Choosing a Stud Dog 2 (continued from page one)

Elbow scores
The official KC/BVA scheme for elbow dysplasia scoring is still comparatively new. Therefore a number of very good stud dogs have not necessarily had this done. However, this will probably become commoner over time. The genetics appear to be polygenetic, as with hip dysplasia, and environmental factors also play a part. Currently there are no progeny testing records available. The scoring is different, to the hip dysplasia scheme, with a score of 0-3 on each elbow with 0 being free from disease and 1 being only slightly affected and probably still being suitable for selective breeding.

Eye Certificates
The BVA/KC eye certificate has to be renewed annually as some of the hereditary diseases looked for only become evident later on in life. Therefore, always check that the tests were carried out within the last year. Currently Labradors are tested for Generalised Progressive Retinal Atrophy (GPRA), Central Progressive Retinal Atrophy (CPRA), Hereditary Cataract (HC) and Total Retinal Dysplasia (TRD). These should all been shown as unaffected on the certificate. The other diseases relate to other breeds so can, for all intensive purposes, be ignored. Unfortunately, there is some potential for confusion in the breed at present, as a few owners are using an alternative (European) eye scheme. Check with the Kennel Club to ascertain whether or not these alternative schemes will be recorded on the registration documents. Otherwise the new puppy owners will not have an official KC document recording the fact that you were responsible and ensured these checks were carried out prior to breeding. If using a dog normally residing outside of the UK this might be the case as different countries have different or no schemes. Where ever possible ask that the dog be screened through a KC scheme.

DNA testing
There are currently three DNA tests available to detect hereditary diseases in the Labrador that we feel are present in the UK Labrador population. The most commonly used one is the Optigen test for Prcd GPRA (see above). This can detect whether you dog is genetically clear from the faulty gene, a carrier, or an affected. Remember, the eye test can only detect whether your dog is currently clear of the disease. Not whether it is a carrier or might be affected with the disease at a later date. The down side is that the test is expensive normally over a hundred pounds. A blood sample (taken by your Veterinary Surgeon who will charge for this) or mouth swab which can be taken by you has to be sent to America. There are group sessions which bring down the cost to around £70 (depending on the exchange rate). It is therefore, best to use a stud dog who has a clear certificate as then even if your bitch is a carrier or early affected none of the puppies will be affected but may be carriers. To be more sure (particularly if after research you find some of your bitches pedigree lines may have experienced problems) have your bitch tested. Even if your bitch does not come back clear this does not necessarily mean she cannot be mated but some precautions have to be put in place on the puppies’ registration documents precluding mating (which can be registered at the Kennel Club) until DNA tested. If all carrier animals are eliminated from the breeding pool the Labrador gene pool could become so small other problems will develop but you do need the advice of a good breeder to guide you through the strategies. (see links page for more information).

The second DNA test is for muscular myopathy (Centronuclear Myopathy Type 11). This has recently been found to be more common in the UK than was originally thought. Puppies become affected by the disease at 14 weeks to six months of age and have to be put down as they become paralysed. There are tests available in France and at the Animal Health Trust at the Royal Veterinary College and at around £30 per test are well worth having done particularly if you have working lines in the pedigree. Increasing numbers of British Labradors have been tested for this disease. If everyone does it it could easily be wiped out. Again, if you have a carrier dog or bitch they can still be bred but must be mated to a tested clear dog and the progeny endorsed on their registration "progency not eligible for registration" The breeder can lift the endorsement once the pups have been tested. (See Links page for more information)

The third test is for Exercise Induced Collapse EIC. This condition is probably more widespread than people realise but it can be present in dogs without them showing any symptoms as it is not until the dog undertakes strenuous exercise that it might (and only might) show signs of wobbly legs or collapse. Although the occasional death has been reported most dogs recovere within 5 or 10 minutes and many often learn to compensate for the disease and pace themselves better. However, we still feel it is better to try and erradicate this problem and are gradually having all our stock tested. (see links page for more information). There are 2 other DNA tests available for OS MRD and Narcolepsy niether of these conditions have been identified in UK labradors. A new DNA test for Nasal Hyerkeratosis which can cause crustiness of the nose and or pads has also recently been developed. It is likely many more DNA tests will be developed in the future.

There is also a DNA test for a slightly more "designer dog" gene. The SD2 gene is a recessive gene and when both parents carry the gene it can cause labradors to have shorter legs than normal. Depending on the influence of other genes that make up the skeleton the appearance can range from looking practically normal to have legs that are very short, rather like a bassett. If a dog or bitch is a carrier it is desirable to mate to either with a mate with good length of leg or one that has been tested clear for SD2. There are no health problems associated with the gene but in its extreme it is rather anoying to have a very short legged labrador although there have been at least two field trial champions with very short legs.

Colour
Labradors are generally whole colours of either black, yellow or chocolate. You can get different shades of yellow (cream through to fox red) or chocolate (milk to plain) and blacks can have different colour undercoats (the fine downy hairs under the main top coat) which can influence the strength of black and sometimes make them look rusty when moulting. However, you should not get mixed colours on the same dog although a small white spot on the chest is permissible.

Labrador coat colour genetics are not too complicated. Black dogs might only throw black puppies but some can also throw yellow or chocolate puppies when mated to certain bitches. The stud dog owner will most likely to be able to tell you if their black dog can throw yellow or chocolate. There are however, one or two rules to remember because of the genetics involved. Two yellow dogs mated together can only produce yellow puppies. It is very undesirable to mate yellow and chocolate dogs together because it is possible to produce yellow puppies with a peculiar type of skin pigment. This can also happen even if you only mix yellow or yellow carrying and chocolate or chocolate carrying lines between the two dogs' pedigrees. Therefore, if you have any chocolate in your bitch's pedigree it is usually safer to steer well clear of any stud dog with yellow close up in a pedigree.

Some black dogs and bitches can only throw black puppies whatever you mate them to but there is no way of telling this visually prior to doing a mating (although there is a DNA blood test which can tell you this now). On the alternative side, sometimes two blacks, even where there appears to be no yellow or chocolate ancestors in their pedigrees, can give you a surprise and produce yellow or chocolate puppies. This is scientifically quite possible and nothing to get alarmed about.

If you mate two chocolates you will get chocolate puppies (it is also possible, but undesirable, to get yellows as explained above). When breeding chocolates several generations of chocolate to chocolate matings can "dilute" the coat colour or skin pigment. Therefore you may be recommended to breed with a black dog (who may or may not be able to produce chocolate) to retain a strong chocolate colour and good skin pigment in the line or for that generation of puppies. If your bitch has a chocolate parent she can produce chocolate if mated to a chocolate or chocolate producing sire. The ophthalmologist who carries out your dog’s eye test can sometimes tell you if your black bitch carries chocolate as the pigment can be seen in the back of the eye.

If you have a black dog or bitch with one yellow parent then they can definitely produce yellow if mated to the right partner.

If you want to know what colours your dog or bitch carries you can have a DNA test carried out through Laboklin (see links page)

Mating assistance
You should always book up with the stud dog well in advance of the bitch coming into season and then inform the stud dog owner as soon as your bitch starts. He or she should then be able to give you advice on how to detect when your bitch is ready to be introduced to the dog. Ongoing advice, for example, if during the mating there are difficulties and the dog and bitch are not tying, is another aspect of help you can expect from the stud dog owner. The best chance of mating success is if the dog and bitch manage to tie twice 48 hours apart and this is likely to be the main aim. Finally, you must expect to pay the stud dog owner at the time of mating (not on production of puppies) unless it is the first time the dog has been used when alternative arrangements might be made. You should be given a receipt and any other terms and conditions e.g. a free mating at a subsequent mating if the bitch does not get pregnant should be in writing. The stud dog owner will also complete their part of the litter registration form, either at the time of mating or as soon as the puppies are born.

Many stud dog owners may also be able to pass on puppy sales enquiries when they do not have puppies themselves or be able to advise you on placing puppies on breed club registers or advertising.

Hopefully the forgoing will all help you decide on the most suitable sire for your bitch's puppies.

Joy Venturi Rose MSc BA Ed (Hons) Cert Ed RVN