View Full Version : EBVs and Unscanned Stud Dogs
9th August 2009, 07:39 PM
Comments welcome on the question posed below.(also posted on CC)
I wonder what you think of the scenario that the dog with the best EBV for many breeding bitches may turn out to be an unscanned dog?
By dint of many clear scans - mostly by show breeders - an unscanned dog may be heading the list of producing most clear offspring.
How would that sit with those who:
1. Set great store in EBVs and the giving of results to make this project work
2. The fact that an un-scanned dog ( considered by many here and 'over the way') to be an absolute no-no) may be the best choice for many bitches using this scheme.
9th August 2009, 11:09 PM
Well, theoretically and eventually it will not matter that the dog is not scanned because of its EBV... but that is only if there are eventually EBVs linked to a successful result from the genome scan, geBVs.
There are two issues there as I understand it directly from explanations by Sarah Blott and Clare Rusbridge:
1) EBVs are less accurate the fewer overall scans that exist on a range of dogs. More scans mean better and more accurate EBVs for everyone internationally.
2) EBVs without the genome element are nowhere as precise and I do not believe any responsible breeder would breed to an unscanned stud until EBVs are much, much further down the line.
Sarah Blott explains it here:
Using EBVs allows us to distinguish between higher and lower risk dogs in the grading categories A-C. EBVs can be calculated for most dogs even if they have not been MRI scanned, as long as they are related to dogs that have been scanned.
All dogs will have an EBV at birth but the EBV may be modified by the dog’s subsequent clinical record or MRI scan and by information coming from other relatives. The EBV becomes more accurate as information on offspring becomes available, because we start to gain insight into which half of the sire and dam genes were actually inherited when we see transmission of the genes to offspring. The accuracy of the EBV increases with numbers of offspring and this may take some time to achieve. In contrast, genomic breeding values (geBVs) provide a high accuracy from birth. By looking directly at the DNA genotypes we can see which genes were inherited from the sire and from the dam, without having to wait for offspring. Genomic breeding values can be used for accurate evaluation at an early stage, before the disease phenotype may be apparent and before a dog is used for breeding.
10th August 2009, 09:28 AM
Now we come, I think to the $64,000 Question ,will the EBV Scheme work if Cavalier Breeders think that the Cavalier's name they have been given will not have a chance of winning in the Show Ring .
I think it has been proved ,that if Cavalier Breeders think that a Cavalier has no chance of winning in the Show Scene then they are not interested,
That is why a Cavalier is popular , is because of the chances of winning.
Is this the reason why this Cavalier Pretty Type of Head has now come to the fore. ...because it can win in the Show Ring ?
Will Cavalier Breeders be interested in any other Type of Head for a Cavalier ,if compatable for their Breeding Stock, ?
Interesting Times lie ahead for the Cavalier World!!
10th August 2009, 09:05 PM
My Oliver's pedigree is quite a good example of how EBV could work. His father (who was BIS at the Cavalier Club show a few years ago, but has recently died aged 12) was never scanned. But he has produced at least 2 offspring with SM, and both his father and grandfather had SM. So the existence of Oliver's pedigree on the EBV database means that his father's EBV will be adversely affected - as will that of any of his other offspring, which include a top winning Cavalier at the Westminster Show in the US. The EBV should flag up that any of this family could be either affected or carriers - treat with caution and scan before breeding!
This is why some breeders are so against EBV - whether they like it or not, their dogs will be in it through other dogs' pedigrees (and why there are legal issues to be sorted out).
Kate, Oliver and Aled
11th August 2009, 12:43 AM
Now we come, I think to the $64,000 Question ,will the EBV Scheme work if Cavalier Breeders think that the Cavalier's name they have been given will not have a chance of winning in the Show Ring.
Bet, the EBV Program allows breeders to enter the names of 5 or more dogs that the breeder wants to mate their dog with, the breeder can enter who they think will have a chance of winning in the Show Ring plus even enter some who already have done some winning. Have a read and see image examples on Carol Fowler's website via this link.
11th August 2009, 01:32 AM
Thanks for the reminder of the link to the very helpful material on Carol's website, provided in association with the key EBV researchers Sarah Blott and Tom Lewis.
I do not believe there are actually any significant legal issues to be sorted on EBVs. I know this is being thrown around, but EBVs are routinely used in livestock breeding and there aren't legal issues there -- and I have spoken to people involved who also say there are no issues in this regard -- delays at the moment are due to figuring out how the programme will be set up and administered, and to requests that MVD be included into EBVs, which has meant soliciting additional information and compiling it.
EBVs are already possible to calculate on any UK cavalier with a KC registration, as the breed is so closely interrelated and there are already heading towards 1000 MRI scans to draw upon with more being submitted all the time. But at this time they are not yet releasing EBVs for public use. Hopefully it will not be too long.
11th August 2009, 02:30 AM
Karlin thanks for that information. It appears that things are still progressing behind the scenes. Even in such things where a while back there was talk of not showing actual EBV figures but instead have some sort of colour code system for the internet access where software had to written to facilitate this. Then I see on Carol’s website images like the following which makes me think that the software might be there and ready. Plus I see in an image the mention of inbreeding which appears to be taken into account with the EBV Program.
11th August 2009, 11:28 AM
Yes ,this is a Great Idea, but having lived through many Cavalier Breeders Opposition to helping in the MVD Cavalier Problem around 20 years ago,will the EBV Scheme be any different for to-days Cavaliers.
As Karlin mentioned ,will Mandatory Health Tests be the only answer to save the Cavalier Breed.
11th August 2009, 01:51 PM
It was Sarah Blott who mentioned in her talk to the Midland Club that there were legal issues to be sorted - perhaps cattle and sheep breeders aren't as keen on infighting as Cavalier people!! I think the issue is that some breeders may say that the name of their dog has been fed into the database without their permission (because it is present in other dogs' pedigrees) and make a fuss under Data Protection - that's my guess. They'll shoot themselves in the foot, I think, since everyone will assume they've got something to hide...
Kate, Oliver and Aled
11th August 2009, 07:05 PM
Some time ago I heard something mentioned about legal issues to be sorted, maybe TODAY someone might like to contact Sarah Blott and ask her about legal issues involving with the EBV Program.
From what I have been reading there appears to be more EBV activity going on, and I wonder about legal issues even where other dog breeds are involved. The following is interesting and was mentioned at a KC meeting back in May 2009 and from this address.
21. Afternote: The following information has been provided by Prof Jeff Sampson, who is the Kennel Club Genetic Consultant. There is considerable evidence to show that using a dog’s own hip score as a selection tool will lead to a reduction in the overall breed mean hip score. However it is a complex disease and information from the dog’s own hip score can be improved by also incorporating the hip scores of its near relatives if known. For example, if a dog has sired ten or more hip scored progeny, then the average progeny hip score is more valuable as a selective tool than its own hip score. So, if all that is known is an individual dog’s hip score, then progress can be made in reducing hip scores in future progeny. However, more useful tools can now be used to predict the ‘breeding value’ of an individual dog, and two years ago the Kennel Club commenced supporting research into using these new tools, called estimated breeding values, to help breeders select mating pairs that will give more rapid improvement in the hip scores of future generations. The Animal Health Trust are using current hip score data to generate Estimated Breeding Values (EBVs) for selecting against high hip scores. Essentially a dog can have an EBV calculated based on its own score, the scores of closely related individuals and, also the scores of more distantly related dogs, although these latter scores are of less value. Mate select programmes will then be developed using these EBVs to help breeders select against producing puppies with poor hip scores.
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