can prevent the real issues like when they start combining really really short noses and cork tails… I mean, the Pug is a mess.
when your adverts for show puppies make people throw up you really need to rethink your breeding program http://forums.moneysavingexpert.com/showthread.php?p=51712631
maybe instead of vets and judges at crufts we should ask a random member on the non dog owning public their opinions.
Odd-looking puppies. But I’ve never seen an English Toy spaniel at that age (or King Charles spaniel, which is the UK name).
I agree with the second response on that thread: why is the breeder advertising on a site for rehoming dogs, and why are the puppies shy? That’s more bothersome than the odd-shaped heads (then again, as a collie person my perception of “odd-shaped heads” is probably a little skewed).
I’m a little curious: how short can a dog’s snout or legs be without being dwarfed? And is it possible to breed toy-sized dogs without dwarfism coming into play?
Yes. IGs, Minpins, Papillons, Toy Manchester terriers, Toy Rat terriers, none of these are dwarfed dogs.
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It’s my understanding that those dogs would be considered pituitary dwarfs.
The pituitary is the gland that produces several main growth hormones and there are ostensibly two ways you can use this to alter the same of dogs, one being natural variation in pituitary production and the other being diseases such as tumors that effect the pituitary in radical ways.
It is likely that if you breed for small dogs over many generations you will find that you have selected for reduced pituitary output.
In some breeds we see radical inherited pituitary dysfunction that results in dwarf dogs that are not likely to survive for very long (i.e. GSDs).
Pituitary selected dwarf dogs are more likely to be proportional and to my knowledge they are not known to have the same degree of associated problems (but they are not free from problems, there are issues with being small!).
Yes I know something about the Pituitary gland as i have a growth on mine & it affects things like sexual maturity, hormounes & that in it’s self can lead to a host of secondary symtoms. It also has a lot to do with height, I’m taller than the magority of females but it can go the other way & make you to short too it depends on how the gland is affected.
I’m not sure where you get that Shelties are micromelic? Coat length sometimes makes it LOOK that way, but if you put hands on the dogs (or wet them down) they tend to be nearly square (back just a little longer than legs) and quite proportional. There was a fashion some years ago for what many of us derisively called “shorgis” (longer-backed, shorter legged dogs), some of which MAY have been micromelic, but you don’t see that in either the show or performance dogs now.
The show dogs’ legs are heavily chalked and fluffed to make it look like they have “lots of bone” (despite a standard that calls for moderation) but in general, in an unfluffed state they are very moderate. Most of the Shelties I see who REALLY have “lots of bone” are also oversized by breed standard.
The source is linked in the article:
For The Love of Dachshunds, by Robert Hutchinson
The link is to the book on google.com. I searched within the book, and there is no mention of Shetland Sheepdogs and micromelic (though there are references to other dwarfed and micromelic breeds).
Are you sure, that pug has an ateliotic dwarfism? How it can be noticed if it’s brachycephalia is so serve, that it masks all visible signs of A. dwarfism?
Just wanted to mention that bulldogs are not micromelic. They have normal shaped, untwisted limbs. They may look twisted because of the bench front which puts them out at the elbows, but the limbs are straight. Pugs also have normal limbs.
Interesting read thanks.
I keep JRT’s, little dogs as most terriers are. This is a type of dog rather than a strict breed (in mine and working or many cases outside of showing) but you do see two of the types mentioned here definitely and all manner of combinations thereof just not the Brachycephalic dwarfs. This is probably because there are bits of everything in them besides bulldog.
I prefer the muscled up Ateliotic ones [blush]. Lets hope that being little they don’t need too much of that pituitary’s hormones.
I like the little ones but not the extreme little ones on stumps, not too fine not too anything, plenty of muscling but petite head, petite straight short limbs and tail. All approximately give or take.
These live for a very long time mine I had as child lived to 16 and my parents ones even longer with no health problems at all. Most of their minor problems requiring a rare visit to the vet were self afflicted during the charming mad frenzy with which they live life.
However on another blog the “terrierman” I was reading where he sharply criticises “dwarfism” in the JRT or the shorter variety. Extolling in a rather partial way the virtues of the longer legged types instead. Claiming they weren’t dwarves and boasting they could fit through a plug hole where a fox presumably lives.
Now that I understand all JRT’s are dwarfs of some form or other, I feel he could have been a little less ornery and smug about his minis on stilts.
Could all domestic dogs have some form of hormone disruption or other simply by having been selected away from the wild form? Down, up, sideways,forward, backwards and etc because none are exactly the shape and proportion of a wild grey wolf now are they? Pure working or pet?
“most of the other dogs no longer have a perfect corresponding wildtype breed.”
It wouldn’t need to be perfect, though would it? The golden jackal has 78 chromosomes arranged in 39 pairs same as the wolf so can produce fertile off spring with each other and the domestic dog.
There are a number of sub-species of golden jackal one considered truly dwarf Canis aureus riparius or Abyssinian jackal it only stands approx 12-inches high, about an average jack russell in height. Compared to the approx 92-inches of the Siberian wolf. Twelve inches is only three inches away from a mini dachshund.
Golden jackal dog hybrids “are small, agile, trainable and have an excellent sense of smell” “Twenty-five jackal-dog hybrids are used by Aeroflot at Sheremetyevo International Airport in Moscow for functions including bomb-sniffing. Their breeding program dates back to 1975, but it was not applied to bomb detection until 2002.”
There’s always hope, but you could technically I imagine at least reinvent some little dogs which would look very similar maybe even minus any dwarfing “disease” ?
Wildtype, not wild. The “wildetype” allele is the typical allele present in the population. Basically the “normal” or “default” or most popular allele against which we identify the novel “mutant” allele.
My point is that there is no non-dwarf Corgi. There is no breed that is 99% the same as the corgi save the dwarfism. So if you wanted to remove just that allele and produce a Corgi without dwarfism, you’ll need to outcross to another breed that doesn’t have dwarfism, but you’re also breeding against all the OTHER characteristics that are not in common with the breed you’re breeding to.
So all non-dwarf breeds are basically “wildtype” in that respect compared to dwarfism. We don’t need to return to “wild” wolves or coyotes or jackals. Although they are also “wildtype” in that concern, save the few that have been documented with various forms of dwarfism.
If we wanted a perfect Corgi without dwarfism, we’d have to do something much like the Bobtail Boxer back-cross program except bringing in the “normal” size allele and then breeding out anything else we brought in over several generations. We could do this with just dogs.
We could also, at great expense, use gene-therapy to introduce the normal size gene into an otherwise 100% Corgi.
Most Corgis are healthy and long lived – dwarfism aside. And they breed and free-whelp naturally. I wont keep a dog in my program who needs to have C-secton after C-section or who isnt willing to accept a male.
Balanced Cardigan corgis are sound and solid workers and pets. My mutts do agility and herd and run and walk and one is my service dog. Corgis are dwarfs – it makes them corgis. In welsh it means “dwarf dog”. Without the dwarfism Corgis would be 16inch tall (around that – like mini aussie size i gather).
Knock on wood the Cardigan breed as a whole is a lot hardier than most purebred. It is quite common for the dogs to live long into their teens.
Yes it is interesting that many small dogs do live long healthy lives even carrying the genes for some of the varying forms of dwarfism without any of the what we could expect health complications. This aside from badly inbred pedigree dogs or show dogs or extremes.
Maybe being small has its advantages, it certainly has in the wild in many conditions and there are dwarf/tiny forms of many species from parrots to cats to horses and here wolves.
Small dogs just live longer and the less inbred and functional the longest.
On the other hand dogs with gigantism or large breeds don’t fare nearly as well often dying young cripple messes. There are too of course many giant forms of wild animals who fare much better having millions of years of evolution to finely tune function and health. Every part finely honed for being huge even extremely so.
I have to sign off we have a thunder storm and the plugs are shooting sparks….sure the house is not earthed properly
Was the “Mini Aussie” cattle dog a product of amongst other breeds corgis ?
Mini Aussies are smaller australian shepherds. Depending on who you ask….the ones I met are smaller sized Aussies. Some mix shelties and other breeds in. AKC calls “mini american” shepherds (cause the Aussie people crapped themselves over the Mini Aussie name).
Mini Aussies are not my breed but they are around 14-16 inches tall. No Corgi was used as far as my knowledge
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“There are miniature and toy versions of “standard”-size breeds, but this is not the same as dwarfism, the latter being the result of an abnormality (disease?) rather than a variation within normal limits in genes. People are always developing miniaturised strains by selectively breeding small examples to each other, and continuing to select until “regular” size individuals no longer appear. Some years ago, the heiress to a margarine fortune started to develop miniature Borzois. While some detractors accused her of using Whippets to jump-start the reduction in size, it really doesn’t matter much. Livestock breeders know that you can introduce a gene for some dominant characteristic such as colour, but then keep breeding the other structural phenotypes back into in the original breed in such a way that the “new breed” (really a minor variation on the one they started with) will look and perform no differently, except for that colour. Or whatever trait they want to introduce.”
Fred Lanting: A Small Problem. Dwarfism in Dogs, part three: Confusion Continues. 2005 http://www.dogstuff.info/dwarfism_part_three_lanting.html
So it does continue.
Is this the same thing as you describe with the corgi example, introduce a “wildtype” surrogate, boxer then simply breed down back to a corgi size wouldn’t you have to keep introducing the “defective” dwarf corgi genes.
The dogs bred in the piece above like the mini Borzoi would never have a pituitary problem at start or finish as its simply “a variation within normal limits in genes”? Like a whippet maybe? Or is this not true?
So you could breed mini JRTs which are in fact not dwarves at all? Simply by breeding down a longer legged parsons for example? Maybe like the Australian JRT show number.
Is using a dwarf just a short cut to small, like using a Parsons on a Dachshund. Is a Parsons free of dwarfism itself? Being possibly “a variation within normal limits of genes” shrunken fox hound or some such “wildtype” thing?
Sorry about all the questions Im asking myself these things, though. The JRT is such a variable type anyway Im sure almost everything mentioned plays a part in the incredibly athletic dwarf JRT.
It looks like a mini BC, is it a working dog? Used to herd ducks or something?
Im a bit behind in all these breeds I just learnt what a Chinook was. Not something I suppose in much use these days.
Christopher clearly knows nothing about Italian Greyhounds! This breed does not have short legs. The bones are entirely normal. In fact they are rather long legged.This is not a breed with dwarfism of any type. It is a small Sighthound. At one stage 100 plus years ago,they were crossed with Chihuahuas which was a disaster and no doubt some ended up with dwarfism but this was not the breed!
The problem, Jo, is with your lack of understanding of Ateliosis, or proportional dwarfism. Italian Greyhounds are SMALL sight-hounds, and that small bit is directly from their dwarfism. They are long legged only in proportion to their other body measurements, their legs are not objectively LONG. But apparently you are failing to comprehend this, most likely because you have failed to appreciate that achondroplasia is not the only dwarf condition.
The problem, Christopher, is that there is nearly as much or more variation in Italian Greyhounds size-wise as there is in Shelties (which I know are also argued as dwarfs in this post, but no part of the book you refer to talks about them, at least that I can find). IGs may in fact be ateliotic dwarfs (and it would be interesting to hear if there is any way to test for that and if it HAS been tested) but I’ve seen purebreds as tall as whippets, and there don’t seem to be a lot of them that are smaller than about 13 inches at the shoulder.
That said, at what point would you decide a small Border Collie was a dwarf, or are they all just small Border Collies? BCs under 18 inches have been pretty common, but we’ve been seeing BCs under 16 inches more often too, and I wouldn’t be surprised if SOMEONE out there is aiming at 14 inches. This is an honest question–I am not trying to be a jerk here.
Or let me put it this way. At what size is an individual dog a dwarf versus a small dog? Is a 17-inch Italian Greyhound a dwarf? Is his 13 3/4 inch sister? What about my 16.5 inch Sheltie, or his 17 3/4 inch son, or his 13.5 inch daughter? Are Jack Rusell terriers ateliotic dwarfs with their “Puddin'” versions achandroplastic, or are the puddin’ dogs both achandroplastic and ateliotic as your cited source argues about miniature Dachshunds? Is a 16-inch Border Collie a dwarf? What about Cocker Spaniels?
Christoper find this incomplete development;associated with dwarfism that is associated with anterior pituitary deficiencies phenotype with normal intelligence and proportions likely problematic for most in these breeds of reduce size from foundation.
Such as achondroplasia an autosomal dominant genetic disorder, which apparently means .. health problems from their disorder compared to other species that exhibit dwarfism. Premature arthritisis the most common affliction associated with this phenotype. is noted in greyhounds, Maltese, Miniature pinschers, Miniature spaniels, Pomeranians, toy …
I believe many just do not realize how large the foundation of their breed and how selective breeding affected the current status of bone development.
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I think the Basset Hound is a fascinating dog. It looks exactly like a fox hound on short thick legs, its body retaining the proportions of the full size dog its legs not.
Apparently this is useful! And apparently not a health issue at all at least not in the large packs of working Bassets in France. Though how they ever catch rabbit Im not sure? I thought you needed a courser type dog.
Anyway when the type got to Britain and the show bench it was changed by selecting away from a functional hunting dwarf hound to a fixed standard and with much line breeding became the very sorry exaggerated mess it is today.
The same story for the pug used in this blog entry. That is it came from China looking rather functional as a pet. This is the story of many breeds that found them selves in the West whether it be the UK the USA , Holland et cetera but primarily the USA and the UK.
But does this mean that the Pug had all those converging forms of dwarfism even then, all along, and was pretty much functional with them for thousands of years?
. Even though I have a soft spot for black pugs and our family seems to have had them as house dogs for many generations Im not looking for an excuse to get one. This is one tradition Im willing to forgo. Im not looking to have a vet in permanent employ, city vets seem to be a menace at the best of times ((:).
Christopher as usual might make some uncomfortable with his Truths, but ignorance folks is not bliss. I found the following information in researching the topic. It was found in research studies only six or seven location in dog genome are necessary to explain 80 percent of differences in height and weight among dog breeds. Dwarfism is a condition in which the growth of the individual is very slow or … Dwarfismcan also result from a lack of somatomedin C (also called insulin like growth factor, IGF-1) production. … Most of the genes in the two chromosomes of each pair are identical …. …. The condition is seen in dogs, cats,mini- mice…..
Studies of this growth factor IGF began with researchers exploring the genetic basis for size variation among dogs by comparing the DNA of various small dog breeds, including Chihuahuas, Toy Fox Terriers and Pomeranians, to an array of larger dog breeds, including Irish Wolfhounds, Saint Bernards and Great Danes. This investigation study found that variation in one gene — IGF-1, which codes for a protein hormone called insulin-like growth factor 1, is associated with small stature across all dog breeds studied. If researchers want to make a giant chihuahua, they now know where to start.
http://www.nature.com/news/2006/061009/full/news061009-12.html
I believe it is quite normal for initial reaction to the bitter truth to be in a short term of denial. But selective breeding and Breed Standards should be reconsidered in my opinion with the scientific facts of health issues related.
http://www.ncbi.nlm.nih.gov/pubmed/22903739
http://www.sciencedirect.com/science/article/pii/S1063458405800251
http://circres.ahajournals.org/content/97/5/411.full
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC300772/
I find the whole thing very confusing. When I took Island biogeography (decades back), the understanding was that dwarfism of some sort appears in many island populations (and some Middle Eastern wolf populations). This was usually interpreted as an adaptation to reduced resources and less intense pressure to grow large.
Short legs appear in many species (eg, most weasels) with no apparent ill effects on health. So biomechanics doesn’t rule out short legs.
To further confound the subject, smaller breeds of dogs generally have longer life expectancies than larger breeds.
With dogs, the thing that DOES seem to be clear, is that giantism is strongly associated with musculoskeletal problems and short lifespans.
Yes. This not to refute anything said in Chris’s blog post above but….(:
Interestingly enough true pituitary dwarfism in dogs like the GSD doesn’t seem to be the same kind as in any of the breeds in the “chart” in this blog. Even though it’s also caused by pituitary problems.
When it appears in GSD puppies they are born a normal size puppy but don’t thrive and the mini version doesn’t live very long plus all its hair falls out unless it’s continuously treated with hormone.
This is completely different to how proportional dwarfism manifests itself in for example the mini Pincher which doesn’t have all these side affects and early death as a result? The GSD dwarf is also a proportional type mini.
The Dwarf Abyssinian Jackal has now been reclassified as a wolf sub species, the smallest of course at only 11 inches at the shoulder.
I think it’s right to make a distinction between a profound dwarfism allele like the one we see in GSDs that could rightly be called a disease gene or a single gene trait versus the sort of general “we bred them down from larger dogs to smaller dogs but they’re still mostly proportional and it took 10 generations of breeding” sort of pituitary shrinking we see in some other breeds.
I think that might be the cause of concern why some other comments seem to think that their dog isn’t a dwarf because it’s not necessarily like the achondroplasia gene or something that is a single profound mutation, at least in all cases.
From what I understand there ARE pituitary focused mutations that greatly limit the size of the animal compared to its parents, proportional dwarfism, but that this may or may not be the case with a variety of ateliotic dwarf dogs, whereas some are clearly a combination of multiple genes of smaller effect working together to just trim down the dog. I imagine that the symptomatic disease profile is different between these various causes too, where some non-standard pituitary mutations cause animals that don’t have full life spans whereas others don’t appear to harm longevity.
The GSD puppy version appears to be more profound and a singular mutation and not sustainable as something you could build a toy GSD breed around due to the eventual lethality.
Yes.
And of course the “mini” wolf is technically sustainable (if it wasn’t so threatened with extinction) because it was shrunk in the process of thousands (millions even maybe?) of years of evolving into that mini sub-species of wolf. But it could’ve also of course been down to just one gene mutation?
I wonder if this malleability of the wolf/jackal isn’t why we can have so many vastly different size dog breeds. To Kathy’s interesting point…… that is might the mini wolf (assuming the now formerly named Canis aureus riparius) also be a successful variation of a single gene in the wolf the IGF-1 gene or not?
Or does this work in a completely different and varied way?
Dwarf mongoose, what can I say I absolutely love them! I also love tiny bat species birds and of course the African elephant and Martial Eagle. So liking big and small dogs is not that much of stretch.
I can’t imagine life without little dogs and big dogs in fact (:
Hello, Christopher… I have enjoyed viewing your site. I have a 13 year old female Border Collie with short legs (like those of a Corgi). I’ve had “Piper” since she was two years old. A friend of mine brought her home from the veterinary clinic where she worked. Someone brought her in and knew very little about her history, other than her mother was definitely a Border Collie. One look at Piper and there is no doubt about that, until she stands up.
I’m tired of people asking me “what is she mixed with?” I have no idea whether was sired by a wandering salesman (unlikely to have been a Corgi on the loose…) or if she is a “dwarf” born among a litter of pedigree Border Collies. She’s a beautiful dog, a Good Dog with a capital “G”. I believe she is fully a Border Collie, because she looks like one and she acts like one – she has been known to try to “herd” bunnies in the back yard… lol… taking the typical Border Collie stance, but she never acts aggressive toward them – just wants them to be all together. She does not believe it when I tell her she cannot corral bunnies…. Thanks for your website, I will certainly pass the URL on to other Border Collie enthusiasts!
I’ve seen quite a few dwarf BCs types, think it is a cross with a corgi when you get the short legs and normal body proportions. It could be a Cardigan Corgi cross if it’s not 100% dwarf BC.
I saw a clipped Corgi for the first time last week and I couldn’t believe how long the body was in fact. It appears much longer than even a dachshund, it’s not really long but compared to the leg it appears so.
Why do you get tired of people asking what your dog is crossed with? I would take that as a compliment. I often wonder this when I see a particularly fine looking cross.
Is there any possible way to breed back from the dwarfism? I wanted to try but seeing all the mix breeds I am afraid of making more dysfunctional dogs, but I don’t want to throw away those breed lines either.
Cynthia dwarfism is a mutation that is linked in many Breed Standards. These highly valued disorders resulted in stunted growth.due to pituitary disfunction.They were created by Inbreeding in homozygosity, that the chances of offspring being affected by recessive or these deleterious traits increased over decades of such breedings that developed Show Dog Breed Standards that rewards. This generally leads to a decreased biological fitness or inbreeding depression which affect ability to survive and reproduce. it cannot adapt and, most importantly, reproduce. … has been high juvenile mortality, low fecundity, and poor breeding success.The avoidance of expression of such deleterious recessive alleles caused by inbreeding, is selective reasoning. Crossbreeding between populations can have positive effects on fitness-related traits. “Sequence analysis of mtDNA from ancient dogs and wolves reveals haplotypes that are not present in modern populations of either, indicating a loss of diversity in both species since the division. You bet take a good look at what this Albany Breeder has done for the Bassett Hound.http://pedigreedogsexposed.blogspot.com/2011/03/basset-hounds-eye-on-future.html
The Master Breeder is a great article regardless of your breed to begin any breeding protocol changes. http://www.topsfieldbassets.com/breederstoolbox/making_of_a_master_breeder.htm
https://dogbehaviorscience.wordpress.com/2012/09/29/100-years-of-breed-improvement/
chihuahuas aren’t pituitary dwarfs. this type of dwarfism isn’t part of any breed standard because it has extreme side effects like underdeveloped kidneys and liver (often leading to failure of those organs) and cardiovascular problems, and drastically decreased lifespan (average ~4 years) which doesn’t apply as small breeds are often very long lived. also complete baldness when the dog hits puberty, which would be the most obvious sign, which chihuahas and other small breeds don’t express.
small body size isn’t necessarily the result of a single or several dwarf genes, as body size is a polygenic trait which makes it very variable, even without the presence of faulty dwarf genes that have negative impact on other parts of the anatomy besides growth