Breeding means the selective mating of animals of a species with the aim to preserve the quality of the respective race and to improve the characteristics. This must never occur at the expense of animal health. For each pedigree cat there is a required standard in the cat associations striven for by selective matings.
Therefore, in animal breeding various breeding methods are applied:
*Inbreeding
*Linebreeding
*Pure breeding (other terms: external breeding, attribute breeding)
*Outcross breeding
Definition: Under inbreeding we shall generally understand the mating of comparatively near relatives. This means for example mating of siblings and inbreeding with mother and son or father and daughter. Inbreeding enhances the homozygosity.
ADVANTAGES
*Desired characteristics / desired genes are yielded quickly and deliberately, solidified and strengthened.
*Demonstrably, inbreeded animals transfer their type additionally to their offspring.
*Defects, already existing latently in the genome, are revealed by splitting up the recessive genes.
*Development of homogeneous types
DISADVANTAGES
*Undesired genes are also solidified and strengthened.
*Reduction of diversity and decrease of heterozygous features
*Health? Inbreeding depression?
There are hardly any studies about the outcomes of inbreeding in cat breeding. For evaluation we have to rely on studies about other races.
There are reports about lions and the effects of inbreeding on the stock of the pack. These big cats live in Tanzania in the caldera of Ngorongoro and they are nearly completely cut off from the outside world due to the position of their hunting ground (caldera of an extinct volcano). There is hardly any immigration of new animals or „fresh blood “. The last lion immigrated twenty years ago bringing along fresh genetic material. Nowadays around 50 lions live in the caldera of Ngorongoro but they can only reproduce among each other and nearly all of them descend from a few males. This inbreeding and the thereto relating genetic poverty cause severe problems. Scientists discovered that most males produce malformed spermatozoa leading to problems with reproduction. But. also the immune system of many lions in the caldera of Ngorongoro is weakened by inbreeding and the animals become vulnerable for infectious diseases like distemper The situation turned extremely bad in 2000 when the stock of the lion pack within a few month decreased from 67 animals to 41.Cause: an unnatural accumulation of diseases.
Source:
http://www.scinexx.de/dossier-detail-276-10.html [state of 18.11.2005]
TV: The quiet death of the lions, planet e. 31.1.2016
With several horse breeds undesired effects of increasing consanguinity could already be shown concerning fecundity features, size and hinge aberration. With increasing inbreeding conduct disorders are reported, especially of deranged maternal instinct. For gene locus, influencing features as vitality, fertility and growth it generally seems to be more favourable not being occupied with identic genes. In relationship studies for example with Western Horses a connection of increased linebreeding with preferred transmitters and reduced bone growth (overbite) and joint damage could be detected.
http://www.barnboox.de/wissensdatenbank/fachartikel/linienzucht-bei-pferden-chancen-und-risiken
Definition: Linebreeding is a combination of inbreeding and pure breeding. In linebreeding cats of a race with similar characteristics are mated.
At most species linebreeding with an inbreeding coefficient up from 12.5 %, 9,25 %, 6,25 % or less was made a common practice. Often is applied to detect a certain gene feature, for example colour or a genetic defect. Again, it is important that constantly fresh blood comes into the lines, otherwise the genepool dwindles on and on.
ADVANTAGES
*Easier retracing of genes (e.g. for colour breeding)
*Faster success in developing colour or shape
*Thinning out of undesired genes and heredity of undesired characteristics
*Discovery of pathological genes
*Breeding of an individual line with particular characteristics
DISADVANTAGES
*Genetic impoverishment, therefor weakening of the immune system
*Pathological genes are strengthened and thus diseases are supported
*Quicker occurrence of new mutations (at some point animals with defects)
Definition: Pure breeding is known as extrinsic breeding within a race. The race thus survives.
As extrinsic breeding here, we describe; mating of cats of the same race, not being related. It is not a mating of different cat breeds!
With pure breeding external characteristic as well as predispositions for desired utilisation properties shall be reliably passed to the offspring and the present gene pool shall be preserved and improved.
ADVANTAGES
*Pure breeding lays the foundation for the preservation and the increase of breed specific characteristics
*Breed untypical characteristics are avoided
*Cats are highly vital and resilient, cats have hardly any defects
DISADVANTAGES
*The outcome may be disappointing, recessive features can be invisibly passed on
*The degree of character formation is not as easily predictable as with
*Solidification of desired characteristics takes more time
Example:
Mating of ARJUNA Magia Vostoka of Magic Thai Goblin (left side) und GAIYA Yeux d´Outremer of Magic Thai Goblin (right side)- both Thai cats are not related. Gaiya originates from French breeding lines, Arjuna from Russian lines.
Definition: Outcross is the mating of different breeds. The outcome of this breed is called hybrid. Many breeds can be tracked to outcross (e.g. Tonkinese cat = Burmese x Siamese; Leopard cat = Asian Leopard cat x Domestic cat)
There are multifarious reasons for outcross.
*Occurrence of a new breed
*Improvement of already existing colours
*Insertion of new colours (or other features) into an existing breed
Outcross may only take place with prior permission of a cat association -and club. Before starting, for this purpose, a breeding plan has to be developed and submitted. After four generations the offspring will be accepted as purebred by the associations.
In accordance with the breed standard outcross is allowed for some breeds
For Exotic, e.g., outcross with Persian cat is allowed, in contrast, for Persian cat outcross with Exotic is not allowed. That fact can cause that long-haired pups given birth by an Exotic [if the gene is carried recessively y both parents], are not registered as Persian cat. This applies also for outcross between Abyssinian cat und Somali cat. Abyssinian cat must have no Somali cat in the pedigree, for Somali cat outcross with Abyssinian car is allowed.
Since the mating of Siamese und Oriental Shorthair is allowed both breeds may fall in each litter.
Picture: Oriental Shorthair litter with 1 OSH und 2 Siamese
ADVANTAGES
*Genetic possible improvements
*Breeding of new races
*Bringing new colours into the breed
DISADVANTAGES
*in the early generations loss of the breeds renowned characteristics; with "outcrosses" some of the desired features (e.g. eye – or/and fur colour- or type) often get lost, whereas other wanted characteristics (e.g. stronger physique, a more vital constitution, disposition for a certain colour) come anlong.
*Diseases, typical for the crossbred races may occur, recessively passed on.
Example: Occurrence of a new race
In 1964 in the USA a breeding programme started with the aim to receive a cat with oriental type and the red brown fur of the Abyssinian cat. Mating a Chocolate Point Siamese male cat with an Abyssinian cat did not bring agouti-kittens, in fact, a cinnamon spotted one with ivory ground stood out. The mating was repeated, thereby the actual breeding programme started. To receive a larger stature and to increase the variety of colours American Shorthair was crossbred. Already in 1966, the CFA registered the kittens, but it should take another two decades until the Ocicat took the shape the way we know it today. The first purebred specimens reached Europe in 1991 and were acclaimed by FIFe in 1992 in Budapest.
Source:
Example: Insertion of new colours
To bring in the agouti gene into the Birman cat breed a Persian Chinchilla was mated with a Birman male cat. The thus created hybrids again were mated with Birman cats, so that the phenotype (appearance) and the genotype of the offspring of later generations again were adapted to the standard of the Birman cat. The desired agouti-gene thus survived in Birman breed.
Source: Claudia Ricken, Genetik für Pointkatzenzüchter, S. 248
The colour cinnamon was achieved in the Oriental Shorthair breed by crossbreeding sorrel Abyssinian cats in the 60s.
Source: www.entenere.de/index-deutsch.htm
Example: Insertion of new colours into Siamese breed
The insertion of tabby and red into the Siamese breed also took place by using outcross.
Serious attempts of breeding tabbies started in 1960 independently by two different breeders by crossbreeding striped European Shorthair cats.
Source: www.tpscs.co.uk/history.html
Two focused Siamese-breed programmes for red lines started in the 40s in the USA and the UK (later also in Belgium and the Netherlands).
The colour occurred in Great Britain by outcross with another race (a red European Shorthair male cat). In the litter was a tortoise shell half Siamese cat, which gave birth to redpoint kitten after being mated with a seal point full Siamese male cat.
Picture: Somerville Scarlet Pimpernel („Robber“) and Somerville Harlequina with Kitten Golden Miranda and Golden Seal
SOURCES:
http://sayrevolution.org/SiameseCatsBreeders/siamese-kittens-tortie-point
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Claudia Ricken, Genetik für Pointkatzenzüchter,2005, S. 234ff
https://de.wikipedia.org/wiki/Zucht
www.bauernhof.net/zuchtmethoden/
Sandra Storch: Vererbtes Design: Zucht, Genetik, Gesundheit und Farben der Katze. Books on Demand, 2006
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