Extended project on the Subject of Genetic Diseases In Cocker Spaniels

EXTENDED PROJECT:

Are genetic diseases, caused by selective breeding, a problem in English Cocker Spaniels and how can this problem be addressed?

Man has long had a relationship with the dog and many biologists believe that this began with the Canis Lupus (The Grey Wolf) (a1). After they realised the advantages that this animal could bring to their hunting and gathering, they attempted to tame the wolf. Domestication had begun, as man would only breed from the wolves which had specific traits required for their way of living.
As the number of humans increased the variation of different wolves, in different tribes of men would have become more pronounced with each group requiring a wolf with different traits, such as coat colour, swimming ability or even size, reflecting their environments.
Over time man developed a group of dogs, which included dogs such as the cocker spaniel, which were bred to follow the scent of their quarry over long distances. With traits involving a long nose, to ensure that scents could be accurately followed.
Many consider the ears to be important for the function of cockers as gun, and trail dogs, however this is not the case. The breed standards, set by the kennel Club, state that a show cocker should have ears, which are “Lobular, set low on a level with eyes. Fine leathers extending to nose tip. Well clothed with long, straight silky hair”(a2) Whereas, the breed standards for the working cocker, which is registered as the same breed, have ears, which do not hang as low as those of the show cocker. This is because, although long ears are selected in the show ring, they are considered to be an impediment in the field (a3). This therefore highlights that the characteristics of ears are not important to help concentrate a scent, and that this particular characteristic is selected for appearance and not function as is often thought.

As long as man has required dogs for specific jobs, ‘designer’ dogs have been bred to carry out these specific tasks. This has meant that dogs have suffered years of inbreeding and have therefore suffered from a limited gene pool, so that genetic diseases are directly passed down through the generations. Ultimately becoming more of a problem.


A genetic disorder is a disease in which an abnormality in the genetic makeup of the dog contributes greatly towards causing the condition or increasing the risk of getting the condition. (b1)
(Appendix 2: See for basic genetics, genes and alleles)


Cocker spaniels are themselves prone to a large number of harmful and potentially fatal genetic diseases.
One of these is Canine Phosphofructokinase deficiency (PFK). This is an autosomal recessive genetic disease, which is a genetic condition that appears only in individuals who have received two copies of an autosomal (non-sex) gene, one copy from each parent, who do not display the disease, as they are simply carriers with one copy of the gene. (c1)
If both parents are carriers, there is a 25% chance of a puppy inheriting both abnormal genes and, consequently, developing Canine Phosphofructokinase.
This disease prevents the metabolism of glucose, from its polymers, into a source of energy because the enzyme M-PFK is not present. This enzyme is required to metabolise the glucose into a usable energy supply. This means that since the spaniel is not metabolising the glucose monomer, it is not supplying a usable energy to the body and so the dog can become exercise intolerant and the disease can lead to wasting of the muscles. (c2)
In affected dogs it can lead to autoimmune haemolytic anaemia, another genetic disease which sees the immune system destroying red blood cells at a fast rate, before more can be produced. As a result a suffering dog can become anaemic.
Canine Phosphofructinase has no effective treatment, meaning that the disease continues to descend through generations. At present, according to the veterinary clinical pathology journal, the PFK deficiency gene frequency in Cocker spaniels is estimated at 10% of the population (Vetgen). However, by using this statistic the chances of two carriers breeding is 1/100, one in four of these pups will be homozygous recessive and so is equal to roughly 1/400 being born with the condition. The incidence of carriers is therefore fairly high, but the probability of a pup being born with the condition is relatively low and so is not such a large problem in terms of numbers with the disorder.


Another significant genetic disease, which is seen to have a high incidence in Cocker Spaniels, is PRA, specifically central PRA, which means progressive retinal atrophy. The age of onset of this genetic disease varies and can be seen as early as 18 months and, in some cases as late as seven years (c3). It is a disease of the retina, which affects the rods in the initial stages of the disease and the cones in the later stages. With Central PRA the abnormality occurs in the retinal-pigmented epithelium and will also cause the photoreceptor cells within the eye to degenerate slowly (c4), reducing the capacity for sight in the particular dog with the disease, potentially being able to cause blindness.
Fig 1: The image on the left shows a normal and healthy canine retina, whilst that on the right shows a Cocker Spaniel with Progressive Retinal Atrophy
(Images courtesy of www.veterinaryvision.com)
In this disease P is the dominant allele whilst p represents the recessive allele. PRA is a recessive trait and so the affected allele is p, with the dominant P being normal.
Dogs with the genotype PP have normal sight, whilst dogs with a pp allele pairing have the sight threatening disease. Dogs that have a heterozygous pair of alleles (Pp) are, as mentioned above, carriers of the disease but have normal sight unaffected by Central PRA. These carriers pass on the allele for Progressive Retinal Atrophy to approximately half of their offspring.
The American company Optigen have now identified the mutation gene, which causes this type of PRA in cocker spaniels. The test is now available to breeders in Britain and also in the US, and is able to identify whether a certain dog is clear of the disease, is a carrier, or has the disease (c5). Genetic testing will be looked at later in the project.
Although a test is present to identify the disease, the disorder itself cannot be cured and there is therefore no treatment for it.


Although cocker spaniels are not primarily the most affected dog by deafness, there is evidence to show that the incidence of this is high in this breed. This is considered to be as a result of selective breeding to exaggerate their long ear characteristic, which results in the passing of a faulty allele through generations, giving rise to this disorder.
Inherited deafness in one or both ears occurs due to the degeneration of sensory inner ear structures, known as sensorineural deafness and is often due to nerve abnormalities. (c6) As a cocker spaniel gets older deafness is likely to become more pronounced, with sensorineural deafness a reason for this.
According to the vast majority of studies on the subject the faulty allele leading to deafness is directly related to the genetics of the dogs coat colour. This was particularly noticeable in cocker spaniels with large amounts of white fur, as well as those who had the piebald or merle gene. Merle can be defined as a colour combination in a coat, which is a solid base colour, usually red, brown or black with lighter blue-grey or reddish patches. In cocker spaniels it has also been recognised that blue eyes, caused by an absence of pigment in the iris, significantly increased the risk of congenital deafness.
The increased prevalence of deafness in dogs with at least one deaf ear between its two parents, compared to dogs from parents with four good ears, i.e. no deafness, supports a hereditary factor in pigment-associated congenital sensorineural deafness. (c7)
Those parents with deafness in one ear can produce offspring, which are either deaf in both ears or neither.
One of the only ways to deal with deafness and attempt to reduce the chances of it recurring in a later generation is to prevent deaf dogs or bitches from mating.
After analysing data from a research paper by Aubrey A. Webb (DVM ph.D)(c8 ), who carried out research into the number of cocker spaniels affected by sensorineural deafness, it does not seem to be a significant problem in terms of incidence in this breed. According to his data, which tested 828 cocker spaniels, 768 of them were bilaterally hearing (92.8%). The numbers, which were unilaterally deaf, were 57 (6.2%) whilst those dogs that were bilaterally deaf were 9 in number (1.1%).
This research was backed up in a published abstract, presented at the May 1996 meeting of the American College of Veterinary Internal Medicine in San Antonio, Texas (c9). They carried out the same test on 1,247 cockers, where 93.7% were bilaterally hearing, 5.4% were unilaterally deaf and the percent bilaterally deaf were 1%, meaning that the total deaf was 6.3%. As both these researches received similar data, I feel that we can reasonably accurately say that the results are reliable. This means that I can come to an informed decision that deafness is not a large problem in this breed, with only 6.3 out of 100 cocker spaniels being affected by deafness on average. However where it does occur in this breed the effects on the particular dog can be severe.
Observing these researches, we can see peer review within the scientific community. This is when a researcher or scientist sees a research paper carried out by a colleague and attempts to reproduce the research in an attempt to disprove, back up or confirm the initial researches findings.

One reliable way to determine whether a dog is deaf or not at an early age is to use what is known as a BAER test. This means Brainstem auditory evoked response. (Source: Inherited Deafness in dogs: Aubrey A. Webb) It is the same test, which is used to test the hearing of humans, involving needle electrodes on the head, and in front of each ear. Essentially, this test measures brainwaves associated with clicks of sound delivered to each individual ear. However the test cannot be used until the puppy is at least six weeks of age, as the ear canals only open a short time before this. (c10). Therefore having accurately identified a deaf dog, a breeder is able to ensure that it does not mate and pass on the faulty gene for deafness.


Another significant genetic disorder, which appears to be breed specific to the Cocker Spaniel, is Familial Nephropathy. This is a hereditary recessive renal (kidney) disease, which has, according to research and reported cases, been affecting this breed for over fifty years. Current genetic data on the European English Cocker Spaniel population indicates a frequency of at least 20 % of dogs carrying the genetic anomaly responsible for this autosomal recessive genetic disease. (c11)
Familial Nephropathy usually occurs in juvenile cockers between the age of six months and two years. Symptoms of this potentially fatal disease can be polydipsy, whereby the affected dog takes in more water, and also polyurie, whereby the dog urinates much more frequently. The deterioration of the kidney function only begins, as I have mentioned when the dog is a few months old and so for this reason it can be hard to diagnose at birth.
As the disease progresses the kidney looses its selective filter function, meaning that essential proteins and electrolytes needed for the effective functioning of the body, are lost from the dog, and also the capacity to concentrate urine, which is why more is produced, leading to polyurie. The kidney is, in very late stages of the disease, unable to excrete the waste, essentially leading to organ failure.



Although many genetic disorders cannot be cured there are a number of ways that we can lower the risk of dangerous and potentially life threatening diseases spreading to later generations.
However, many breeders of cocker spaniels and other dogs will ignore these methods by breeding from a male which has the required characteristics, without first ensuring that the dog is free from a particular disease, meaning that the frequency of the mutated gene becomes very high. This means that the genetic disease is more likely to be in a breed, and is why some diseases, such as PRA, in cockers are more common.

If scientists and breeders are able to identify a dog which is a carrier of a recessive mutation, the data and information that was collected could be used to develop breeding programmes which were then able to reduce, and potentially eradicate the disease from the breed. One way to test to evaluate whether or not a dog is a carrier of a genetic disorder is to screen for the presence of a mutated gene. Although this process is very time consuming, as each disease must often be screened against separately, if the dog tested can be clearly seen to possess one normal and one faulty allele then that particular dog is a carrier of the genetic disease which is being tested for.
As a result of the fact that, in comparison to man, we know very little about what genes cause genetic disorders in the dog, scientists and researchers often use what is called the candidate gene approach. This involves the study of diseases, which are similar in other species, such as man. (d1). This has lead to the identification of the mutant gene responsible for many genetic disorders including that of the gene causing PRA in some breeds of dog. This was found because of its similarity to the gene in humans causing a disease called Retinitis Pigmentosa and the genetic disorder in mice caused by a mutation called RDE.

Another method that can be used is the genetic map. The creation of a genetic map needs scientists to lay down markers along each chromosome, with each marker showing a unique position on one chromosome. (d1)
These markers can be used to conclude as to which markers are close to a faulty gene causing a disease, and are known as linked-markers. Since these markers are positioned on each chromosome, the linked markers will be able to narrow down the search radius for the mutated gene (d1) and in many cases the dog that possesses a particular linked marker will also possess the mutant gene, showing that the disorder is being carried in that dog.

DNA tests and screening can then be carried out. This test is based on a sample of DNA prepared from a tissue sample. Many veterinarians and scientists prefer to use a blood tissue sample, but others, feel that a tissue sample taken from the cells of the cheek, known as a buccal cell scrape will be just as effective (this was the feeling that the vets which I have worked with felt when asked, as they felt this was less invasive for the animal, and potentially safer). The sample taken from the dog being tested will have all the genes and genetic information that is present within the particular dog.
The sample is then screened, to see if there are no, one or two copies of a specific mutant gene in the dog. If the genetic disease which is being screened against is known to be caused as a result of a single recessive mutation, no mutated genes will show that the dog is unaffected by said disease. However if one mutant copy is present the animal will be a carrier, whilst if two mutations of the gene are present then the animal is known to be affected by the disease.
A bitch, which has been identified as a carrier, does not necessarily need to be removed from a breeding program contrary to what is often thought by many breeders. DNA screening can allow a dog to be found which is not affected in any way by the disease. By mating these two animals approximately half will be carriers but the other half will be ‘normal’, none of the pups within the litter will be directly affected and have the disease (See fig 2 below). This means that the line can continue by breeding from the unaffected offspring, and this will help to maintain the traits, which are important for a specific breed, such as ear length and shape in cocker spaniels. However to do this the DNA testing must be carried out accurately and must be able to be relied upon fully, otherwise, the genetic disease may not be halted from being passed to the next generation, and therefore continuing its line.



Fig 2: Mating from
a carrier female &
an unaffected male.
(Source: Kennel Club
Genetics d2)



On the other hand, the only responsible way to prevent the passing on of faulty alleles and a disease if a parent is homozygous for the faulty allele, and has the genetic disorder, is to exclude them entirely from the specific breeding programme, as the chance of the disease appearing in the offspring is high.

Another way of identifying the presence of a mutant allele is to carry out biochemical screening, measuring the level of the protein product of the gene in question. If the gene is mutated this will be highlighted by the protein level. It will be significantly reduced in carriers of the particular gene, compared to being completely absent in affected dogs. PFK, mentioned above, can readily be analysed by measuring the enzyme activity present in the red blood cells, as this particular disease is an enzyme deficiency caused by mutation of the gene for the enzyme. A dog, which is clear of PFK, will have enzyme levels that are within the expected norm, whilst affected dogs have little, often negligible enzyme activity, with carriers showing intermediate levels of enzyme activity. (d3)
However, there are problems with biochemical screening. The most significant is the fact that due to natural biological variation - normal enzyme levels for a particular dog fall within a fairly wide range and so it can be difficult for scientists and researchers to tell if a dog is a carrier of the inherited disease, or if the dog simply has a low normal enzyme activity. This has led to dogs being removed form breeding programmes because of false negative results and so this is obviously something that researchers have had to improve, to prevent this occurring. (d3)
This method is now not so often used, with DNA tests for individual genetic diseases regularly becoming available. However this method of screening, despite its problems will continue to be used for diseases which are affected by proteins and enzymes, until a more efficient and reliable DNA test can become available.
The DNA tests mentioned are used for single gene disorders, however there are genetic diseases, which are polygenic, meaning that they involve mutations in a number of different genes. Therefore clinical screening programmes have had to be developed for these conditions. One of these that is particularly relevant to the Cocker Spaniel is the British Veterinary Association Hip Scheme.

A single x-ray is taken of the dog’s hips, by the owner’s own vet. It is then sent for scrutiny to BVA orthopaedic specialists. Each x-ray is evaluated by two specialists who give a numerical value for each hip. These two values are then added together to give the dogs overall hip score. Each hip is scored out of 53, with the lower the score, the better the anatomy of the hip of the dog. (d3)
Scores for each dog are sent to the Kennel Club, where they are added to the Registration Database. The hip score will therefore appear on the registration certificates of any future progeny (offspring), allowing potential buyers to see the score that the parents attained, which could give valuable information on the average score of the pups hips, before the puppy is able to be screened. (d3)
This programme is, according to data collected by the kennel club, resulting in the breed mean hip score slowly falling each year, in the Labrador, Golden Retriever and German Shepard, which are tested most often for hip dysplasia. (Page 29 of d3) This information shows that breeders appear to be using the programme responsibly, to breed dogs with better quality hips.
It is important that all scores for pedigree dogs are submitted, regardless of quality, so that the Kennel Club can form a reliable account of dogs that have been screened, and the overall incidence of bad hips in breeds, so that a accurate picture of whether or not the breed mean scores are improving can be obtained.

As opposed to inbreeding as a particular breeding programme, there are a number of other options open to breeders, which can help to prevent, or reduce the risk of genetic inherited diseases in their breeding stock.
The first is line breeding, which occurs by mating grandsire to granddaughter, or aunt to nephew for example. Most breeders use this programme to breed pedigree dogs. Through this method, new and desired genes are slowly introduced and unwanted (both dangerous and appearance related) genes are slowly replaced. The actual rate of the gene change varies according to how strongly the breeder line breeds. (d4)
One of the main problems faced with this breeding programme is that it can take several generations for the dangerous or unwanted gene to be eradicated, and so litters which are born during this time will still show the unwanted gene if it was present in the parent. This means that if the breeder is not careful, the dangerous gene, which could potentially cause disease, will be passed on to further generations and so the programme will not have achieved any improvement to the cocker spaniel.

Another breeding programme is outcrossing. Many veterinarians see this to be the better programme in terms of genetic diversity and improving the genetic makeup, as it involves breeding a sire and dam, which are completely unrelated to each other.
With an outcross there is a larger range of alleles including coat colour, size and general appearance, as a result of the increased genetic diversity between the parents. The main reason for outcrossing is to introduce a new characteristic, into the breed. Usually the puppies retained from these outcross breedings are bred back into the breeder's original line to standardize them back into the line's general characteristics and appearance, eventually with the new desired characteristic. (d4)
One of the main drawbacks with this as a programme is that it can in fact increase the number of dogs who carry a genetic disorder recessively, meaning that there is an increased chance of the disease occurring in future generations.

I recently spoke to Elaine Thomas (d5), who is an accredited Cocker Spaniel breeder about what she is doing to improve the genetic health of her dogs. She said “I am testing all my dogs with the Optigen PRA test, as well as testing for good hips in all my stud dogs. On top of this I am testing the relevant dogs for Familial Nephropathy to ensure that my kennels stay free of this genetic disease” This shows that breeders are trying to improve the genetic health of their dogs to prevent the further increase of breed specific genetic disorders.
However when I asked Mrs Thomas what improvements could be made to improve the situation further, she said “In my opinion the cocker spaniel breed, and indeed others, will make little progress until the kennel club start taking breeding and testing more seriously, it is a well known fact that England is years behind other countries in many areas. One of the most important things to me is that when we take our dogs to be tested for good hips or for the Optigen PRA test the dogs do not have to be micro chipped, so in theory, if you took one dog that had a good result, you could take the same dog a hundred times and just give it a different name, this is a disgusting state of affairs and should be changed immediately. Micro chipping should be compulsory for all kennel club registered dogs and the kennel club should refuse to register puppies if they are not chipped- no test should be allowed without this. This does not help to improve the health and welfare of our dogs but encourages deceit and false information from breeders.” Although the kennel club gives us an image of an improved picture, many feel that this is not the case, and it is clear that, for an accredited breeder to have this view, there must be other breeders who are not taking the genetic health of their stock seriously, and this is something that I feel must be addressed before we can move forward in terms of the genetic health and welfare of our dogs.

The major body that is acting to improve the breed standards of all pedigree dogs is the Kennel Club. Jeff Sampson, a canine geneticist from the kennel club said on the Pet Care show (d6), “we've been visiting these breed standards and taking any words out of that breed standard which could be open to misinterpretation in terms of exaggerated breeding.”
Caroline Kisko, secretary for the Kennel Club said on the same show that if a breed standard is to be altered the decision goes to a committee, which includes a vet. This means that a vet can have the final say. If he or she believes that this change to the breed could cause potential problems then the proposed change to the breed standard does not go ahead.
The Kennel Club is attempting to protect the well being of dog breeds, essentially by ensuring that any required feature within a breed must take that particular dogs health into consideration. For instance with Cocker spaniels, the Kennel Club evaluates whether their ears, for example, are detrimental to their health, ensuring that the breed remains as healthy as is reasonably achievable (the use of the ALARA principle)
One of the biggest problems that the kennel club is trying to eradicate is the use of a ‘popular sire’ as mentioned above, and, on a smaller scale, the very close in breeding between brother and sister, which greatly reduces the gene pool and makes contracting a genetic disease more likely.
Jeff Sampson again said, “There are breeds which are really just varieties basically, the only difference is a one gene difference between various breeds. And we're now thinking about ways of broadening that concept to allow those breeds some degree of inter-breeding to perhaps reinvigorate their genetic gene pools”, in other words increasing the gene pool within a breed. This method can apply to Cocker Spaniels, who can be bred with working cockers, which are in reality a very similar breed, as I have said, it is in fact registered as the same breed by the kennel club.
Increasing the idea of widening gene pools and diversity within a breed, the kennel club and other governing bodies, now allow semen from donors abroad to be used in matings in this country, in the attempt to reintroduce diversity and ensure that we do not proceed further down the road of dangerous genetic diseases by reducing the gene pools of breeds.

Another rather more extreme method of reinvigorating the genetic diversity of the species is to take a particular gene from a particular animal, and then transplant this gene into the cocker spaniel. Since DNA has the same structure in each species, the sections of this molecule will be able to be transplanted into the recipient without being rejected. On David Attenborough’s programme Charles Darwin and the Tree of Life (d7 ), Attenborough said that implanting a gene from a jellyfish, which makes the animal luminous, into a mouse will display the same characteristic in the mouse; it too will become luminous.
Therefore, although it has not yet been extensively carried out, it would potentially be possible to transplant a gene for sight from any animal into a blind or partially blind, cocker spaniel. This could potentially allow blindness to be eradicated from the breed. The technique has, for the first time been used on humans, with tests successful in the lab and on animals. Dogs that had the defect had their sight improved so much after the gene trasplantation that they could walk through a maze alone. (d8 )

However with a treatment such as this, there will always be ethics to consider. Is it right to take a gene from a living animal and implant it into another? Also we must consider the fact that if this treatment were to go ahead, where would scientists have to draw the line. Effectively breeders and owners could use this method to create designer dogs, for example with a specific coat colour, which would even further reduce the genetic diversity of a breed and make the problem which pedigrees face even greater.
This treatment, if to be considered, would have to be strictly monitored to ensure that it was not used for situations such as this. However it is an area of genetics, which could produce results that improve the health of dog breeds around the world, and perhaps should be looked into further by researching bodies, to be used in animals.

When considering selective breeding and genetic engineering, it is important to take into consideration what is the best action to take in the interest of the dog.
For example, many feel that the test offered by Vetgen, allowing breeders to select mates who will produce predictable coat colours within the litter (d9) allowing undesirable coat colours to be avoided, is unacceptable. This is still selective breeding, but will further reduce the diversity of a breed. We must think, ‘is this helpful to the breed, or is this simply being done for our own benefit?’ If it is the latter, this testing should not go ahead and a law should be passed against this act.

Another ethical issue raised through selective breeding is what features should be selected for, and does the Kennel club as an authorising body really have a right to do so. I feel that we should not selectively breed, purely for the fashionable features that may be possible with breeding, as again it is of no benefit to the animal.

One of the greatest issues that is raised, is whether or not, when reducing the gene pool through selective and inbreeding, we are reducing the range of alleles and so could potentially be loosing alleles in future generations, which may be of significant benefit to the animal in the future. (d10)


Having spoken of the role that breeders must take to improve the genetic health of the Cocker Spaniel breed, we must also consider what veterinarians can do to help the situation to improve.
Veterinarians should help to present and inform of the issues surrounding genetics and the effects that they can have, to any owners who wish to start breeding and indeed offer advice to breeders who are already in the business. It is also important that they continue to work, with geneticists, to develop more specific tests for individual genetic diseases, so that these can be incorporated in a responsible way into the breeding programmes of individual breeds.
Another way that veterinarians can help to improve genetic health is to act in a responsible manner, and encourage all owners of dogs who are screened for hips and elbows etc, to submit the results regardless of the vets own assessment of quality. Some vets have persuaded owners to refrain from submitting the results because of the belief that they will not pass the screening for being able to breed from that dog. However this is irresponsible and unprofessional and if this continues will mean that the problems relating to hip dysplasia for example will not improve and will continue to be a problem for future generations.


The issue of genetic diseases will continue to become more of a threat to our breeds if the entire canine community does not work together.
Breeders must continue to work with the interest of the genetic health of their dogs in question, and not simply on the success of a potential champion in the show ring.

The Kennel Club and associated clubs in Europe must also ensure they do everything within their power to improve genetic health, they must address any issues and take control and responsibility for the health of a species that man has come to love.
The extent of this must continue to spread to judges of the show ring, preventing a dog with serious health risks from winning acclaimed prizes, as this will only succeed in encouraging breeders to ignore the work that others have put in to improve canine health- undermining everything that geneticists are attempting: To essentially eradicate the genetic disease.
For this to happen judges must have a more extensive course in recognising poor health in a show dog, as I feel that the current course offered by the Kennel Club is inadequate. One cannot learn how to recognise a healthy dog in just a few sessions, and this is something that needs to be seriously reviewed, if the show ring is going to maintain any credibility in the canine world.
Vets and geneticists must also ensure that as much information is given as possible on the dangers of continued selective breeding for desired characteristics, to ensure that any new breeders are fully aware of the issues surrounding pedigree dogs.
It is of the up most importance that scientists, geneticists and biochemical-veterinarians continue to work to provide specific DNA tests for genetic diseases, as this, according to many in the profession, is the way forward in ensuring that the breeding of dogs can take place without using dogs which are carriers of the genetic diseases. The more DNA tests available for each breed, the more likely we are to be able to eradicate these diseases from the breeds, thereby taking the long road to reinvigorating the gene pools of our pedigree breeds.
Another area linking to this is the Dog genome project, which is becoming more and more important in identifying the chromosomes and genes responsible for particular diseases as well as their locus, allowing the DNA tests to be developed. This project will be essential in the near future, as we attempt to right the downward path that we ourselves have taken through the extremely controversial process of selective breeding.


Appendixes:

2 Basic Genetics, genes and alleles:

The nucleus of each cell contains genetic information to enable that particular cell to function effectively. The information, which allows all life to develop, is called deoxyribonucleic acid, or DNA. A gene is now known to be a section of DNA molecule carried on a chromosome. Chromosomes occur in pairs in all nuclei within a cell, except the sex cells. This means that after reproduction, a chromosome from one parent will be able to pair up with a chromosome from the other parent. This ensures that the dog receives half the genetic material from each parent, and should effectively lead to diversity within a species, provided that inbreeding does not take place.
The dog has 78 chromosomes, in 39 pairs, on which a large number of genes are located, (Source: AQA AS Biology: Nelson Thornes) which makes up the dogs genotype.
Each member of a gene pair is called an allele. A gene can have a wide range of alleles within a population but an individual animal will have only two alleles, which influence or result in a particular trait. If the two alleles are identical the animal is homozygous at that locus; if the alleles are different, for example, Aa, then the animal will be heterozygous. (Source: Kennel Club genetic definitions: Found on website and in Dogs, Dog breeding and the control of Inherited disease in the dog.)
If the allele for a particular trait is dominant only one copy is needed to show that particular characteristic. However if the allele is recessive then two copies of the alleles are required. (Canine Inherited Disorders Database) In genetics we use upper case letters to portray the dominant allele and lower case letters to portray the recessive allele. Therefore, using this model, either Aa or AA will express the characteristic, whilst for a recessive allele trait; only aa will express the particular characteristic in the dog.

The dog, which is a heterozygote, will be a carrier of the disease, but will not be affected by it, meaning that the harmful allele, with a negative trait is passed down to offspring through generations.


















BIBLIOGRAPHY

a1 Animals in the Womb: Channel 4, Nov 2008
a2 www.thecockerspanielclub.co.uk/breedstandard.htm. (Accessed November 2008)
a3 Wikipedia (Search: English Cocker Spaniel- section on Working Cockers.) (Accessed November 2008)

b1 http://www.medterms.com/ (Accessed December 2008)

c1 As above
c2 Vetgen (www.vetgen.com/canine-pfk.html) (Accessed December 2008)
c3 The cocker Spaniel Club. (http://www.thecockerspanielclub.co.uk/)
c4 http://www.veterinaryvision.com/ (Accessed December 2008)
c5 Optigen (http://www.optigen.com/opt9_test_prcd_pra.html) (Accessed December 2008)
c6 http://www.animalhealthcare.ca/ (Accessed December 2008)
c7 www.lsu.edu/deafness/recent.htm (Accessed December 2008)
c8 Research paper on Deafness by Aubrey A. Webb (DVM ph.D)
c9 Published abstract, presented at the May 1996 meeting of the American College of Veterinary Internal Medicine in San Antonio, Texas.
c10 http://www.dfordog.com/ (Accessed December 2008)
c11 Antagene (antagene.com-From home page: Dog-Genetic Diseases-Familial Nephropathy) (Accessed February 2009)

d1 http://www.basc.org.uk/ (Accessed February 2009)
d2 Image courtesy of http://www.thekennelclub.org.uk/
d3 Dogs, Dog breeding and the control of Inherited disease in the dog. A Kennel Club Publication 2006 Biochemical Screening-page 23 Hip Scheme pages 27-28
d4 http://nrta.com/breddforfoundation/breedingfor.html#out (Accessed February 2009)
d5 Elaine Thomas Accredited Cocker Spaniel Breeder.
d6 Pet Care Show
d7 David Attenboroughs Charles Darwin and the Tree Of Life BBC 1 Sunday February 1st
d8 http://www.telegraph.co.uk/ February 2nd 2009
d9 Vetgen (http://www.vetgen.com/) (Accessed February 2009)
d10 AQA AS Biology Nelson Thornes


Genetics of the Dog - Malcolm B. Willis. (General information on Hip Dysplasia-p144 Genetics of the eye-PRA p224-226 Genetics of the circulatory system and other related systems-Canine Phosphofructinase p251 Miscellaneous conditions Chapter 13-Deafness p275)
Control of Canine Genetic Diseases – George A. Padgett DVM. (General reading)

Correcting Behaviour in Horses

Recently I was called to go and see one of the horses that belonged to the horse whisperer who I have been working with.
The horse had had a visit from the vet who was attempting to file down her teeth, a task which must be done every 6 months to a year. This occurs as nowadays we let horses graze on grass whereas when wild they would consume more rough coarse foods which would naturally wear the teeth down.

When the vet arrived, the mare ran away and it was extremely difficult to catch her in order to apply the brace and begin filing. This was, as the horse whisperer said, entirely his own fault as he had not been applying the dualy regularly, so that as a result the horse had come to associate this with being caught.
Once she had been caught, the vet was unable to finish his work as she reared up twice. At this point the vet was asked of he could stop and come back another day to finish her teeth. This was due to the fact, as I have said previously, that it only takes three repetitions of that behaviour for it to become learned.

The following weekend I attended with the Horse Whisperer to attempt to correct her behaviour so that she would not run off when approached with the dualy.


My first step was to go into the field with her with the dualy, attempting to approach her. Immediately it was clear that she was uncomfortable and she moved away from me. Geoff then told me that when I approached again I must keep up with her, walking briskly alongside. When she stopped I stopped too, holding the position for a short time, not making eye contact, before backing away. This method is known as pressure and release and I have talked about this briefly in previous posts. The process is then repeated. If the horse turns and walks away again, it is important to again keep in stride stopping immediately when the horse stops.
The reason that we back away from the horse is that this is a action that a predator would not do, and so by doing so we show the horse that we do not mean any harm and are not a predator.
With time the horse will become used to the human presence and will not walk away. At this point, we approach slowly in a relaxed manner stroking the horse with the dualy and moving away. This can be done several times, until the trainer feels that the horse is comfortable with the sensation of the collar on its neck.
As we progress, dualy is placed over the horses nose, held in position for a short time and then removed. if this stage of the process proceeds well then the dualy is fitted. At this point it is important to monitor the body language of the horse. Is it comfortable in this situation? If so the lower lip may stick out, and the head will be slightly bowed.
Leading work can then be performed to ensure that the horse will be ready for the visit of the vet.
This is often a long and slow process, but the rewards when you manage to correct behaviour from disliking the head collar to eventually walking with head collar and leading without a rope are amazing.
All this showing that the majority of the time we can be calm and gentle with large animals achieving the results we want, without unnecessary force or strength.