health screening and welfare issues explained

Like begets like; that dogs produce dogs and cats produce cats is universally accepted. We even accept that Dachshunds mated together will produce Dachshunds. However the processes of variation and inheritance are less easily explained and by no means as clear.
Attempting to explain why from a mating between two miniature smooth haired dachshunds it is possible to produce a miniature long haired, or explain how other such “throwbacks” occur in all forms of breeding presented the sort of mystery that baffled such eminent figures as Charles Darwin.
That the results from a mating did not represent a blending of the characteristics of the two parents was self evident. Mating a black animal to a white animal did not produce grey offspring, more pertinent to us is that mating a too long dachshund to a too short one does not produce dachshunds of correct length.
That enigma was finally solved by Gregor Mendel (1865). His careful and well recorded experiments led him to formulate his Laws of Inheritance and conclude that each Gamete (i.e.sex cell, e.g. sperm or ova) carried a germinal unit (now labelled an Allele) that after fertilisation the resulting pair of alleles, one from each parent constitute a GENE which would create a specific characteristic in the offspring and would not themselves be changed.
We now recognise that these Alleles, one from each parent, may be dissimilar and thus both not appear in the next generation, the one appearing being called Dominant and the one not appearing, Recessive. However the recessive one remains unaltered to be passed on via a gamete to the next generation and should two recessives come together in a future mating the recessive characteristic, will reappear. This explains why a miniature smooth haired dachshund can be born to two miniature wire haired dachshunds and a miniature long haired dachshund born to two min smooth haired parents.
There are many fascinating complications to this simple, single gene, Dominant/Recessive mode of inheritance. There are cases where the dominance is incomplete, red antirrhinums crossed with white ones will yield pink antirrhinums, similarly, in live stock, we get roan cattle. Life becomes more complicated when more than one characteristic is considered and many complex characteristics are controlled not by one single gene but by a number of interacting genes.
You may be pleased to know that such complications, fascinating though they may be to the scientifically minded, are not essential knowledge for the serious and concerned breeder of miniature smooth haired dachshunds. The only complication we need to know is that as the gene has to be copied time and time again throughout the development of an individual and in the production of sperm and ova. With such multiple transcriptions occasional mistakes occur causing a change or Mutation in the gene.
At some stage such a mutation has happened in miniature smooth haired dachshunds, the relevant mutation, presently under consideration being labelled the cord1 mutation.
In their incomplete and inconclusive research, the Animal Health Trust (AHT) did find the presence of the cord1 mutated gene in many of the admittedly small sample of miniature smooth haired dachshunds whose DNA was analysed. Unfortunately with such a small and unrepresentative sample it was not possible to determine how prevalent it is throughout the population of miniature smooth haired dachshunds in the UK. As it does not appear to have a direct survival value, and has been in existence for many years, the probability is that it is widely and randomly distributed.
Although the present AHT’s research does not provide any compelling evidence of the cord1 mutation per se causing any disease or defect, one unfortunate valid statistic is that the vast majority of mutations are harmful. As serious and concerned breeders we should therefore take sensible steps to reduce the incidence of the cord1 mutation in the population but to do this in such a way as not deplete the gene pool.
Points to bear in mind include;

No dogs or bitches should be discarded from the breeding population on the basis of their cord1 mutation status.
No stud dog should be selected solely on a basis of its cord1 mutation status. In selecting a stud dog, only once the usual factors such as temperament, conformation, pedigree, health etc. have been considered should the cord1 status be considered

Finally; if you are not scientifically inclined, are confused by genetics and feeling lost then ask advice. The Smooth Haired Dachshund Club, the providers of this information pack have appointed a consultant to offer advice. Such advice will not attempt to say which stud dog you should use but will offer advice as to the possible outcomes of using dogs of differing cord1 statuses and, should you so wish, attempt to clarify the genetics that may be confounding you.


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INTRODUCTION TO HEREDITARY Like begets like; that dogs produce dogs and cats produce cats is universally accepted. We even accept that Dachshunds mated together will produce Dachshunds. However the processes of variation and inheritance are less easily explained and by no means as clear. Attempting to explain why from a mating between two miniature smooth haired dachshunds it is possible to produce a miniature long haired, or explain how other such “throwbacks” occur in all forms of breeding presented the sort of mystery that baffled such eminent figures as Charles Darwin. That the results from a mating did not represent a blending of the characteristics of the two parents was self evident. Mating a black animal to a white animal did not produce grey offspring, more pertinent to us is that mating a too long dachshund to a too short one does not produce dachshunds of correct length. That enigma was finally solved by Gregor Mendel (1865). His careful and well recorded experiments led him to formulate his Laws of Inheritance and conclude that each Gamete (i.e.sex cell, e.g. sperm or ova) carried a germinal unit (now labelled an Allele) that after fertilisation the resulting pair of alleles, one from each parent constitute a GENE which would create a specific characteristic in the offspring and would not themselves be changed. We now recognise that these Alleles, one from each parent, may be dissimilar and thus both not appear in the next generation, the one appearing being called Dominant and the one not appearing, Recessive. However the recessive one remains unaltered to be passed on via a gamete to the next generation and should two recessives come together in a future mating the recessive characteristic, will reappear. This explains why a miniature smooth haired dachshund can be born to two miniature wire haired dachshunds and a miniature long haired dachshund born to two min smooth haired parents. There are many fascinating complications to this simple, single gene, Dominant/Recessive mode of inheritance. There are cases where the dominance is incomplete, red antirrhinums crossed with white ones will yield pink antirrhinums, similarly, in live stock, we get roan cattle. Life becomes more complicated when more than one characteristic is considered and many complex characteristics are controlled not by one single gene but by a number of interacting genes. You may be pleased to know that such complications, fascinating though they may be to the scientifically minded, are not essential knowledge for the serious and concerned breeder of miniature smooth haired dachshunds. The only complication we need to know is that as the gene has to be copied time and time again throughout the development of an individual and in the production of sperm and ova. With such multiple transcriptions occasional mistakes occur causing a change or Mutation in the gene. At some stage such a mutation has happened in miniature smooth haired dachshunds, the relevant mutation, presently under consideration being labelled the cord1 mutation. In their incomplete and inconclusive research, the Animal Health Trust (AHT) did find the presence of the cord1 mutated gene in many of the admittedly small sample of miniature smooth haired dachshunds whose DNA was analysed. Unfortunately with such a small and unrepresentative sample it was not possible to determine how prevalent it is throughout the population of miniature smooth haired dachshunds in the UK. As it does not appear to have a direct survival value, and has been in existence for many years, the probability is that it is widely and randomly distributed. Although the present AHT’s research does not provide any compelling evidence of the cord1 mutation per se causing any disease or defect, one unfortunate valid statistic is that the vast majority of mutations are harmful. As serious and concerned breeders we should therefore take sensible steps to reduce the incidence of the cord1 mutation in the population but to do this in such a way as not deplete the gene pool. Points to bear in mind include; No dogs or bitches should be discarded from the breeding population on the basis of their cord1 mutation status. No stud dog should be selected solely on a basis of its cord1 mutation status. In selecting a stud dog, only once the usual factors such as temperament, conformation, pedigree, health etc. have been considered should the cord1 status be considered Finally; if you are not scientifically inclined, are confused by genetics and feeling lost then ask advice. The Smooth Haired Dachshund Club, the providers of this information pack have appointed a consultant to offer advice. Such advice will not attempt to say which stud dog you should use but will offer advice as to the possible outcomes of using dogs of differing cord1 statuses and, should you so wish, attempt to clarify the genetics that may be confounding you.	NOTIFY OR REQUEST INFORMATION - click the links NOTIFICATION OF THE CORD 1 STATUS OF A STUD DOG REQUEST FOR THE NAMES OF SUITABLE, MINIATURE SMOOTH HAIRED DACHSHUND, CORD1 STATUS STUD DOGS UNDERSTAND GENETICS The cell is the basic building block of the body. In the cell is the NUCLEUS containing the chromosomes, these carry the GENES that pass on the characteristics from one generation to the next. Genes are found as a pair, known as ALLELES, one of which is inherited from each of the parents. If the alleles are identical the individual is said to be HOMOZYGOUS for the character determined by the gene. If the alleles differ it is said to be HETEROZYGOUS for that character. 1.Thus an individual carrying two of the mutated cord1 alleles is said to be Homozygous for the cord1 mutated gene. In their research and on their certificates AHT label these as AFFECTED 2. An individual carrying only one mutated cord1 allele is said to be Heterozygous for the cord1 mutated gene. In their research and on their certificates AHT label these as CARRIERS 3. An individual carrying two non mutated alleles is said to be Homozygous for the normal (un-mutated) Gene. In their research and on their certificates AHT label these as CLEAR In the formation of Sperm and Eggs for sexual reproduction the pairs are separated. For the individual homozygous for the cord1mutated gene (AFFECTED) all of the sperm or eggs can only contain the mutated allele. For the Heterozygous individual (CARRIERS) half of the sperm or eggs will carry the mutated allele, the other half will contain the normal (un-mutated) allele. For the individual Homozygous for the non-mutated allele ( CLEAR) all of the sperm or eggs can only contain the non-mutated allele. At present there is no compelling evidence that the cord1 mutation is a direct cause of any disease or defect in Miniature Smooth Haired Dachshunds. However, as the majority of mutations are harmful, it behoves us all as responsible breeders to plan future breeding programmes in such a way as to minimise and finally eradicate the cord1 mutation from our breed BREEDING STRATEGIES Points to remember No Dog or bitch should be discarded from the breeding population on account of its cord1 status No stud dog should be selected solely by its cord1 status The normal criteria should be used in selecting a suitable stud dog to be used and only when the criteria such as conformation, temperament, health and pedigree fit have been met should the cord1 status be considered To reduce the incidence of the cord1 mutation it is essential to know the cord1 status of the bitch, the second is to know the cord1 status of the dog. The cord1 status of your bitch can be determined by DNA analysis; the status of the majority of dogs at stud is listed in the records held by the current Smooth Haired Club’s consultant on the issue. Knowing the relevant cord1 statuses the probable outcome of the mating in question can be assessed. EXPLAINED FURTHER BREEDING STRATEGIES - click the link
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