There are some things that anyone interested in owning a Cavador should know.
Cavadors are a cross between a Cavalier and a Labrador. It is a misnomer to use the term hybrid, but for the purpose of this article the terms will be used interchangeably.
Heterosis (Hybrid vigor) is “the occurrence of a superior offspring from mixing the genetic contribution of its parents.”
It is common to see Heterosis used to increase yield uniformity and vigor in corn, sorghum, rice, onions, spinach, sunflowers, broccoli and others.
The reason we have all the dog breeds that we have today are due to selective breeding, line-breeding, and in-breeding, Which has caused there to be distinctive traits that separate that breed from all others.The problem with this is that it has also caused many of the canine diseases that we have today.This is not to say that these breeding tools are all bad, because that wold be untrue. Without these tools dogs would would not have been able to be breed to serve the purpose that they were bred for. Whether that be Hunting, Search and Rescue, Law Enforcement, Pest Control, Companionship, etc.
Each Breed has a list of which genetic diseases and cancers that it is predisposed to. Before purchasing a pet of any breed an owner should be aware of these.
In order to see that health benefits of a Cavador we must look at all of these individually. Below is a list of the most common Genetic diseases for each respective breed.
Cavalier King Charles Spaniel:
Mitral Valve Disease (MVD)
Genetic eye diseases
Brachycephalic Airway Obstruction Syndrome (BAOS)
Genetic Eye Diseases
Exercise Induced Collapse
Cancer and Tumors
From this list we can see that are some genetic diseases that Both Labradors and Cavaliers are both predisposed to. For this reason all Breeding pairs should be tested for Hip dyplasia and have eye clearance. It would also be suggested that Labs are tested for Elbow Dysplasia and Cavaliers should have Heart and Patella testing. This is the same testing that purbreeds should undergo.
Now, this is the part where out-crossing becomes very helpful. Recessive gene diseases. All mammals have two of every gene. One from their mother and one from their father. A recessive gene trait is one that is only expressed when an individual has two copies of that gene. If an individual has only one copy of the gene they are considered a “carrier.” There are many recessive gene diseases in different dog breeds. One would think that it would be easy to get rid of these, but in many cases there is not a single individual of the breed that doesn’t have 2 copies of diseased gene. This is when out-crossing can be very helpful. By crossing one breed that only carries 2 recessive diseased gene with a breed that doesn’t have the diseased gene guarantees that that offspring will be free of that diseased trait.
Heart mitral valve disease (MVD) is the leading cause of death of Cavalier King Charles Spaniels throughout the world. MVD is a polygenetic disease (disease influence by several genes, not just one) which afflicts over half of all cavaliers by age 5 years and nearly all cavaliers by age 10 years, should they survive that long. The prevalence of MVD in Cavaliers is about 20 times that of other breeds, and in cavaliers, the onset of the disease typically is much earlier in the life of the dog. Labs do not carry the any genetic risk factors for MVD so being that the disease is polygenic and labs carry not genetic risk factors the likelihood of a early onset MVD is a cavador is virtually eliminated.
Syringomyelia (SM) is an extremely serious condition in which fluid-filled cavities develop within the spinal cord near the brain. It is also known as “neck scratcher’s disease”, because one of its common signs is scratching in the air near the neck. The back half of the cavalier King Charles spaniel’s skull typically may be too small to accommodate all of the brain’s cerebellum, which may also be too large, and so it squeezes through the foramen magnum – the hole at the back of the skull – partially blocking the flow of cerebrospinal fluid (CSF) down the spinal cord. The variable pressure created by the abnormal flow of CSF is believed to create the SM cavities – called syrinx – in the spinal cord.
In general, most small breeds have the possibility of developing SM. Researchers think it is linked to breeding smaller dogs. Something happens as the head becomes smaller and neck shorter and muzzle foreshortened that seems to trigger a mismatch in development between skull and brain size. That is the best theoretical picture at the moment, based on clinical observation, genetic work, MRI and autopsy studies and some foetal studies.
This being known. The likelihood of SM is greatly reduced by out-crossing a cavalier with a “large breed” dog since large breed dogs have no predisposition to SM.
Brachycephalic airway obstruction syndrome (BAOS), is an inherited condition in the cavalier King Charles spaniel. The breed is predisposed to it, due to the comparatively short length of the cavalier’s head and a compressed upper jaw.The symptoms may vary and range in severity, depending upon which abnormality is causing them, but they typically include labored and constant open mouthed breathing, noisy breathing, snuffling, snorting, excessive snoring, gagging, retching, exercise and/or heat intolerance, general lack of energy, pale or bluish tongue and gums due to a lack of oxygen. All cavadors will have longer muzzles than Cavaliers and therefore will have less problems associated with this.
Lab and Cavaliers are predisposed to different eye diseases. A cross between the two provides a larger genepool to help eleviate some of these problems. Most of the eye problems in Cavaliers are thought to be attributed to the brachycephalic shape of their heads. Labs do not have the same type of skull structure so this reduces the risk of eye problems. That being said, Dam and Sire still should be tested and registered with CERF.
Centronuclear Myopathy (CNM), or hereditary myopathy, begins in Labrador puppies and climaxes at about 1 year old. This disease is similar to Muscular Dystrophy in human children. It is a recessive gene disease, and since cavaliers have no diseased genes it would be impossible for a Cavador to get CNM.
A syndrome of exercise intolerance and collapse (EIC) is being observed with increasing frequency in young adult Labrador Retrievers.Affected dogs can tolerate mild to moderate exercise but 5 to 15 minutes of strenuous exercise induces weakness and then collapse. EIC like CNM is also a recessive gene disease so it would be impossible for a Cavador to get EIC.
Labs are predisposed to many cancers and tumors including Mast cell tumor, Cutaneous histiocytoma, Sq. cell carcinoma, Nasal cavity tumors, Insulinoma, Lymphosarcoma, Limbal melanoma, Oral Fibrosarcoma, Thymoma. Some of these are less life threatening than others but all reduce the quality of life of pets. Cavaliers are one of the few breeds that are not predisposed to any particular cancers or tumors, So Cavadors should have a reduced risk of tumors and cancers.