Improving the health of the breed and producing healthy puppies (while maintaining temperament and breed type) is one of my goals as a breeder! Orthopedic Foundation for Animals (OFA) makes recommendations about health testing for each breed. For Collies, it only recommends DNA testing for Progressive Retinal Atrophy (PRA), Multi Drug Resistance (MDR1), and Dermatomyositis (DMS). Collie Club of America breed club recommends DNA testing for the 3 previous DNA tests mentioned, as well as Collie Eye Anomaly (CEA).

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I aim to go above and beyond in health testing my dogs. I have used Paw Print Genetics in the past, but they have merged with another company. CHF currently recommends the UC Davis Collie Panel. I also aim to do OFA hips and elbows on my dogs -- even though it is not required, it's important to me to make sure my dogs are orthopedically sound, since I would like them to be able to be versatile and participate in performance. That being said, it's not a red flag if Collie breeders don't do them -- but consider if it's important to you.

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Collie Eye Anomaly (CEA)

• A genetic disorder of the eye found in multiple breeds, most frequently in herding dogs. It is estimated to exist in about 80% of the Collie population and is generally mild (the mild form is choroidal hypoplasia). It can present, however, with different degrees of severity (this is why puppy eye exams are so important!). All Collie puppies should have an eye exam. Most dogs with CEA today have no vision defects, thanks to multiple generations of breeding only the least severely affected dogs. CEA also does not worsen over time, which is why a puppy eye exam is sufficient for CEA grading. CEA does have a DNA test, however this will only tell you whether a dog is CEA Affected, CEA Carrier, or CEA Clear (Normal-eyed) -- it does not tell you the grade of CEA and does not replace an eye exam. CEA is an autosomal recessive disorder, which means a dog requires two copies of the mutation to show symptoms.

• I know from the outside, people are confused as to why Collie breeders are not breeding away from this more. It is because there is such a high prevalence in the breed and there are more serious health conditions. There are some non-conformation breeders who are touting breeding for normal eyes, but their Collies are often a poor example of the breed. There are certainly some conformation breeders who are making strides in this area. It is not a red flag for breeders to have CEA affected dogs in their program. I would consider it a red flag if someone is ONLY breeding for this.

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Multidrug Resistance 1 (MDR1)

• A genetic mutation found in most herding breeds that makes the natural barriers in the body more permeable. This means, in most cases, that affected collies may react negatively to some medications. The mutation is very common in collies: depending on the source, 55 to 70% of the collie population is affected by this mutation. MDR1 is an autosomal dominant genetic disorder, which means that only one copy of the gene is necessary for the dog to be affected. There is therefore no such thing as an MDR1 carrier. While dogs with two mutant genes are more severely impacted by the mutation, dogs with one mutant and one normal gene are still at risk of adverse effects from common veterinary drugs.

• Washington State University’s PrIMe Laboratory is the leader in MDR1 research in the United States, and has a list of veterinary drugs affected by MDR1 (see link below). Importantly, drugs affected by MDR1 are ivermectin and its derivatives. While these drugs are known to be safe at levels used to prevent heartworm disease, higher doses such as the ones used to treat mange have lead to neurotoxic effects. Other examples of drugs to look out for are loperamide (immodium), cyclosporine and many chemotherapeutic agents. Symptoms of MDR1-related neurotoxicity include weakness, lethargy, ataxia (loss of coordination), disorientation, tremors, seizures, blindness, and death.

• MDR1 doesn’t just affect the brain. P-gp is also present in dogs’ guts, liver and kidneys. In the gut, P-gp restricts absorption of drugs while, in the liver and kidneys, it promotes their excretion. MDR1 mutant dogs therefore absorb more and excrete less drugs than their unaffected counterparts.

• Recent research has shown that MDR1 status also affects cortisol metabolism and could contribute to disruption of hypothalamic–pituitary–adrenal axis regulation, and be a factor in developing Addison’s disease.

• Most breeders just treat all Collies as MDR1 affected and are careful about what drugs they use with them -- this is a good strategy, and again, it is not a red flag for breeders to have MDR1 affected dogs. Personally, I think we don't know all the effects of MDR1 yet and it is a disease that worries me much more than for instance CEA. It is something I am aiming to breed away from in my breeding program.

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Dermatomyositis (DMS)

• An autoimmune disease of both the skin (derma-) and muscles (myo-) that occurs in both humans and dogs, especially collies and Shetland sheepdogs. The disease is characterized by the appearance of skin lesions, generally first on the face and legs. Lesions appear early in life, sometimes as young as 7-11 weeks of age. Disease onset seems to be linked to stress, such as vaccination or owner surrender. Most affected dogs will develop lesions by 6 months of age, and maximum severity is reached at 1 year. Progression seems to be variable: some mildly affected dogs will only develop few lesions.

• Until recently, no DNA test was available to help track or diagnose DMS. It was proposed to have an autosomal dominantmode of expression with an incomplete pattern of expression. DMS was called the “breeder’s nightmare” as it would pop up, seemingly out of nowhere.

• The genetic test is a “RISK ASSESMENT” test and not a genetic marker test. In DMS, there is no such thing as “normal”, “clear” or “carrier”. The best any dog can be is low risk. This means they can still get it or pass it along. This also means that dogs who are moderate or high risk could still never get it. In the DMS risk assessment test, the upper case letters represent risk alleles, while lower case letters represent “wild” or normal alleles. In short, the more high risk (uppercase) alleles a dog has, the higher the risk of developing DMS.

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Progressive Retinal Atrophy (PRA)

• Progressive Retinal Atrophies or PRAs are a group of degenerative diseases affecting the retina of the eye. In the retina are cells specialized in detecting light: those are photoreceptor cells. In dogs affected by PRAs, these cells degenerate over time (atrophy), which leads to blindness. This syndrome is unrelated to Collie Eye Anomaly (CEA).

• Collies (rough and smooth) have a unique type of PRA not found in other breeds, called rod-cone dysplasia 2 or rcd2. PRA-rcd2 is a very early onset retinal atrophy, as by 6 weeks of age affected puppies can already present with night-blindness. By6-8 months, most affected puppies are completely blind.

• First identified as a disorder in the 1970s, it was quickly identified that PRA-rcd2 is an autosomal recessive disorder, which means two copies of a defective gene are needed to show symptoms. It took until 2006 to identify the mutation, and a test was later developed by to identify it easily.

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Degenerative Myelopathy (DM)

• Degenerative myelopathy typically occurs in older dogs, 7 to 14 years of age. It is a relentlessly progressive disease of the spinal cord. The first signs are loss of coordination (ataxia) and weakness in the hind legs. One rear leg is often worse then the other. The disease starts as trouble rising in the rear legs and weakness, and progresses to wobbly rear legs. Over time the rear legs become weaker, buckle, and have trouble standing or walking. Eventually, the disease progresses, over months to a couple years, to complete paraplegic. Lastly, fecal and urinary incontinence occurs, with front leg weakness. Amazingly this disease is not painful.

• The mutation identified as a risk factor for Degenerative Myelopathy has incomplete penetrance, which means that not all at risk dogs will develop the disease. Only a postmortem biopsy can truly diagnose DM. The test for this mutation is included in the UC Davis VGL Collie Panel available at a reduced price for Collie Health Foundation members.

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Cyclic Neutropenia (CN)

• Cyclic neutropenia (CN), also known as cyclic hematopoiesis or Gray Collie Syndrome, is a genetic disorder that affects the immune system. It is colloquially named after the characteristic dilute color of affected dogs, ranging from dark pewter to silver gray. Affected collies have cyclic fluctuations in the number of neutrophils, a type of white blood cell. These episodes happen every 10-12 days and leave the dogs extremely susceptible to infection, which may manifest as diarrhea, fever, bleeding, joint pain, eye lesions and stunted growth. Most affected puppies die in the first few weeks after birth.

• Cyclic neutropenia is an autosomal recessive disorder, which means two copies of the mutation are required to show symptoms. A DNA test exists to identify any carriers of the mutation, which was discovered in 2003

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Health Links

• Collie Health Foundation - breed health foundation

• Orthopedic Foundation for Animals (OFA)

• Collie OFA Recommended Tests/CHIC Program Requirements

• Collie Club of America Health Statement

• Collie Eye Anomaly (CEA)

• Multi Drug Resistance 1 (MDR1)

• MDR1 Problem Medications

• Dermatomyositis (DMS)

• Progressive Retinal Atrophy (PRA)

• Degenerative Myelopathy (DM)

• Cyclic Neutropenia (CN)

• Collie Health Video Seminars