Lucas Terrier Club

Breeding Philosophy and Health

BREEDING PHILOSOPHY

Whilst many breeders of Kennel Club registered breeds may disagree, the fact that the Lucas terrier is not KC registered and, therefore, we do not have to subscribe to a closed registry system, we feel is very much to the breed's advantage.

When breeds become recognised by a Kennel Club the founders are registered and thereafter it is quite unusual for new blood to be added (not impossible, as it has been done from time to time and the addition of new Sealyham blood to the Cesky terrier gene pool springs to mind). However, if the number of founders in a breed is small and possibly has already become rather inbred in the quest to produce a particular look ('type') then the closing of the door to further new blood inevitably leads to future generations becoming increasingly inbred.

This situation may then be exacerbated if there are some males considered to be particularly good examples of the breed and over-used for stud purposes as this leads to the 'popular sire' effect. Simply, if the vast majority of puppies are sired by a small nucleus of dogs then room for manoeuvre in future generations becomes increasingly difficult. This can also lead to the loss of different genetic material carried by dogs not related to these popular dogs because they never have the opportunity to be bred from.

If the popular dogs have deleterious health related recessive genes it is inevitable that puppies displaying the symptoms of whatever condition these dogs may be carrying will be seen when progeny from the same root stock are bred together. Some of the puppies inherit two copies of the recessive and, therefore, become affected by the condition.

There are other issues associated with close inbreeding that may not be noticed by individual breeders or in the breed generally until it has become a major problem. These can be litters becoming smaller, an increase in neonatal and postnatal mortality, dogs dieing short of the previous average lifespan and an increase in the number of infertile animals.

The way to avoid these occurrences of negative genetic problems (which are present in all breeds and types of dog) is to allow additions of new blood and curb the overuse of a small number of sires. In this way, the gene pool is kept diverse and the coming together of parents carrying the same recessive will not happen on a regular basis.

We accept that the Lucas terrier is not a 'cookie cutter' dog, we have a mix of different types. We do want the dogs to be recognisable as a Lucas, and it is a goal in the breeding programme. However, the quickest way to establish breed type is to inbreed and, as is explained above, there is a cost to this. As guardians of the breed we have to ask ourselves if we want the dog to pay the price. I think the answer would be 'No'.

Dogs that phenotypically (in appearance) suit one another for breeding are scrutinised on paper to check how closely related they are. If the Co-efficient of Inbreeding is more than 10% then the mating would not be recommended.

Perhaps the best description of the Lucas terrier breeding programme is that we have taken the scenic route, a little slower and bit more meandering, rather than straight down the motorway, but we are heading to the same destination and will, hopefully, arrive relaxed and in better condition!


HEALTH

The main health issue that occurs in Lucas terriers is a lumbar problem called IVDD - this is the most common neurolgic syndrome seen in the dog, particularly those that are chondroplastic (long and low). In 2007 two young dogs were put to sleep due to paralysis in the hind legs and one older dog was operated on and has recovered to a degree.

Because dogs walk on all four legs jarring forces are normally applied at a right angle to the spinal column. However, when dogs jump down onto their front legs, the major line of force is redirected down the length of the spinal column causing greater end-on compression of individual discs and an increased likelihood of herniation. Additional twisting forces are greater where the immobile thoracic spine meets the mobile lumbar spine. So, the most common site of disc herniation in the back of the dog is the mid-back junction where the spinal cord is present and becomes compressed by herniated disc material. This can lead to major paralysis in the hind legs from the resulting spinal cord damage.

Key signs of mid-back disk herniation, unfortunately, are usually quite acute. With almost no space for herniated disk material to occupy, the spinal cord can be severely squashed. If the disk is just starting to protrude but hasn’t actually herniated, the dogs will walk with an arched, stiff back due to pain. They may cry out when picked up or their back muscles are squeezed. They may be reluctant to move out of their beds and will not want to go for a walk. If more pressure is present on the spinal cord, uncoordinated movement and some paralysis of the hind limbs can be seen as the dog drags its toes and walks with a wobbly gait. Further pressure on the spinal cord causes total hind limb paralysis and eventually loss of deep pain sensation if left untreated. The quicker the dog can be operated on the better as the longer the dog is left without surgical intervention the more permanent damage the spinal cord sustains.

It is recommended that puppies are not allowed to jump up on people, run up and down stairs, go on and, worse, off furniture or beds and to jump in and out of cars. Puppies and adult dogs should be kept at the correct weight and not be allowed to become fat or obese. It’s not, as is mentioned above, the jumping up but the jumping down that causes the damage. If your dog is trained to wait to be lifted out of a car it can also be a life saver from the point of view of there being less chance of it diving under the wheels of a passing vehicle.

I have been in touch with Clare Rusbridge BVMS DipECVN MRCVS, an European and RCVS Specialist in Veterinary Neurology to discuss strategies for dealing with this condition. Perhaps unsurprisingly most of the studies into IVDD has involved Dachshunds, and in 1980 a project conducted by Havraneck and Blazaretti in Switzerland which consisted of an x-ray study of 209 examples of this breed aged between 12 months and 18 months gave strong evidence that calcified discs tend to herniate and that calcifations are hereditary. Then, the Stigen project in Norway covering the period 1991 - 1996 involving the study of x-rays of 327 Dachshunds aged 12 to 18 months concluded that Dachshunds with calcifiations at the age of 12 months had a four times greater risk of back problems than dogs without calcification and, again, that disc calcification is hereditary.

So, how to proceed?

Below is a short extract from the Danish Veterinary Surgeon, Vibeke Jensen's, thesis (approved 28th September 2000):

Development of Intervertebral Disc Calcification in the Dachshund: A Prospective Longitudinal Radiographic Study [Journal of the American Animal Hospital Association, 7/2000]

The development of calcification was monitored in 40 Dachshunds from eleven litters using x-rays. The dogs were x-rayed at the ages of 6, 9, 12, 18 and 24 months and some also at the age of three or four years. The study showed that the first calcifications were already visible at 6 months of age but the highest number of calcification appeared when the dogs were between 12 and 18 months old. After 24 months there were few new calcifications and only in dogs that already had several. Many of the calcifications were hardly visible before the age of 24 months, but could be clearly confirmed at that age. Calcifications started to disappear at the age of 18 months, and that phenomenon accelerated after 24 months. The disappearance of the calcifications was more common in dogs with several calcifications. At the age of 12 months 53% of the dogs had confirmed calcifications and 7% were suspected cases. At the age of 24 months 80% of the dogs had calcifications (averaging approximately 3.2 calcifications per dog). Of the calcifications, 80% were in the thoracolumbar (mid-back) area.

Pamela Harrow spoke to Clare Rusbridge about the above study and Clare agreed that a way to proceed would be to xray prospective breeding stock when they are 18 - 24 months old (the timing, as shown above, being important). Any dog with four or more areas of calcification should be excluded from the breeding programme.

IVDD is not a major problem in the Lucas terrier, but those considering owning one should be aware of it, and those who are breeding should be seen to be making an effort to ensure it doesn't become an issue. We recommend that breeding stock should be x-rayed and any dogs with 4 or more areas of calcification are not bred from. In fact, it is recommended that all owners should have their dogs x-rayed so that they are aware of any potential problems.

Other than the above the Lucas terrier has no significant health problems. That does not mean that other health issues do not crop up from time to time, of course they do. One person has reported their dog has hip dysplasia, one person has reported their dog has juvenile cataracts and two people have reported their dog has primary lens luxation but in terms of a percentage of the entire population these are not significant issues for us currently. Now that Sealyhams are being DNA tested for PLL we will be in a better position to keep this condition out of Lucas lines.