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HIPS/ELBOWS & DNA
(PHOTO: 17 week old TAPUA SEARCH THE VALLEY - ERROL & TAPUA SEARCH THE STUDY - FLYNN)
DISCLAIMERThe breeding priorities and culling policies stated in this section apply only to dogs owned or bred by TAPUA KENNELS.We do not assume nor expect any individual, breeder or show person to agree with or accept our agendas regarding the care, training, breeding or nutrition of Labrador Retrievers nor any other breed._______________________________________
DNA, HIP & ELBOW RESULTS OF LABRADORS OWNED OR BRED BY TAPUA KENNELS
NAME M/F D.O.B. Hips Elbows EIC/PRCD COLOUR TAPUA SEARCH IN THE VALLEY M 01/09/11 TBA TBA CLEAR BLACK (+Y) TAPUA SEARCH THE STUDY M 01/09/11 TBA TBA CLEAR BLACK (+ Y) TAPUA HEENI Te ANNA F 11/09/10 H 1:3 E 0:0 CLEAR BLACK (+y/c) TAPUA CELTIC CHARM F 04/03/11 TBA TBA CLEAR YELLOW INVERGOWIE LARA F 21/11/08 H 4:5 E 0:0 CLEAR YELLOW ELLOESSE I SEE RED F 05/10/2011 TBA TBA CLEAR YELLOW
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GENETIC MODES OF INHERITANCE
Genetics and genetic testing are the buzz concepts in dog breeding today. Terms get thrown around that are often confussing and easily misinterpreted. The following is an effort to clarify some of the genetic concepts. The challenge for a responsible breeder is to determine whether or not there are genetic issues in their lines. . Many breeders struggle to determine whether a defect or disease is hereditory. Because MANY disorders in dogs do not, as yet, have a causal genetic marker identified, breeders are the first to recognise the occurrence of defects or disease in their lines from what they create in their own kennels. Honesty, diligence and accurate record keeping is vital. It is easy to blame the inherited abnormal genes of the dog or bitch you have used or bred from as the previous breeders 'fault' - it is what you do with the progeny of what you have chosen to create in the litter which matters.
This is a three step method that should alert breeders that a genetic condition may exist in their lines.
1: The condition occurs more often among dogs that are related. 2: The condition increases in frequency with inbreeding. 3: The disease occurs usually at the same age for most affected animals.
There are three modes of inheritance for genetic disease and disorder:- single genes, multiple genes & chromosomal anomolies
Single Genes This is where one gene acts on its own to affect an offspring, the disease or defect is said to be caused by a single abnormal gene. There are three methods by which a single gene can cause disease or a defect. Recessive inheritance, dominant inheritance or X-linked method. (C.L.Battaglia PHD. 1995)
Recessive Inheritance Both parents carry a disease or disorder on 1 abnormal gene. Although the parents themselves do not express this condition. For a pup to become affected by the recessive gene the pup must inherit both abnormal genes from each of the contributing carrier parents. If the pup inherits only one abnormal gene from a carrier parent then the condition perpetuates within the lines unexpressed until it is bred with another carrier and the abnormal condtion is expressed in the progeny. The primary benefit of genetic testing is to identify carrier sires and dams prior to mating. Therefore the breeder can make an informed decission about the mating. Carriers do not necessarily need to be excluded from a breeding program however the progeny will need to be tested and clear progeny identified if the breeder chooses to eliminate the conditon from their lines.
PARENTS GENOTYPE SIBLINGS GENOTYPE CLEAR x CLEAR = 100% CLEAR CLEAR x CARRIER = 50% CLEAR 50% CARRIER CLEAR x AFFECTED = 100% CARRIER CARRIER x CARRIER = 25% CLEAR, 50% CARRIER, 25% AFFECTED CARRIER x AFFECTED = 50% CARRIER, 50% AFFECTED
Dominant Inheritance In this case only one parent need to have an abnormal gene in order to affect the pups and to transmit the disease of defect from one generation to the next. Severity of the condition will vary from extreme to mild. There is a myth perpetuated by some breeders that there is a 'killer gene' which will kill the affected pup in utero or at birth and therefore the other pups will not be affected. This is obvioulsy false or else dominant inheritance would not occur. Expression of the condition at birth can be very mild and not cause any problems till later in life. Such as congenital lymphedema in GSD's. X- linked Inheritance The defective genes are located on the X chromosome. In dogs, as in all mammals the female of the species has two X chromosomes and the male has an XY. All male pups recieve the Y chomosome from the sire and the X from the dam. Because the Y chromosome determines the maleness of a dog the sire determines the sex of the offspring and the maleness characteristics. The X chromosome contains a large number of genes which determine a number of functions. Regarding X- linked recessive diseases the affected pups are nearly always male, who have recieved the affected gene from their mother. As is seen in the blood clotting disease Hemophelia - causing death if left untreated with clotting factors.
Multiple Genes This is when more than one pair of genes interact to cause a disease or defect. The genetic cause is called polygenetic. A classic and problematic example of this is Hip Dysplasia. It has been noted since the 1950's that progeny from normal parents could be displastic and it has been noted that parents with dysplasia when mated to non dyplastic parent produced a high number of dysplastic progeny. Whilst this suggested a dominant gene it was discovered in Sweden on GSD's that displasia is not causeded by single cell recessive or dominant gene methods as discussed. HD is a condition caused by by the culminative effects of a number of genes (polygenetic) which affect the developement of the hip joint. Polygenetic diseases are susceptible to modification by the environment. Puppies of larger breeds should not be allowed to become excessively heavey since this directly effects the develoment of HD. The occurance of HD is greatest amongst dogs who show rapid growth and weight gain in their puppy/youth age. The incident increases further in puppies that are overweight in their first 8 weeks of life.
Chromosomal Anomalies These condition affect the XY chromosome of the male dogs. Normal dogs have 78 chromosomes,they randomly inherit 39 pairs of chomosomes from their parents and the parents ancestors which include XY for the males and XX for females. In rare cases the nmormal male inherits and extra X chromosome and become XXY. When this occurs the affected male will have abnormally small testes and will be sterile. Chromosomal abnormalities are also said to account for utero deaths and malformed pups.
For further reading on the impact of genetic disease I recommend 'Breeding For Better Dogs' Carmelo L. Battaglia PHD 5th Edition 1995. ____________________________________________________ COAT COLOUR
There are only 3 colours in the Labrador Retrievers and every breeder likes to be able to predict the coat colour of their dogs with reasonable accuracey I have found the following website to be very usefull.
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SERVICE DOGS & THE LABRADOR RETRIEVER
Labradors are well known for their suitability as guide dogs, explosive detection and sniffer dogs for Customs and Police as well as the much loved and valued family companions. We focus on the neurological stimulation of pups in early developement and they are raised in an environment which is rich in stimulation and safe for the puppies. This is to enhance their tractability and their resilience which makes them more suitable as service dogs and companion dog. If you have any questions about our breeding and training practices please feel free to contact us for more information. ________________________________________
HEALTH PRIORITIES FOR THE BITCH AND CRITERION FOR EXCLUSSION FROM BREEDING
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HEALTH PRIORITIES OF THE STUD DOG
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HEALTH OF THE PUPPIES ALL TAPUA PUPPIES WILL BE SOLD UNDER MDBA CONTRACT AND ON LIMIT REGISTER MAIN REGISTER PUPS ARE AVAILABLE ONLY WITH PRIOR APPROVAL
No gaurentee will be given regarding show ring worthiness due to the many variables involved in creating a successful show dog
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Pauline Gill & Peter Levett Woodstock, NSW, Australia Phone : PH:(02) 6345 0027 MB: 0429399341 Email : tapua@bigpond.com |
