When examining DNA results there are three results which are reported:
Clear - which means that the dog is completely free of both the disease and also does not carrying the gene which will produce the disease.
Carrier - this means that the dog does not have the disease but carries the gene which may produce the disease. A dog that is a carrier of a disease can be mated with another that is clear and all of the progeny from this litter will be free of the disease. Under no circumstances should a carrier of a disease be mated with another carrier or affected of the same disease.
Affected - A dog has the described disease. An dog which is affected with a disease can be breed with another dog that is clear of the same disease and all of the puppies from the mating will be not affected with the disease but will all be carriers.ELBOW DYSPLA
Border Collies are generally very fit and active dogs having the ability to work stock very well. Most Border Collies today do not have to work stock and need to channel their energy and intelligence into many other activities. These include obedience, agility, ball work, frisbee, showing and being a highly active pet and family member.
Most breeds, including the Border Collie, will occasionally suffer from illnesses and diseases. There are a few diseases that Border Collie breeders and owners shoulder be cognisant of including a number of hereditary diseases that can be found within the breed. In many cases there are DNA tests that are available so that reputable breeders can test their breeding stock to ensure that puppies are not affected.
Hip Dysplasia
Hip dysplasia is a genetic disease that primarily affects large and giant breeds of dogs but can also affect medium-sized breeds and occasionally small breeds. It is primarily a disease of purebreds, although it can also occur in mixed breeds. Hip dysplasia is a developmental condition that results in an abnormal looseness or laxity of the hip joints (the term dysplasia means abnormal growth). It results in the defective development of the hip and femur (hip joint) and a degenerative process of the same. Dysplasia is a multifactorial disease. It has a strong genetic component, with a very high rate of heritability, as well as a number of environmental factors, such us nutrition or behavior. It seems to be demonstrated that an over-activity when pups, been accommodated on slippery floors or a diet promoting a too quick growth may be also involved in causing this health problem.
To understand hip dysplasia and the resulting arthritis, you need a basic understanding of how the dog’s hip joint is affected. The hip joint is comprised of a ball and socket that forms the attachment of the hind leg to the body. The ball portion is the head of the femur and the socket is located on the pelvis. In a normal hip joint the ball rotates freely within the socket. The bones are shaped to perfectly match each other with the socket surrounding the ball. To strengthen the joint, the two bones are held together by a strong ligament. The joint capsule, a strong band of connective tissue, circles the two bones to provide added stability.
This is a normal hip joint:
Hip dysplasia is linked to abnormal joint structure and a laxity of the muscles, connective tissue, and ligaments that would normally support the dog’s hip joints. As the disease progresses, the articular surfaces of the two bones lose contact with each other. This separation of the two bones within the joint causes a drastic change in the size and shape of the articular surfaces.
This is an abnormal hip joint:
Border Collie Health
Most dogs who eventually develop hip dysplasia are born with normal hips, but due to their genetic make-up the soft tissues surrounding the joint develop abnormally. This leads to the symptoms associated with hip dysplasia. The disease may affect both hips, or only the right or left hip.
Hip dysplasia in Border Collies causes afflicted dogs to walk or run with an altered gait, similar to a bunny-hop. They begin to resist any movement that requires full extension or flexion of the rear legs. They will experience stiffness and pain in their rear legs after exercising and on first rising in the morning. Climbing stairs becomes difficult if not impossible. Some dogs will limp and are less willing to participate in normal daily activities, including walks they formerly enjoyed.
It appears that the amount of calories a dog consumes, especially during its fast-growth period from three to ten months, has the biggest impact on whether or not a dog genetically prone to hip dysplasia will develop the disease.
Obesity can increase the severity of the disease in dogs that are genetically susceptible and the extra weight will intensify the degeneration of a dog’s joints and hips. Dogs who are genetically prone to hip dysplasia and also are overweight, are at a much higher risk of developing hip dysplasia and eventually osteoarthritis.
Exercise can be another risk factor. Dogs genetically susceptible to hip dysplasia may have an increased incidence of the disease if they are over-exercised at a young age. Moderate exercise like running and swimming is best for exercising young dogs.
The Border Collie, unlike other breeds, does not usually display physical signs of hip dysplasia. Although they may appear to have normal and good movement, Border Collies on x-ray examination can reveal if they are affected by hip dysplasia and to what degree. Unless breeding stock are x-rayed and scored Breeders are unable to verify whether their line is clear and that they do not have a problem with hip dysplasia. If breeding dogs have been scored and the results are low then they may consider that they have a reduced chance of producing a severly affected animal. All breeders should as a minimum x-ray breeding animals and submit all x-rays for scoring. All results should be submitted to obtain a true breed average and a true reflection to the degree that the Border Collie is affected by hip dysplasia.
HEALTH AND GENETICS OF BORDER COLLIES
Neuronal Ceroid Lipofuscinosis
Neuronal ceroid lipofuscinosis (NCL) is a neurodegenerative disorder which affects people, dogs and other animals (e.g. cattle, sheep, horses).Typical for neuronal ceroid lipofuscinosis is accumulating of lipopigments (ceroid and lipofuscin) in lysosomes. Clinical symptoms can be observed in border collies quite early, around 15th month of a dog age. The beginning and clinical course of the disease vary greatly and are very individual. The rate of neurodegeneration increases together with the age, with psychical abnormalities and ataxy usually developing in all affected dogs. Increased restlessness, aggression, hallucinations, hyperactivity and epileptic attacks can be observed as well. Accompanying symptom is damaged retina due to lipopigment storage. Most affected dogs lose their ability of normal muscular coordination during training, walking and feeding. Affected young border collies rarely survive more 28th month of age (Studdert et al. 1991).
NCL is inherited autosomally recessively which means that the disease develops only in those dogs who inherit mutated allele from both parents. Carriers of mutated allele (heterozygotes) are clinically healthy but transmit the mutation on their descendants. In case of mating two heterozygous dogs there is a theoretical chance that 25% of descendants will be absolutely healthy, 50% will be carriers a 25% will inherit from both parents mutated allele and therefore will be NCL affected.
The mutated allele can be screened for by DNA testing. Dogs tested clear cannot pass on NCL to offspring.
Collie Eye Anomaly (CEA)
Collie eye anomaly (CEA) is a congenital, inherited, bilateral eye disease of dogs, which affects the retina, choroid, and sclera. It can be a mild disease or cause blindness. CEA is caused by a simple autosomal recessive gene defect. There is no treatment. The most often affected breeds include Rough Collie, Smooth Collie, Border Collie, Shetland Sheepdog, Nova Scotia Duck Tolling Retriever and Australian Sheepdog. CEA is caused by an abnormal development of the eyeball, starting at about day 30 of the embryonic development. Postnatally, different defects are found depending on the severity of disturbances in three layers of the eye.
All dogs affected by CEA have choroidal hypoplasia, by definition. CEA is not a progressive disease like prcd-PRA and most affected dogs may only have mildly impaired vision. More severely affected dogs may have pits (colobomas) affecting the retina and nearby tissues and in the most severely affected eyes, retinal hemorrhaging and detachments can occur, resulting in blindness.
Trapped Neutrophil Syndrome (TNS)
Trapped Neutrophil Syndrome is recessively inherited syndrome affecting Border Collies. Due to this mutation the correct function of white corpuscles - neutrophils - is impaired. Neutrophils are necessary parts of immune system of an individual. They take part in fighting bacterial infections and are important participants in acute inflammation. Neutrophils are produced by bone marrow and after maturing they are gradually released into the bloodstream.
In dog affected with TNS, the neutrophils are produced and mature correctly in bone marrow, but are not released into the bloodstream. If neutrophils are missing in the bloodstream and tissue, it is difficult for an individual to fight infections. The immune system is slowly failing. The failing of immune system can be seen in pups from as early as 2 weeks old and the pups die or are euthanized by approx. 4 months of age. The first symptoms may include apathy, loss of appetite, diarrhoea or poor mobility. Other symptoms depend on the type of infection the pup happens to contract.
By timely detection of the carrier of this disease unwanted mating of two carriers and birth of affected pups can be avoided.