Copyright=20 1995.=20
Table of Contents
- I=20 want to make some money!=20
- Every=20 bitch should have a litter!=20
- But my=20 dog is registered!=20
- Eyes=20
- Hip=20 and joints=20
- Frequency = of Breeding=20
- Care = of the=20 Pregnant or Nursing Bitch=20
- Caring for=20 the Puppies=20
- Placing=20 the puppies
Should I Breed My Dog?
You = may be=20 wondering whether or not you should breed your dog. Here is some = information.=20 The summary is that if you want to do it right, and get healthy and = happy=20 puppies, it is very expensive and a lot of work. Many people have = written=20 several treatises on this subject includingRemember that you are going to need a vet that is familiar with = whelping=20 dogs. This will be your best resource, as well as any long-time breeders = that=20 you know. Not all vets are knowlegeable about whelping so be sure to ask = around=20 and especially look for recommendations from local breeders that you may = know.=20
I want to make some = money!
Breeding, and=20 doing it right, is an expensive undertaking. By the time you've picked = out a=20 good bitch, waited for her to grow old enough (minimum age: two years = before=20 breeding), picked out the best dog to mate her with, gone through all = the health=20 checks she needs, ensured that the dog you want to use also passes the = same=20 health checks, you've invested a lot of time and effort. You still have = to pay a=20 stud fee (or give a puppy back), you have potential extra expenses = during=20 pregnancy, you have the time and expense of whelping (either you take = time off=20 from work or something goes wrong and you have to take her in to the = vets). You=20 need to keep the puppies for a minimum of 8 weeks before sending them to = their=20 homes; you need to advertise and find good homes for the puppies, you = need to=20 make sure they have had their shots before going. You may have possible = vet=20 bills if the puppies require extra attention. If some of the puppies = die, or you=20 have a smaller than usual litter, you may not get as much money from the = sale of=20 the puppies as you had though. There are even potential problems later = on with=20 dissatified customers! You are better off consulting with a financial = wizard=20 about investing the money you would otherwise spend and lose on = breeding!=20Breeders frequently count themselves lucky if they break even. =
My kids should see the wonders of birth = and=20 life!
What if the whelping goes wrong and dead puppies are born? = What if=20 the bitch dies? These are all very real risks that you are undertaking. = Much=20 better alternatives include videotapes that are available. If there are = local=20 4-H clubs, those provide alternatives for children.=20Or, you could contact your local shelter and see if there is a = pregnant bitch=20 about to whelp or a litter of puppies that need to be raised and = socialized=20 before being adopted out. This would allow you to find out just what = this could=20 entail, while helping the shelters rather than potentially contributing = to the=20 problem.=20
I want another dog just like = mine!
If you=20 want to breed your dog so as to get another dog like yours, think about = this for=20 a moment. No matter how special your dog is to you, a puppy out of it is = not=20 guaranteed to be just like or even similar to your dog -- half its genes = will be=20 from another dog! You will have to find another dog that also has the=20 characteristics you want in your puppy; that dog will have to be = unneutered; and=20 the owner of that dog will have to be willing to breed her/his dog to = yours. It=20 is much easier, often less expensive, and certainly less time consuming = to pick=20 out an existing dog that you like from the shelter or another breeder. = Best yet,=20 go back to the same breeder of your dog, if possible, and pick another = puppy out=20 of similar lines.=20Every bitch should have a litter!
This = is flat=20 out wrong. Bitches are not improved by having puppies. They may undergo=20 temporary temperament changes, but once the puppies are gone, = she'll be=20 back to her old self. Nor is it somehow good for her physically. In = fact, you=20 will put her at risk of mammary cancer and pyometra. There is absolutely = nothing=20 wrong with spaying a bitch without her having a litter.=20But my dog is registered!
Well, yes, = but that=20 doesn't mean a whole lot. A registered dog, be it AKC, UKC, CKC, = etc.,=20 simply means that it's parents (and their parents) are also registered = with the=20 same registry. This confers no merit in of itself, it simply means that = the=20 dog's parentage is known.=20Most registries do not make any assertions of quality in the dogs = they=20 register (except for some limited breed-only registrations, but these = are=20 uncommon). They do not restrict the breeding of their dogs and hence = there is no=20 guarantee that a registered dog is a good specimen of its breed.=20
The AKC has just started a "limited registration" program whereby = puppies out=20 of such dogs are ineligible for registration. It remains to be seen what = the=20 overall impact on AKC dog breeds will be. Other registries have used = similar=20 programs with good results.=20
So I should breed when...?
The = only=20 reason you should be breeding is that you honestly feel that you are = improving=20 your breed by doing so. There are far too many dogs in the country to = breed=20 without good reason. A dog in a breeding program must be one whose = genetic=20 history you or its breeder is intimately familiar with. Such a dog must=20 represent the best efforts of its breeder at that point. Such a dog must = have=20 good points to contribute, whether that is in good conformation, good=20 performance or whatever. Such a dog must have some evidence of external=20 evaluation. That is, others besides the breeder or the owner must also = think=20 that the dog is a good representive of its breed. That usually = translates into=20 titles, whether for conformation, obedience, field, herding, or whatever = is=20 appropriate for that breed. Such a dog must be tested as it matures for = any=20 problems that tend to appear in its breed, whether that is hip = dysplasia,=20 patellar luxation, von Willebrand's, cataracts, PRA, fanconi syndrome, = subaortic=20 stenosis, etc.=20Potential Hereditary=20 Problems
Every breed has a different set of potential problems = for it. I=20 have listed common ones below, but this is not to say that all dogs must = be=20 checked for everything listed. You need to do research in your breed to = find out=20 what the common problems are. You will also need to research the = particular=20 bloodlines you are using to see if they are prone to any additional = problems you=20 want to know about and screen for as well.=20Eyes
Most breeds require eye checks of some = sort, for a=20 variety of problems. These include, but are not limited to problems such = as=20- Progressive Retinal Atrophy (PRA). This disease eventually causes = total=20 blindness. In some breeds the onset is quick, before the dog is two or = three.=20 In others, the onset is much later, when the dog is four to eight = years old=20 (and may have already been bred). Irish Setters have a test available = that can=20 detect carriers and affected dogs; other breeds do not have this = recourse. It=20 appears to be a simple autosonomal recessive, but the late onset = complicates=20 breeding programs. If a dog is affected, then both parents are either = carriers=20 or also affected.=20
- Retinal Dysplasia. Causes eventual blindness. This is believed to = be=20 hereditary. Some dogs can be detected with this condition in puppy = hood, but=20 carriers cannot be identified until they produce such puppies.=20
- Collie Eye Anomaly (CEA). This affects the collie breeds (bearded, = border,=20 rough, smooth) as well as some closely related ones. This condition = has=20 varying degrees of severity from hardly affected to blind; the problem = is that=20 this disease is inherited and two hardly affected dogs may easliy = produce a=20 severely affected dog.=20
- Cataracts. There are many forms and causes for cataracts, but some = forms,=20 such as juvenile cataracts, are inherited and such dogs should not be = bred.=20
- Entropion, Ectropion: These are conditions in which the eyelids = turn in or=20 out, causing various problems and often pain for the dog. =
Hip and joints
There are a variety = of joint=20 problems found in most breeds. Toy breeds can have joint problems too; = just=20 because your breed is smaller doesn't mean you can figure you are free = of hip=20 dysplasia and be done with it. There are several problems that = specifically=20 affect smaller dogs!=20- Hip dysplasia is probably the best known problem. This is a = malformation=20 or deterioration of the hip joint, so that the socket it sits in is = too=20 shallow to secure the head of the femur. As the condition progresses,=20 arthritic changes begin to destroy the protective cartilage and the = dog may=20 experience severe pain if the condition is bad enough. Some dogs are=20 asymptomatic, but still should not be bred. This condition primarily = affects=20 the medium-to-large breeds, but smaller breeds have been known to be = affected,=20 for example Cocker Spaniels and Shetland Sheepdogs can have this = problem. To=20 make sure your dog is free of hip dysplasia, you need to have the hips = radiographed and then obtain an expert analysis of the xrays. Your vet = isn't=20 necessarily the one to do this! In the US, you would mail the xrays to = the=20 Orthopedic Foundation of Animals and wait several weeks for their = evaluation.=20 In Canada, Europe and Britain, there are equivalent programs, but all = differ=20 in the type of certification and age at which they will certify; some=20 organizations certify after one year of age, others certify after two = years of=20 age.=20
- Osteochondrosis Dessicans (OCD) is an elbow joint problem. A bone = spur or=20 a flake wears away at the joint which becomes stiff and painful. Xray=20 evaluations of these joints are also needed. Many breeds that are = prone to hip=20 dysplasia may also have OCD.=20
- Patellar Luxation is a problem affecting the kneecaps. Smaller = dogs are=20 more prone to this problem than larger ones are. The kneecap will = slide out of=20 place and lock the leg straight. Diagnosis is fairly straightforward = and=20 surgery can correct the problem, but no dog with patellar luxation = should be=20 bred as this is also an hereditary condition.
Other things to check for
- In some breeds, deafness is a potential problem. Puppies at risk = should be=20 BAER tested and any that fail should be neutered.=20
- Heart conditions in many breeds must be checked for. = Subaortic=20 stenosis (SAS), other malformations of the heart or valves.=20
- Hemophilia type of problems, e.g., von Willebrand's disease and = others.=20
- Malabsorptive syndromes, digestive problems.=20
- Epilepsy.=20
- Allergies.=20
- Incorrect temperament for breed.
Medical Checks before=20 Breeding
You must make sure the bitch and the stud both are free = from=20 brucellosis before breeding them. Brucellosis causes eventual sterility = in both=20 sexes (sometimes non-obviously) and can cause a litter of puppies to be = aborted=20 or die shortly after birth. In addition, brucellosis is on occasion=20 transmissible to humans via the urine or feces of an affected dog. = Between dogs,=20 it is most commonly passed in sexual intercourse, although an entire = kennel can=20 be infected through contact with secretions.=20The sire should be in excellent general health. The dam must = be in=20 good health, to withstand the stresses and rigors of a pregnancy. They = must both=20 be up to date on their vaccinations.=20
Temperament
Never breed any animal = that has=20 temperament problems. In particular, this has been the cause of the = degeneration=20 of many breed's general temperament: Doberman Pinschers, Rottweilers, = and so on.=20 If your animal is untrustworthy around people, overly aggressive to = people,=20 excitable, or is a fear-biter, do not breed it. If it is shy or = submissive,=20 don't breed it. Look for happy, confident and obedient animals, and = consider=20 carefully the particular temperament requirements for your dog's breed.=20There are a variety of tests to indicate a dog's temperament. Many of = the=20 working breeds have a temperament test (for example, the Doberman's WAC = test)=20 for their breed. AKC has a Canine Good Citizen test (open to all dogs) = that=20 gives some indication of the dog's temperament (and, yes, training). = Therapy=20 Dogs International and other Therapy Dog clubs have temperament testing = that=20 does try to separate out actual temperament from training. Obedience = titles can=20 be (but are not necessarily) an indication of good temperament.=20
Pedigree Research
You must = carefully=20 consider each dog's pedigree for compatibility. Try to select strengths = to=20 offset weaknesses. Do not allow your bitch to be bred to an unsuitable = dog, and=20 conversely, be picky about the bitches you allow your dog to breed. This = phase=20 alone requires considerable research to find a suitable candidate, and = you=20 should definitely work closely with a knowledgeable person, ideally the = breeder=20 of your dog. Simply because two dogs "look good" or even *are* good does = not=20 mean that they necessarily complement each other: suppose they are both = carriers=20 for the same disease? Suppose they both have a tendency to overbites or = other=20 disqualifying faults?=20Be honest with yourself. If your dog is not a good representation of = its=20 breed, do not let it reproduce. It is much easier to improve a few = faults than=20 to try and get excellent pups with a mediocre dog. Check the breed = standard for=20 your dog and ask a knowledgeable person for their evaluation of your = dog.=20
We'll return the the importance of scrutinizing a pedigree in the = genetics=20 section below.=20
Frequency of Breeding
Ideally, a bitch = should only=20 be bred every other year and she should not be bred much before two = years of=20 age. The season closest to the second birthday is a good one to start = with;=20 certainly no earlier than this. In some breeds, you may need to wait one = more=20 season before beginning. By this time, she is better prepared mentally = for=20 having puppies than she would have been with her first few seasons. Her = physical=20 growth is complete and pregnancy at this point won't endanger her = health,=20 provided that she is healthy to begin with.=20In breeds with Hip Dysplasia, many people wait until after two years = of age=20 so that the parents can be certified; however if you have sent in xrays = to OFA=20 for preliminary evaluation and they came back as fine, many breeders = consider it=20 safe enough to then breed on the season closest to the second year, = which can=20 wind up being before the bitch is actually old enough to be certified. = (And when=20 the bitch is old enough, she is, of course, duly certified.) But the = preliminary=20 xrays must be examined by OFA, not by a local veterinarian. There = are=20 many dysplastic dogs out there that had vets look at their xrays and = pronounce=20 them "wonderful."=20
It's important, however, to keep the frequency of breeding low. Even = at=20 maximum, you want to allow at least one unbred season between breedings. = This=20 allows your bitch to rest and regain her strength. A bitch that whelps = too often=20 will produce weaker puppies more likely to die, and the repeated = pregnancies are=20 pretty rough on her, too.=20
For dogs, they should definitely have all their certifications = necessary. For=20 many breeds this means that they should be over two years old. Since a = dog can=20 be bred at any time, unlike bitches, waiting for two years is not a = problem,=20 whereas a bitch often has a season just before two years of age and then = has to=20 wait until 2.5 or three which sometimes presents problems in trying to = time her=20 litters. But this does not apply to a stud dog, so he should definitely = have all=20 of his checks and certifications before being bred. Frequency is not = generally a=20 problem although some dogs have problems with sperm production if they = breed=20 once a day for several days. They need top-quality feeding and care if = they are=20 going to be bred often.=20
Care of the Pregnant or Nursing Bitch
You = should make=20 sure the bitch is up-to-date on all her vaccinations, medications, and = shots=20 before she is bred. She will require supplementary food during the last = three=20 weeks or so of pregnancy. In general, puppy food is formulated both for = puppies=20 and pregnant or nursing bitches.=20She should be under the care of a vet for any related problems. Dogs = can have=20 miscarriages. Illnesses, diseases, or infestations that the bitch picks = up=20 during her pregnancy can affect the puppies. Difficulties during = whelping are=20 entirely possible, and the rule for some breeds. You must be prepared to = get her=20 to the vet quickly in an emergency.=20
There are instances of "mummy puppies" where you have a puppy whose=20 development went awry, but it was not aborted. Instead, it dries and = shrivels=20 up, and when born, looks like a mummified puppy, blackened and ready to = rot.=20 Overbreeding and inadequate care are usually the causes. It is quite = likely that=20 the dam will come down with an infected uterus after such a puppy. = "Water=20 puppies" are another type of problem in which the dead puppy appears to = have=20 never properly developed a skeleton and appears to be full of gelatin. = This=20 seems to be linked to a viral exposure.=20
Other congenital (but not genetic) defects can include: no anus, = cleft=20 palates and hare lips. These conditions require corrective surgery or = the puppy=20 will die.=20
While the bitch is nursing the puppies, she will require about three = times=20 the amount of food she normally eats! It is also common for nursing = mothers to=20 go out of coat at this time.=20
Caring for the Puppies
Prewhelping preparations
You should = have a=20 sturdy, clean, proper sized whelping box for the litter. It MUST include = a "pig=20 rail" around the edge to prevent the bitch from laying on or smashing = her pups.=20 It should be big enought to allow the bitch to turn around but small = enough to=20 prevent the pups from being "lost" in the unused portions. About six = inches=20 longer than she is, fore and aft, when laying prone (as in suckling her = puppies)=20 and about a foot on either side length wise.=20To get the whelping box ready for your bitch, get a sheet of plastic, = such as=20 you would use for painting a ceiling to protect the floor. Cut it up = into=20 several pieces the size of the whelping box. Put one piece of plastic = down,=20 several layers of newspaper, another piece of plastic, more layers of = newspaper=20 and so on for four or five layers. Then when your bitch is whelping = puppies, you=20 can roll off a layer when it gets messy -- and it will! -- and throw it = away to=20 instantly clean the whelping box.=20
Postwhelping
After the puppies are = born, there=20 are many strategies for lining the whelping box. Some people continue to = use=20 newspapers, but puppies get pretty dirty from both newspaper print and = feces.=20 Other people have had success with synthetic materials on top of = absorbent=20 materials: the synthetic material provides secure footing, but the urine = and=20 other liquids pass through it to leave it dry. Other people use pine = shavings=20 (about six inches deep). You will do a lot of laundering to keep things = clean no=20 matter what you use. You will also have to clean the feces out of the = whelping=20 box after your bitch decides that's no longer her job.=20Newborn puppies MUST be kept warm. The temperature in the whelping = box at=20 birth should be 90 F. The temperature can then be decreased 2 degrees = every=20 other day. NEVER FEED A CHILLED PUPPY!!! If a puppy becomes chilled it = will cry=20 continually and it will tuck its tail between its little legs. A = healthy, happy,=20 litter will "purr" like a swarm of bees and when feeding their tails = will be=20 straight out from their bodies. Warm any chilled puppy by putting the = puppy=20 under your shirt and under your armpit. The best method of warming a = puppy is to=20 use a special whelping box heating pad with a towel over it to prevent = soiling=20 the pad. Make sure the temerature does not go too high. Heating lamps = are ok but=20 puppies can become dehydrated. If the litter clumps together and cries, = they are=20 too cold; if they separate and try to hide under shade, they are too = hot.=20
Large litters will require supplemental feedings if you want all the = puppies=20 to survive. Your bitch may not be able to care for a very large litter. = You will=20 need to get the pups rotating on shifts. For the first two weeks you may = have to=20 supplement as much as every four hours. Use a good prepared = milk-supplement=20 especially formulated for puppies. If you get in a bind you can use a = goat-milk=20 reciepe avilable in most books about breeding and whelping pups. You may = have to=20 tube feed those pups that will not suckle from a bottle!=20
Are you going to remove the dewclaws or dock a tail? This must be = done by 3=20 days old at the latest! Any later will not heal as nicely or quickly!=20
If you have a purebred litter, you must record the date of birth and = all of=20 the pups (including the dead ones) in your record book. Then you will = need to=20 fill out and send in your litter registration form. You want to do this = as soon=20 as possible, since many registries can take up to 6 weeks to return the = forms=20 for individual registration to you (which you will want to give to your = puppy=20 buyers later).=20
You will have to keep the whelping box clean. For the first two weeks = the=20 bitch will keep the pups pretty clean, but the bedding should be changed = twice a=20 day at minimum. Starting week three, the pups start to eliminate some on = their=20 own.. then you will need to clean much more often!=20
At four weeks, the pups usually become very active and it this time = may=20 require a larger area then the welping box...you will need a large = ex-pen or=20 some way of confining them safely. You do have a place to keep them that = they=20 are safe in and can't destroy? Puppies at this stage can devastate a = room or=20 garage in hours.=20
At week five you will probably want to introduce the pups to weaning = food.=20 Usually you will have to mush up the dry puppy food for the pups to be = able to=20 eat it. Use warm water and let the food stand in a bowl for about 2 = hours.=20
At week six you should vaccination and worm the pups, and have them = checked=20 for heartmurmers, hernias, males for testicles (yes you should be able = to feel=20 them at 6 weeks!), deafness, and eye problems.=20
You should be socializing now too... And are you going to do any = puppy=20 testing for temperaments? At seven weeks you should be calling up those = poeple=20 with deposits on your pups and getting your paper work all sorted out. = Are your=20 spay/neuter contracts ready? How about pictures of the pups for your = clients?=20
And this is just if everything goes perfectly! What happens if one of = the=20 pups has a heart murmer, or a hernia? What about a deaf puppy? What if = your=20 whole litter gets parvo or distemper? What happens if one of the pups is = affected with "swimmer-puppy" syndrome? What about fading-puppy = syndrome? What=20 happens if your bitch gets an infection or mastitis? What if she dies?=20
Placing the puppies
After the puppies are = born, if=20 not before, you must consider placing your puppies. Time and time again, = people=20 breed a litter because friends and family want one of their dog's = puppies -- and=20 then none of them will take one.=20At six weeks is when even seasoned breeders wonder why they do this. = A=20 healthy active litter of six will run you ragged at this age. They are = so=20 curious, they want to explore everywhere, and they are at the prime age = for=20 socialization and exposure to many things that you, as a responsible = breeder,=20 want to give them a head start on.=20
At eight weeks, you may begin placing those pups that are ready to go = to=20 their new homes. Insecure pups may need more time, how are those puppy = tests=20 coming? You can't place puppies earlier than 7.5 weeks or so (no matter = how much=20 you may want to).=20
Are you prepared to do some legwork to find GOOD homes for them, not = just=20 hand them off to the first person who comes by? You are aware that you = won't=20 always be able to sell all of your puppies locally, aren't you? What = assurances=20 do you have that the puppies will not wind up filling animal shelters, = facing=20 death because their parents were thoughtlessly bred? Suppose you wind up = keeping=20 more of the litter than you intended to? Suppose some of your puppies = are=20 returned? Can you keep the extra puppies?=20
Considerations for Stud Dogs
First, = remember that=20 it is extremely difficult to come up with a top quality stud dog that = people=20 want to use. After all, they will look around and pick out the best male = they=20 can find. So your dog has to be pretty impressive to be noticed in the=20 competition.=20Your male should be in top condition. He should be certified clear of = joint=20 problems (and in many cases that means he has to be at least two years = old). His=20 eyes should be checked annually. He should be clear of any abnormalities = common=20 to his breed. No heart problems, no seizures, no thyroid problems, etc. = He=20 should be clear of brucellosis. His temperament should be good, and = appropriate=20 for his breed. If you have such a dog, you will need to get your dog = well known.=20 This generally involves showing your dog (in show, field, or obedience) = and=20 doing other work with him. An unproven dog (that has no previous puppies = or only=20 puppies too young to evaluate) will command a much lower stud dog fee = than a=20 proven dog (with a record of puppies to examine).=20
You must be prepared to board the bitch. The common procedure is for = the=20 bitch to be shipped out to stud, so you will need facilities to board = bitches in=20 heat. These facilities should be adequate for up to a week of boarding = and to=20 prevent any mismating. You might wind up with more than one bitch at a = time --=20 can you board them all safely?=20
You must monitor the mating and be ready to intervene if necessary. = Some=20 breeds require intervention (such as Basset Hounds). Not all dogs or = bitches=20 understand what to do, especially if it is the first time for one or the = other.=20 It can be disastrous if two dogs are left alone to mate. Additionally, = if the=20 mating doesn't take, are you prepared to go through the whole thing = again the=20 next time the bitch comes into season? Typical contracts call for free = repeat=20 breeding in the case two or less puppies occur or the breeding doesn't = take.=20
You need to be able to evalate the bitch's pedigree for compatibility = with=20 your dog's. Any good points or bad points of the litter are (rightly or = not)=20 attributed to the sire, so your dog's reputation is at stake with each = litter he=20 sires. You should be reasonably confident that the proposed breeding = will result=20 in good puppies.=20
If the owner of the bitch is a novice, are you prepared to assist = with advice=20 on whelping and puppy care? These people will expect you to have the = answers.=20 Sometimes entire litters of puppies are dumped on the stud dog owner = when the=20 bitch's owners can no longer cope with them because they didn't realize = what a=20 responsibility caring for a litter involved. Are you ready to take care = of and=20 place your dog's offspring if this should happen to you?=20
Are you prepared to deal with cases where you are certain your dog is = not the=20 sire of the puppies but the bitch's owner insists that he is? Or if the = owner of=20 the bitch insists that you must have allowed a mismating to occur when = she was=20 boarded with you? Disputes of this sort can become very ugly very = quickly.=20
Genetics
If a purebred dog of breed X = mated=20 with a purebred dog of breed Y, both meeting health standards for their = breed,=20 is there a better chance the offspring would be healthier than a same = breed=20 mating because the gene pool is larger?=20In terms of health alone the first answer would be that in=20 breeding two healthy dogs it shouldn't matter if they're the same of = different=20 breeds, you're apt to get healthy pups. But this doesn't take into = account the=20 question of recessives. Suppose you breed two dogs of different breeds = that=20 both have the same incidence of a recessive health problem. The pups = would=20 have the same odds of having that health problem as purebred pups of = either=20 breed. On the other hand, suppose the two dogs were of breeds that = have no=20 recessive health problems in common. This would reduce or eliminate = the odds=20 of the puppies of having the health problems of either breed. This is = the=20 classic explanation for the theory of first generation hybrid vigor. = The=20 resulting pups should not be bred though, since they'd have a good = chance of=20 having the recessives from BOTH breeds, so the grandpups would be = inclined to=20 be worse off than the purebred offspring of their grandparents. An = excellent=20 set of articles dealing with "hybrid vigor" can be found in = DogWorld,=20 Jan 1997 by George Padgett DVM. Another very important point to = keep in=20 mind is that when a purebred carrying a genetic defect is crossed with = another=20 breed or mixed breed, the "bad" genes do NOT "go away" even though = they may=20 not be expressed in the offspring. If crossed with another dog = carrying the=20 same defect, the offspring of that breeding will demonstrate = the=20 defect.Purebred dogs have all these diseases, = though! It seems=20 that you never hear about mixed breed dogs with problems.=20
Responsible breeders try to identify genetic diseases their = dogs=20 might be carrying and to eliminate them by careful breeding. It is = ironic,=20 though not surprising, that their efforts to identify and weed out = genetic=20 problems have lead some to cry "look at all the genetic diseases = purebred dogs=20 have!" A moment's careful thought will lead you to the conclusion that = mixed=20 breeds carry the same harmful genes (their parents, or their = parents'=20 parents, were purebreds, after all). The differences are=20When you breed two = different=20 breeds together, what kind of variation can you expect?=20Also, if = you stop and=20 think about it, many mixed breeds are simply not tested for most = problems.=20 When they get older and limp, it's just considered old age, although = it could=20 well be hip dysplasia. When they get older and start to go blind, it = could be=20 PRA, but the owners are unlikely to test for this. It's not that = owners of=20 mixed breeds are bad, by any means, but they are not looking for = possible=20 inheritable problems, either.
- with some recessive disorders (though not all genetic = defects)=20 the disease is less likely to be expressed (though it can = still be=20 inherited by offspring)=20
- you have lesser likelihood of ever identifying or eliminating = any=20 harmful genes your mixed breed may be carrying
Pfaffenberger's book has some interesting data on this. He = did=20 some experiments with four different breeds. They were dogs of = approximately=20 the same size, but very different physical appearance AND behavior. = The=20 results he saw in the first and in subsequent mixed generations are = pretty=20 interesting.=20What = is=20 outcrossing?=20Let's look at a common crossbreeding: "cockapoos" (which are = not=20 purebred dogs, nor registered with any registry). These are crosses = between=20 Cocker Spaniels and Minature or Toy Poodles. The dogs actually vary = quite a=20 bit, some being more poodle like than others, and some being more = cocker like=20 than others. However, they are generally all a small sized, buff = colored=20 shaggy dog. If you breed two cockapoos together (not generally done), = you get=20 an even wider variation of dogs -- some look like Minature Poodles, = others=20 like Cocker Spaniels. The reason for this is the recessive genes = hidden in the=20 first cross that came out in the second generation. This is actually a = visual=20 example of why "hybrid vigor" doesn't hold.
Outcrossing is where the sire and dam are totally unrelated, = preferably for three or four generations. The true form of an outcross = is=20 between two entirely different breeds because in reality the members = of most=20 registered breeds come from a common ancestor (althought it may be = many, many=20 generations back). It is very rare for outcrossed puppies to be = uniform in=20 appearance. Usually there are a very large ranges of sizes, coats, = colors,=20 markings, and other distinctive characteristics. Outcrossed litters = are=20 generally heterozygous, and do not reliably reproduce themselves, so = even the=20 nicest puppy in the litter may not later produce the best puppies.=20How about line breeding?=20Outcrossing is generally used to introduce something new to a line = -- a=20 better head, better colors, better front, etc. Usually the puppies = retained=20 from these breedings are bred back into the breeder's original line to = standardize them back into the line's general characteristics and=20 reproducibility -- with the one desired characteristic. The tricky = part is=20 that other characteristics may come along for the ride!=20
If you are dedicated enough, you can eventually continue breeding = by=20 outcrossing alone (but don't expect instant or quick results). You = should pick=20 dogs that complement eachother well and are similar in general = appearance.=20 This is a long hard road to eventually developing a line. Through = outcrossing,=20 many health problems can quickly be eliminated (or just as quickly = added into=20 your breeding), but usually you do sacrifice some show quality and=20 producibility.=20
You have to remember that dogs that appear totally healthy may be = carriers=20 of genetic problems. To find this out, test mating is done to a dog = that is=20 affected with the genetic problem (resulting usually in puppies that = are both=20 affected and non-affected carriers) or by inbreeding to a related dog = that=20 also doesn't show the signs of being affected (usually littermates are = used)=20 this will usually result in some puppies free of the problem, some = puppies as=20 carriers, and some puppies affected if both dogs carry the problem = gene (this=20 is not as accurate as breeding to an affected dog, but you are less = likely to=20 have to put all the puppies down).=20
There are variations on outcrossing. A "true" outcross could be a = dog that=20 has totally unrelated dogs bred together throughout the pedigree. This = is very=20 rare. On the other hand, "linecrossing" is a form of outcrossing where = dogs=20 from unrelated lines are bred to produce a new line. The sire and dam = are=20 usually very linebred from their prospective lines and the resulting = puppies=20 are varied in appreance, some looking like the sire's line and some = looking=20 like the dam's line and some looking like mixtures of both=20 lines.
Line breeding is when the sire and the dam are distantly = related:=20 e.g., grandsire to granddaughter, granddam to grandson, second = cousins, half=20 cousins, uncle to niece, aunt to nephew..... The general strategy is = that=20 there is a common ancestor that is being doubled up on both sides. So = the=20 desired dog appears several times in the pedigree.=20And inbreeding?=20This is probably the most common strategy in breeding purebred dogs = (and in=20 developing new breeds, for that matter). Though this method, new genes = are=20 slowly introduced and unwanted genes are slowly replaced. The actual = rate=20 varies by how strongly you line breed. It sacrifices little overall = quality in=20 terms of show quality. Usually the puppies are rather close in general = conformation. The only problem with this method is that it often takes = several=20 generations to get poor genes out, (or adding desired genes in) = resulting in=20 many puppies that have the same genetic problems (or virtues) that = their=20 parents have. And then because some breeders are more interested in = winning,=20 they do not place the affected puppies on spay/neuter contracts. This = is both=20 a blessing and a curse for the breed. If the breeder is very careful, = affected=20 pups can be used wisely to prevent loss of quality, but still remove = the=20 affected genes by only breeding the affected pups to known non-carrier = relatives. This way the breeder can again try to "edit out" the bad = genes. It=20 takes longer this way but less show quality is lost in the process. = This=20 process results in dogs that will often reproduce their same level of = quality.=20 This is refered to as reaching homozygous litters (more genes of the = same kind=20 apparent in the puppies).=20
Inbreeding and linebreeding really differ only in degree. = Linebreeding is=20 less likely to cause harm than inbreeding. Inbreeding is not for = novices.=20 Knowledge of genetics and the breed is required for success. For good = results=20 it must be well-planned and breeders must be ready for whatever = problems it=20 presents.
Inbreeding is where the sire and the dam are closely = related:=20 mother to son, father to daughter, sister to brother, half sister to = half=20 brother, cousin to cousin. People disgree about the exact point at = which=20 inbreeding becomes linebreeding. Inbreeding is the quickest way to = find out=20 what poor genes are in the line and what dominant characteristics are = in the=20 line.=20OK, how do pedigrees figure into this?=20Although many people are disgusted with the idea of this family = incest, it=20 is an extremely useful tool for diagnosing what genes are present. If = the=20 genes for bad eyes are present, but hidden or resessive, this will = bring them=20 out to their full extent. If there isn't any bad genes, then the = puppies will=20 be of very close uniformity and very able to reproduce themselves=20 (theroretically). This is a homozygous breeding. The resulting puppies = will=20 have a lot of genetic material that is the same as their parents and=20 grandparents and will be close genetically to each other.=20
Inbreeding doesn't introduce new genes and does not eliminate bad = genes=20 that the line already has. It only shifts them around like a rubix = cube. This=20 often results in litters with high show potential, if the quality was = high to=20 begin with. It shows you what recessives you have lurking in the dogs' = backgrounds -- both good and bad. But there are drawbacks. = Besides the=20 possibility of bad recessives, inbreeding exclusively will eventually = lead to=20 infertility. It's like a xerox machine. After so many copies, you have = to=20 renew the ink. The same with dogs, you have to introduce new genes. No = reputable breeder will use inbreeding exclusively, and many breeders = simply=20 never use it. Usually, you will only find: very experienced breeders, = ignorant=20 breeders, and puppy mills making use of this technique.=20
Inbreeding increases the chance that a gene obtained from the sire = will=20 match one obtained from the dam, both stemming from the common = ancestor(s) on=20 which the individual was inbred. Thus, inbreeding tends to make = animals=20 homozygous rather than heterozygous. The inbreeding coefficient = measures the=20 resulting increase in homozygousity. All breeds have a given degree of = homozygosity the mating of two dogs from the same breed would not = produce a=20 recognizable specimen of the breed!=20
Inbreeding increases homozygosity and decrease heterozygosity. So = it can=20 duplicate both desirable and harmful alleles, both of which can be = unsuspected=20 in the line, and may appear. Inbreeding does NOT create anomalies, it = brings=20 present anomalies to the surface. Even when the anomalies are present, = inbreeding might not reveal them. However, once revealed, then the = breeder can=20 do something about them in the next generations of breeding.=20
An increase in harmful recessives is undesirable but it is not a = major=20 drawback if they are identified early. The effect of inbreeding on = major=20 polygenic traits is greater. Generally, traits that are highly = inherited (ie=20 largely additively controlled) are not adversely affected by = inbreeding but,=20 traits under non-additive control, especially those tied to dominance = and thus=20 not of high heritability, are often markedly harmed by inbreeding.=20
Remember that it is difficult to spot unaffected carriers. = When an=20 affected dog shows up, its pedigree is often examined for likely = carriers. For=20 example, PRA is a common problem in many breeds. There are dogs that = come down=20 with PRA that have a certain ancestor in common. That ancestor may = then be=20 considered a possible carrier and line breeding on him is avoided. = This is a=20 simplistic picture, obviously, since it's possible for an unaffected=20 non-carrier of PRA to come from an unaffected carrier that came from = an=20 affected dog (therefore the affected dog is in the unaffected dog's = pedigree).=20 If a general blood test is ever developed that shows the presence of = the=20 recessive in an unaffected dog, then much more accurate breedings may = be done;=20 currently this is only possible for Irish Setters.=20What are like-to-like matings and=20 compensatory matings?=20There is rarely only a single problem a breeder is trying to screen = for.=20 Suppose a suspected carrier of PRA is known for producing excellent = hips. A=20 breeder might therefore introduce that bloodline into theirs for the = hips, and=20 be willing to have the possibility of PRA show up in the line. In = screening=20 out one problem you might have to accept the possibility of another = appearing.=20
Examining the pedigrees also lets you know what percent of ancestry = the=20 dogs share (since the relationships are often much more complex than = simply=20 cousins or aunt/uncle, the degree of common ancestry is often given as = a=20 percentage instead) and decide whether or not it's acceptable given = your=20 current goals.
Like to like mating implies the best to the best and the = worst to=20 the worst where the worst is not used at all. For most breeders, like = to like=20 matings are between dogs which resemble each other greatly and so = similar type=20 dogs are bred. These dogs may or may not be closely related.=20But this is all very vague and = complicated!=20The pups resemble their parents because of the genes in common with = them.=20 If those parents resembled each other their progeny would be even more = like=20 their parents. This tends to make the population look more uniform, = however=20 there is little increase in prepotency from this technique.=20
Compensatory Mating: This unlike to unlike mating is used by = breeders to=20 correct for a defect in an animal by mating it to another animal that = might=20 correct for the defect. The system is basically simple but the breeder = must=20 identify faults and virtues and it requires breed knowledge. The = pedigrees of=20 both dogs should be examined carfully to try to identify the ways in = which the=20 dogs differ and what the expected outcomes could be. A correct dog and = not one=20 who errs in the opposite direction is required. That is, if you want = to=20 improve structure, look for a dog with correct structure and not an = overbuilt=20 dog. This technique often results in only one or two pups with the = combination=20 desired.
Yes, it is. There are no easy answers, and there are = different=20 things to consider in every breed. This uncertainty with respect to = genetic=20 inheritance is exactly the reason that breeding is so difficult to do = right.=20 It helps immensely to have a "mentor", someone who is familiar not = only with=20 the breeds, but the lines your dog belongs to -- advice from such a=20 knowledgeable person is often extremely valuable.=20If we knew everything about genetics, we wouldn't have = problems with=20 our dogs any more. We'd eliminate Hip Dysplasia, PRA, heart problems, = thyroid=20 problems, seizures, etc. within a few generations if we knew = everything.=20 Unfortunately it's an art that few people are actually very good=20 at.
References
"So you want to use your Dog = At Stud?"=20 From the Literary Spot, the newsletter of the Central MD Dalmation Club = 12/89=20 via Retriever Believer, the newsletter of the Labrador Retriever Club of = Southern California 8/91.=20Tucker, Kathy. "Why are you Breeding?", printed in various = newsletters.=20
Whitney, Leon E (DVM). How to Breed Dogs 384 pg. Many case = studies on=20 breeds, breed crosses for dominance studies, Myths and fallacies about = breeding=20 dogs, inheritance of traits (such as temperament, health, intelligence, = and=20 abilities).=20
Wilcox, Bonnie (DVM). "Things to Think about Before Breeding Your = Dog." DVM,=20 printed in various newsletters.=20
Willis, Malcolm B. Practical Genetics for Dog Breeders. = Howell, 1992.=20 228 pgs with appendix for calculations -- several graphs, charts, and = pictures.=20
Willis, Malcolm B. Genetics of the Dog. 417 pgs with breed = specific=20 information on many breeds -- plus several charts and graphs.=20
Breeding Your Dog FAQ