MERLES AND GENETICS
MERLES – For those who are not familiar with the merle gene, one fact is indisputable: In order for a dog to BE a merle, it MUST HAVE one merle parent, either sire or dam. This gene cannot remain ‘hidden’ for generations, like chocolate or blue, which are recessive colors, thus proving that it has only recently been introduced into our breed.
A merle dog (Mm genetically) contributes one of these genes when bred, either M (merle) or m (non-merle). If a puppy receives the M (merle) gene, it will be merle. If it receives the m gene, it will not be merle. The M (merle) gene acts on whatever coat color the puppy has.
The problem with allowing the (new) merle color in Chihuahuas, is that we have so many light-colored dogs. Breeding these light dogs to merle will result in fawn, cream, red, sable, white, etc. merles, which are often NOT recognizable as merles as adults(though when bred to black tris, they will produce blue merles, thus identifying one parent as a hidden merle). When these hidden merles are bred to other merles (accidentally or unknowingly), thus doubling up on the merle (M) gene, the result (if the puppy inherits one M–merle–gene from each parent) will be a puppy with two M genes–a homozygous merle. These puppies will be deaf and/or blind, and some will have other internal health problems as well as possibly being infertile. The fact that they are deaf and/or blind will not be recognized until they are older (around weaning time), hence a decision will have to be made about what to do with them….
At this time, there are already normal (single M) merle Chihuahuas which have been diagnosed by two independent veterinarians with deafness and eye problems that will lead to blindness. Is this really for the betterment of the breed?
What the Merle Breeders do NOT tell You
Another much more serious and important issue is the higher occurrence of health problems in Merle Chihuahuas. You may wonder how this is so, when merle is only a color pattern? Well, unfortunately, unlike other colors, the merle gene acts on a color and lightens and whitens certain parts of it (creating patches)…the whitening is what causes defects. Often, when a dog’s coat is whitened, the pigment inside of their ear and on their eye, also whitens…making the dog DEAF and BLIND as the nerves endings atrophy and die.
“Health Problems Associated with the Merle Allele – Both heterozygous merle (Mm) and homozygous double merle (MM) dogs may exhibit auditory and ophthalmic abnormalities including mild to severe deafness, increased intra ocular pressure, ametropia, microphthalmia and colobomas. The double merle genotype may also be associated with abnormalities of skeletal, cardiac and reproductive systems.”
Definition of Heterozygous-one parent is a merle, the other is a non-merle. Also known as single merles, or Mm.
Definition of Homozygous-both parents are merle. Also known as double merles, or MM.
Based on information about the merle gene in Dachshunds, all merles that are brought into the world have a 36.8% chance of developing some sort of hearing loss, resulting from either slight hardness of hearing to total deafness (Willis). This percent is for puppies that result from one parent that is a merle, and the other that is a non-merle. Other problems such as eye problems were also apparent. While many breeder’s admit that there are problems when breeding two merles together, they do not admit there is also a problem when breeding a merle to a non-merle which is the breeding most breeders do. This is what the Merle Chihuahua breeders DO NOT tell you. You can still get deaf and blind puppies from this type of “safe” breeding.
So please keep in mind, if you are interested in getting a Merle Chihuahua, you may not actually get a healthy puppy. A pup may appear to be healthy, but might actually have impaired hearing or vision. For the reason of health problems and questionable parentage, the presence of the merle pattern in Chihuahuas is being banned in many countries world-wide.
What every judge must know about Chihuahuas in order to understand and judge them correctly. Why must a Chihuahua move quickly? and constantly! Why is he programmed to fear overhead movement and why does he “pancake”?
1. WHAT IS THE SINGLE BIGGEST MISCONCEPTION ABOUT YOUR BREED?
That Chihuahuas are delicate and need to be pampered.
2. WHAT IS THE CHIHUAHUA’S MOST DEFINING PHYSICAL CHARACTERISTIC?
The head. Any other dogs with that apple shaped head are genetically linked to the Chihuahua (as so many breeds are) but without exception, the ChiChi head, including molera and open topskull, is absolutely unique in all of dogdom. Other breeds have large, round eyes but none have that short little button nose and softly luminous eyes that gives the Chihuahua that one-of-a-kind baby doll expression.
3. WHICH BEHAVIORAL CHARACTERISTIC MOST TYPIFIES THE CHIHUAHUA?
Their ridiculously fearless attitude with other dogs large or small, the “terrier-like qualities.” Okay, terriers are like that but they are not in a tiny little Chihuahua body.
4. WHAT IS THE MOST COMMON JUDGING MISTAKE IN CHIHUAHUAS?
Beginning the exam with the hand held higher than the dog’s head. No dog likes that approach but in one that can be snatched up by a hawk, it stimulates the inherent instinct to duck down from anything “flying” overhead. Approach the table with hand held low, palm up, and rest your hand next to the dog for an instant so that he can see what it is.
The handler often has the dog strung up or bait shoved in the mouth so he doesn’t recognize the thing hovering over him as a friendly hand.
5. WOULD YOU PREFER THE BREED BE JUDGED STANDING OR MOVING?
Moving. Again, too many handlers have not read the standard and don’t realize the critical importance of a survival skill like “alert, swift-moving” so they want the dog to stand perfectly still and bait like a statue. You can’t evaluate the static Chihuahua any more than the breed could have survived without being programmed for constant motion. And the soundness to evade an eagle’s claws or landing in the cooking pot!
6. WHAT COSMETIC ALTERATIONS SHOULD JUDGES KNOW ABOUT?
I don’t know of any that really pertain to this breed. Tail carriage has a lot of latitude, dentition isn’t the end of the world in any toy breed, and any colour is correct in the Chihuahua so there is no incentive to alter anything.
Extreme heads. Eye-catching exaggerated heads. Having said that, what should be of the most concern is to STOP IT before we destroy the breed. The tiny button (called a nose) stuck on a paper plate profile that contains dangerously large eyes mounted on a misshapen topskull should be of great concern to judges as well as breeders.
8. WHAT IS THE MOST ENDEARING QUALITY OF YOUR BREED?
Although they are the most “pack oriented” breed I know, the Chihuahua will forsake the company of any dog, any time, under any circumstance in order to be in a human lap.
9. WHAT ARE THE THREE WORDS THAT BEST DESCRIBE THE CHIHUAHUA?
Most Ancient Lapdog
And You Think You Have Stress!!!
The Chihuahua –
No, it’s not a rat, nor a toy – it’s a dog, a real dog, with teeth and attitude. Tiny in size but large in spirit, the Chihuahua is one of those highly evolved breeds that has managed to convince most humans that it should be carried around everywhere. Of course for a Chihuahua simply walking down a sidewalk or hanging out in the kitchen can be a risky business. At less than six pounds, a little buddy subjected to a careless misstep by a human can be badly injured. However most Chihuahuas are very affectionate anyhow and prefer cuddling close to their humans.
The Chihuahua is an old breed with an obscure history. Most believe that it originated in Mexico with the Mayans, Toltecs and Aztecs, but other less favoured theories suggest Egypt, Malta, or even China. Certainly the indigenous people of Central America kept small dogs that the rich seemed to revere enough to want buried alongside themselves after death. The dogs were apparently ritually sacrificed after their masters died, under the belief that the sins of the master were then transferred to the dog, ensuring safe passage of the (human) soul to its final resting spot.
If Chihuahuas have a negative reputation, it is often that they seem “snappy,” “yappy” or “sharp.” In part this is probably due to their strong attachment to their humans (they are not particularly drawn to strangers) and the fact that everything else in the world is so big. It can also be a result of poor breeding. However a large factor in the behaviour of any dog derives from the attitudes of its human caregivers. With a dog that can be carried around like a baby and whose bite is a joke (though from personal experience, a Chihuahua bite is not always funny), owners are often overindulgent and can lack a sense of the need for training. A Rottweiler must be trained. A badly behaved or poorly socialized Chihuahua, on the other hand, is unlikely to get an owner into much trouble.
The Chihuahua is a great city dog and a fine little buddy. Contrary to the beliefs of many, it is a true dog if treated as such, and will reward a loving human family with great charm, loyalty and affection. Tiny breeds have special needs (for example, they cannot be left outdoors) but are easier to keep in countless ways. If your lifestyle suits a Chihuahua, a Chihuahua may suit you. But be prepared to buy new colour coordinated clothing as he will probably want to be in your arms a lot.
Chihuahua’s often suffer from what is called, luxating patellas. The kneecaps on the rear legs slip out of place causing pain, stiffness and difficulties walking. This can sometimes be a severe problem. It is a common condition for smaller breeds. If your Chihuahua suffers from luxating patellas you should have him checked out by the vet. In mild cases the dog will be fine without medical interference and should be able to live a normal life. In severe cases, however, your dog may need surgery to correct the condition.
Patellar luxation in chihuahuas can have both genetic causes, or environmental causes (luxation due to injury). If it appears at an early age, it’s likely to be due to genetic causes. environmental sources of injury can include too much jumping (i.e. jumping off furniture), or too much stress on the patella and surrounding ligaments (ie. when a chihuahua dances on its rear legs). This is especially dangerous when a chihuahua is a puppy in stages of early development.
Adult chihuahuas can also damage their kneecap by a forceful hit or blow. With age, looseness might also be recognized, especially in chihuahuas that are overweight as there is constant pressure on surrounding ligaments.
Symptoms of patellar luxation includes skipping, yelping when in pain, holding the rear leg up for a short time as they walk or run or rear-leg weakness. If left uncorrected, the condition will result in serious wear of the patellar ridges where the groove becomes very shallow resulting in both arthritis and in the more serious cases, permanent crippling.
If your chihuahua does have patellar luxation, see your veterinarian for options to help alleviate symptoms. The use of supplements such as glucosamine may be helpful and it’s recommended that you keep your chihuahua lean and exercised to keep the leg muscles strong.
Depending on how severe the condition is, it may or may not require surgery. If required, your chihuahua will recover quickly with complete recovery in as early as thirty days. Breeding chihuahuas with this disorder is not recommended. Chihuahuas affected still make for wonderful pets and those that do require surgery usually lead perfectly normal lives without any restrictions on activity.
Hypoglycemia is a common condition in Chihuahua’s. Hypoglycemia is low blood sugar.
This is especially dangerous for puppies. Left unattended, hypoglycemia can lead to coma and death. This can be combated with frequent feedings (every three hours for very small or young puppies). Chihuahua owners should have a simple sugar supplement on hand to use in emergencies, such as, Nutri-Cal, Karo syrup or honey. These supplements can be rubbed on the gums and roof of the mouth to rapidly raise the blood sugar level. Signs of hypoglycemia include lethargy, sleepiness, low energy, uncoordinated walking, unfocused eyes and spasms of the neck muscles (or head pulling back or to the side).
Chihuahua’s are generally healthy, despite all the Chihuahua health problems described. Most conditions are easy to control and as long as you schedule regular check ups with the veterinarian your dog should remain in good health. Prevention and good Chihuahua care is the key to keeping your Chihuahua healthy.
Because the Chihuahua is small, he also has a very small mouth. This small mouth can cause problems with the mouth being too small for the teeth, which causes overcrowding. Overcrowding of teeth can cause food to be trapped between the teeth, resulting in plaque and tarter buildup, as well as premature tooth-loss. Keeping the teeth clean is essential to keeping the mouth and the rest of the dog healthy. Dogs that have dirty teeth are found to be at much more at risk of heart, liver and kidney damage from the bacteria entering the bloodstream.
You can help keep the mouth clean by offering dental biscuits, dental chew toys, including edible dental chew toys (i.e. greenies, dentabones, etc.), feeding dry food instead of semi-moist or canned food, brushing your dog’s teeth (but don’t use human toothpaste…it has fluoride…there are doggie toothpastes available at most pet shops), using the available edible water additives for dental hygiene, as well as taking your dog to the veterinarian for a dental cleaning, etc. As the Chihuahua gets older, it is almost inevitable that he will need at least one dental cleaning by the veterinarian, quite often more.
Another issue, although less serious and easily corrected, is retained puppy teeth. Toy breeds are more prone to this problem, and it is caused by the adult tooth growing beside the puppy tooth, instead of the puppy tooth falling out. I usually recommend that if there are any retained puppy teeth (the usual teeth to be retained are the long canines and the small incisors in the front), that the puppy teeth be removed at the time of spay/neuter. This way the dog is only under anesthetic once, and for the rest of his life food can’t get trapped between the puppy and adult teeth
Chihuahuas have moleras, or a soft spot in their skulls, and they are the only breed of dog to be born with an incomplete skull. The molera fills in with age, but great care needs to be taken during the first six months until the skull is fully formed. Some moleras do not close completely and will require extra care to prevent injury. Many veterinarians are not familiar with Chihuahuas as a breed, and mistakenly confuse a molera with hydrocephalus.
SA FCI Africa International Show: 31 May 2013
Chanel took second place in the Toy Group Final.
Judge: Monique van Brempt (Belgium)
This gallery contains 4 photos.