Dr. B.W. Ziessow wrote, "By definition, conformation in any breed is the symmetrical formation and arrangement of (body) parts; conforming to a model or a plan (i.e., the breed standard). The first question that must come to mind in judging any breed or evaluating an individual specimen is "Can the dog do the job he was originally intended to do?" It is axiomatic that proper conformation is basic to the survival of any breed and is equally important to both the show dog and the hunter. It is ludicrous therefore, to think of type as something extra to breed conformation and/or soundness (which is tantamount to proper movement). Without them you can't have true breed type. Accordingly, there is one (and only one) correct type of Labrador Retriever."  
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A Labrador Retriever should be able to excel in field work and have the quality to win in the show ring. After a hard day's work in the field, under difficult conditions, he should be able to be a nice companion and friendly, relaxed family dog.   
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Is there a difference between show dogs and working dogs? 
Yes, there is. Many Labradors who win ribbons, medals and cups at dog shows (and are used for breeding), are physically unable to do the job the Labrador was originally intended to do, and many Labradors being run in field trials (and are used for breeding), don't come up to the breed standards of conformation and soundness.  
This is a very disturbing situation. 
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"Show types" and "Field types" - a breed split 
In the United States the show bred Labradors are often called "English", while the field bred Labradors are called "American". For more than 60 years however the breed split exists on both sides of the Atlantic. In England the Buccleuch kennels, for instance, have always concentrated on field work. Even in the 6-generation pedigree of Buccleuch Virginia, born in 1995 and a nice example of linebreeding back to Swinbrook Tan, you will not find one Show Champion, but many, many Field Champions. 
Show bred Labradors, and this is a fact, are usually stockier with more "bone" and coat. They have larger, blockier heads and otter tails. They are more easy going and laid back than their field bred counterparts. Field bred Labradors are bred for working. They are usually taller and leaner than show types, tend to have thinner faces, tend to suffer from separation anxiety, and forget about the otter tail that is so typical of the breed. They are very hyperactive, and never want to stop playing & fetching. (Many people would call them "nervous" or "edgy".) There is, however, a difference between British bred and American bred working Labradors.  
In my "Labrador Typecasting" I describe the field type as "Whitmore".  
No distinction between the "show" or "bench" type and the "field" or "work" type however is made by the Kennel Clubs, but it is a fact that the two types come from different breeding lines and we have to live with that fact. 
A simple combination of a show bred Labrador and a field bred Labrador isn't the right method to get a multi-purpose Labrador. First of all this outcross would be a waist of good and trusted bloodlines, and you just might end up with a litter of edgy, skinny, snipe-faced Labrador puppies that are completely useless for field work. Secondly, the hereditary syndrome of Exercise Induced Collapse (EIC) is recently being observed with increasing frequency in young adult Labrador Retrievers, and most affected dogs have been from field-trial breedings. (In this video of an EIC episode you can clearly see that the affected dog is a "field" type.) 
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Being a Labrador breeder I aim to breed multi-purpose Labradors - Labradors that are wonderful family dogs, good looking Labradors, Labradors that can work in the field. Yet I have always kept a certain distance from the pure field bred, because I don't like the way they look and I don't like the way they behave in the living room. The closest I got to introducing a field bred to my bloodlines was acquiring a bitch who's sire was from pure and familiar (trusted) "show" lines, while her dam's sire was also pure "show" line and her dam's dam had a field bred as a great-grandmother. This bitch wasn't the best looker in the world, but she was a wonderful family pet and had good hunting qualities. She - in combination with pure show bred dogs - gave me three litters of excellent puppies.  
For me it's quite a risk to take my chance with a Labrador that has "field" lines in its pedigree, even more now we've got this hereditary syndrome of Exercise Induced Collapse (EIC). So I don't do it.   
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Since the Kennel Clubs and most Labrador Clubs refuse to admit there's a difference between show bred and field bred Labradors, and therefore refuse to publish information about this subject, I feel that we, the breeders, are obligated to inform the public in general and our puppy buyers in particular about these differences. 
Labradors are NOT right for everyone. Labradors are a breed that need a lot of exercise, and if you cannot provide that, then forget about this breed. Labradors from show lines tend to gain weight easily because they do not have such a high drive as field bred Labradors, but dogs from both strains need plenty of exercise.  
Even if you want to acquire a Labrador mainly for working purposes, it's safer to get it from show lines with working abilities (applies to most show bred Labradors) than from pure field lines.  
Also I need to stress once more that the British breed different types of field Labradors than Americans, and that they train their dogs differently. Because the British absolutely must train retrievers that are steady and quiet under considerable pressure -- say while 200 or more pheasants are felled in a driven shoot -- they believe that starting a dog too soon on field work tends to create a dog whose retrieving expectations will rise to intolerable levels, and with them the amount of maintenance required to keep a Labrador steady, quiet and otherwise well-trained. Again, the best of the British Labrador breeders produce animals of kind and quiet temperaments because the British are highly discriminating breeders. And again, steadiness and quietness are qualities of temperament, and temperament can't be trained, it must be bred for. The British have long known, however, that certain training techniques and philosophies accentuate these desirable genetic qualities. A dog that inherently is capable of being steady and quiet in the field can be assured of fully developing those traits if certain training techniques are followed. Conversely, the same animal can be developed into a much more excitable, less quiet and less steady dog if training techniques are used that -- intentionally or not -- tend to hype up, or excite, a dog. So there certainly is an aspect of environment, too. In Britain, the Labrador was, and still is, used primarily for upland game hunting, often organized as a driven bird shoot. Typically, separate breeds were used for different tasks; and the Labrador was strictly for marking the fall, tracking and retrieving the game. But in the United States and Canada, the breed's excellence at waterfowl work and game finding became apparent and the Labrador soon proved himself adaptable to the wider and rougher range of hunting conditions available. The differences between British and American field trials are particularly illustrative. 
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American breeders of gundogs, by comparison, often begin throwing retrieving dummies and even pigeons when puppies are only a few months old. They often breed a different type of field dog and prefer the hyperactivity to kind and quiet temperaments.   
A pure American field bred Labrador is usually itching for a job and is always eying a ball, even when lying down, which you are likely to see rarely. It cannot seem to catch the concept "That'll Do". It always wants to run, and is always hopping and jumping. Huge amounts of daily exercise are a must. Because these dogs are so active, not having enough exercise can lead to extreme cases of aggresion, which happens quite often. They will take out their frustration on other animals if they do not have enough exercise. American field bred labradors are bred to be constantly swimming, working, fetching in the field for hours on end. Their muscles twitch for activity at a constant rate. They are not the right type of dog for most people. Daily training is a must and do not even consider an American field bred Labrador unless you are planning on getting one for much more than a pet. Hunting and agility are two excellent sports of this type of dog. Both British and American field bred Labradors can make wonderful pets, but they do require tons and tons of mind stimulation. 
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