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This is an old revision of this page, as edited by Eek111 (talk | contribs) at 07:56, 30 March 2018 (Added the Dog breeding page draft in. Added Terminology and Estrus cycle sections. Moved a paragraph from History to a new Breeding Purebreds section. Edited and deleted misc sentences.). The present address (URL) is a permanent link to this revision, which may differ significantly from the current revision.

A litter of puppies and their mother

Dog breeding is the practice of mating selected dogs with the intent to maintain or produce specific qualities and characteristics. When dogs reproduce without such human intervention, their offsprings' characteristics are determined by natural selection, while "dog breeding" refers specifically to the artificial selection of dogs, in which dogs are intentionally bred by their owners.[1]

Terminology

The female parent, a bitch, of puppies is referred to as the dam and the male parent, a stud, is referred to as the sire. A litter is those puppies born from the same pregnancy. A whelp is a newborn puppy and giving birth in dogs is called whelping. Dogs commonly give birth in a whelping box, a simple box or pen provided to the dam to help shelter and contain the puppies.

A person who intentionally mates dogs to produce puppies is referred to as a dog breeder. Line breeding is the planned breeding of dogs with their relatives. This is done to strengthen the appearance of specific desired traits in offspring. Line breeding is differentiated from inbreeding by excluding pairings between parents and offspring, and between full siblings. Outcrossing is the planned breeding between two unrelated dogs, used to increase genetic diversity in a breed and decrease genetic issues or abnormalities inherited from line breeding or inbreeding.

Estrus cycle

Dogs reach puberty between 6-24 months old. Female dogs will start having an estrus (also spelled "estrous") cycle. A dog in estrus, also known as being "in heat", can become pregnant during this 3-21 day period.[2] There are 4 stages to the estrus cycle in dogs:

  • Anestrus: 60 to 200 days long. During this time the uterine lining repairs itself from the estrus and diestus periods.
  • Proestrus: 3-17 days long. The follicle secretes estrogen and there may be some discharge from the vulva.
  • Estrus: 3-21 days long. Vulva discharge changes to a reddish or dark brown color.
  • Diestrus: 60-100 days long.

Breeding and gestation

History of dog breeding

  • Few hours old
    Few hours old
  • Three days old
    Three days old
  • Few weeks old
    Few weeks old
  • Seven weeks old
    Seven weeks old
  • Twelve weeks old
    Twelve weeks old

Humans have maintained populations of useful animals around their places of habitat since pre-historic times.[3] Artificial selection in dog breeding has influenced behavior, shape, and size of dogs.[4] Humans have intentionally bred together dogs with certain characteristics to produce offspring better at specific tasks or with certain temperaments. Through this process, hundreds of dog breeds have been developed.Over millennia, domesticated dogs have developed into distinct types, or groups, such as livestock guardian dogs, hunting dogs, and sighthounds.

Some researchers believe that the evolution of dogs from wolves is an example of neoteny or paedomorphism selection, that results in a retention of juvenile physical characteristics. Compared to wolves, many adult dog breeds retain such juvenile characteristics as soft fuzzy fur, round torsos, large heads and eyes, ears that hang down rather than stand erect, etc.; characteristics which are shared by most juvenile mammals, and therefore generally elicit some degree of protective and nurturing behavior cross-species from most adult mammals, including humans, who term such characteristics "cute" or "appealing". It has been seen that these traits can even prompt an adult female wolf to act more defensively of dog puppies than of wolf puppies.[5] The example of canine neoteny goes even further, in that the various dog breeds are differently neotenized according to the type of behavior that was selected.[6] Other researchers believe that because this comparison is based on the gray wolf, which is not the ancestor of the dog, that this comparison is invalid.[7] Further research indicates that the concept of neoteny as a means of distinguishing dogs from wolves is baseless.[8]

Breeding purebred dogs

See also: Purebred dog

Initially, the ownership of working and purebred dogs was a privilege of the wealthy. Nowadays, many people can afford to buy a dog. Breeders of purebred dogs can register the birth of a litter of puppies to a dog registry associated with a kennel club to record the parentage of the litter in stud books. Such registries maintain records of dogs’ lineage and are usually affiliated with kennel clubs like the AKC (American Kennel Club).[9] Maintaining correct data is important for purebred dog breeding. Access to records allows a breeder to analyze the pedigrees and anticipate traits and behaviors that may be passed onto offspring. Requirements for the breeding of registered purebreds vary between breeds, countries, kennel clubs and registries. Breeders also have to abide by an organization's rules to participate in its breed maintenance and development programs. The rules may apply to the health of the dogs, such as joint x-rays, hip certifications, and eye examinations; to working qualities, such as passing a special test or achieving at a trial; to general conformation, such as evaluation of a dog by a breed expert. However, many registries, particularly those in North America, are not policing agencies that exclude dogs of poor quality or health. Their main function is simply to register puppies born of parents who are themselves registered.[10][11][12]

Criticism

Some dogs have certain inheritable characteristics that can develop into a disability or disease. Inbreeding and line breeding decrease the genetic diversity of offspring and increase the risk of inheriting and developing health issues. Canine hip dysplasia is one such condition. Some eye abnormalities, some heart conditions, and some cases of deafness have been proven to be inherited.[13] There have been extensive studies of these conditions,[14] commonly sponsored by breed clubs and dog registries, while specialised breed clubs provide information of common genetic defects for their breeds. As well, special organizations, such as Orthopedic Foundation for Animals, collect data and provide it to breeders, as well as to the general public. Conditions such as hip dysplasia can impact some breeds more than others.[15]

Some registries, such as American Kennel Club, may include a record of the absence of certain genetic defects, known as a certification, in an individual dog’s record. For example, the German Shepherd Dog national breed club in Germany is a registry that recognizes that hip dysplasia is a genetic defect for dogs of this breed. Accordingly, it requires all dogs to pass evaluation for absence of hip dysplasia to register their progeny, and records the results in individual dog‘s pedigrees.

There are BBC documentaries titled "Pedigree Dogs Exposed" and "Pedigree Dogs Exposed – Three Years On" that claim health problems in dogs from inbreeding. Problems such as breathing in the Pug breed and Pekingese breed, spinal problems in the Dachshund breed, and Syringomyelia in the Cavalier King Charles Spaniel breed. It has been concluded that "findings imply that when selective breeding was done by humans, it squashed the snouts of certain dog breeds, it also morphed their brains".[16]

Some scientific researchers argue that advances in artificial reproduction technology for the purposes of dog breeding can be helpful but also have "detrimental impacts" when overused instead of natural selection principles. These scientists call for a deeper understanding of natural selection, leading to a more naturalistic approach in dog breeding.[17]

Inbreeding depression

Inbreeding depression is the reduced survival and fertility of offspring of related individuals.[18] A study of 42,855 dachshund litters found that as the inbreeding coefficient increased, litter size decreased and the percentage of stillborn puppies increased, thus indicating inbreeding depression.[19]

  1. ^ Seranne, Ann (1980). The Joy of Breeding Your Own Show Dog. New York, N.Y: Howell Book House. ISBN 0-87605-413-0.
  2. ^ Eilts, Bruce E (25 September 2012). "The Normal Canine Estrous Cycle". therio.vetmed.lsu.edu. Retrieved 2018-03-28. {{cite web}}: Cite has empty unknown parameter: |dead-url= (help)
  3. ^ Darwin, Charles (2004). The Variation of Animals And Plants Under Domestication. Kessinger Publishing. ISBN 1-4191-8660-4.
  4. ^ Akey, Joshua M.; Ruhe, Alison L.; Akey, Dayna T.; Wong, Aaron K.; Connelly, Caitlin F.; Madeoy, Jennifer; Nicholas, Thomas J.; Neffb, Mark W. (January 19, 2010). "Tracking footprints of artificial selection in the dog genome". Proc Natl Acad Sci U S A. 107 (3): 1160–5. doi:10.1073/pnas.0909918107. PMC 2824266. PMID 20080661.
  5. ^ Frank H; Frank MG (1982). "On the effects of domestication on canine social development and behavior". Applied Animal Ethology. 8 (6): 507–525. doi:10.1016/0304-3762(82)90215-2.
  6. ^ Gould, Stephen Jay (1993). Eight Little Piggies: Reflections in Natural History. New York: W. W. Norton & Company. p. 934. ISBN 0-393-31139-2. {{cite book}}: Invalid |ref=harv (help)
  7. ^ Koler-Matznick, Janice (2002). "The origin of the dog revisited". Anthrozoös: A Multidisciplinary Journal of the Interactions of People and Animals. 15 (2): 98. doi:10.2752/089279302786992595.
  8. ^ Drake, Abby Grace; Coquerelle, Michael; Colombeau, Guillaume (2015). "3D morphometric analysis of fossil canid skulls contradicts the suggested domestication of dogs during the late Paleolithic". Scientific Reports. 5: 8299. doi:10.1038/srep08299. PMID 25654325.
  9. ^ American Kennel club Staff (1997). The complete dog book. New York, N.Y: Howell Book House. ISBN 0-87605-047-X.
  10. ^ "German Shepherd Dog Dog Breed Information, Pictures, Characteristics & Facts". Dogtime.com. Retrieved 2014-08-03.
  11. ^ "Designer Disaster! Is Dog Breeding Contributing to More Unhealthy and Homeless Dogs?". Archived from the original on 2013-12-12.
  12. ^ "The Truth About Purebred Dogs Will Absolutely Disgust You". Viralnova.com. 2013-12-07. Archived from the original on 2013-12-20. Retrieved 2014-08-03. {{cite web}}: Unknown parameter |deadurl= ignored (|url-status= suggested) (help)
  13. ^ George A. Padgett (1998). Control of Canine Genetic Diseases (Howell Reference Books). New York, N.Y: Howell Book House. ISBN 0-87605-004-6.
  14. ^ "Diseases by Breed". Research.vet.upenn.edu. Retrieved 2014-08-03.
  15. ^ "Hip Dysplasia by Breed". Orthopedic Foundation for Animals. 2010. Retrieved 3 August 2014.
  16. ^ Jabr, Ferris. "Changing Minds: Has Selective Breeding Restructured Some Dog Brains?" Scientific American Global RSS. N.p., 13 Aug. 2010. Web. 10 Nov. 2014.
  17. ^ Vandeloo, John (2009). "Journal of Veterinary Behavior: Clinical Applications and Research Volume 4, Issue 6, November–December 2009, Pages 245 Cover image The importance of intergrating [sic] natural selection within a detector dog selective breeding model". Journal of Veterinary Behavior: Clinical Applications and Research. 4 (6).
  18. ^ Charlesworth D, Willis JH (2009). "The genetics of inbreeding depression". Nat. Rev. Genet. 10 (11): 783–96. doi:10.1038/nrg2664. PMID 19834483.
  19. ^ Gresky C, Hamann H, Distl O (2005). "[Influence of inbreeding on litter size and the proportion of stillborn puppies in dachshunds]". Berl. Munch. Tierarztl. Wochenschr. (in German). 118 (3–4): 134–9. PMID 15803761.
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