Have only this misinformed, factually incorrect view on whether to scan dogs or not?
http://www.cavalierhealth.co.uk/scanor not.htm
Much of this is out and out untrue and it is strange to have it there on the site as the *only* piece of information offered from a breeder perspective (unless the intention is to deliberately confuse?). Surely intelligent breeders wish for something more substantive and balanced, much less current?
Where in the world did this garbled information come from? For example, no study ever conclusively showed, or claimed to show, that head shapes had 'nothing to do with SM'. A limited initial study showed no direct connection of outward shape but even that showed some connection -- see
http://www.roycroftinformationcente... InfoCenter Health SM MRI to Skull Comps.html
(perhaps the writer has never actually read any of the papers?) but several studies since including the foetal tissue research funded directly by the UK CKCS Club shows head shape, in terms of internal skull shape and development, does indeed seem very likely to be a source of the problem -- a mismatch in internal skull development and brain development. In addition researchers do believe there is a relationship between the shape of the very back of the head, the occiput (as opposed to whether a dog simply has a large head or small head) and dogs with SM. But, because of ear set and fur on both cavaliers and Brussels Griffons, the breeds that have been studied, it is very hard to see actual head and skull shape to start with. Xrays are more useful, as Laura Lang has shown on her site of xrays and MRIs (see the link above, which is very thought-provoking and interesting).
There also is not any major disagreement on 'the way forward' between Dr Rusbridge and Mr Skerritt. The way forward is establishing the BVA scheme and EBVs and supporting research to determine the genetic cause and NOT to continue breeding affected dogs or dogs that scan really poorly. The only issue of disagreement (which would be normal between professionals) has been only one of degree over which dogs should continue to be used for breeding given what they both strongly agree is a dire situation for the breed if left unaddressed. Dr Rusbridge wrote a proposal (at the request of breeders) that she feels best balances limiting the spread of ever more severe forms of CM/SM while keeping the genetic pool as wide as possible and fitting the MVD protocol. Mr Skerritt takes a far more compressed view of which dogs should be bred and feels breeding any dog with a syrinx or herniation should not be done. I certainly haven't seen much preference amongst breeders for Mr Skerritt's more restricted recommendations even though he does scans for so many breeders, much less a major rush to support Dr Rusrbidge's SM breeding recommendations. What this statement really seems to want to be is a 'get out of jail free' card to allow people an excuse to do nothing whatsoever, while artificially setting up some supposed conflict between researchers.
As for A dogs producing SM and SM dogs producing clears -- first off, basic high school genetics would predict this could happen, but also predicts the low likelihood of either, especially the latter. In addition, there's a body of actual breeding data now that is showing strongly that clear dogs are related to clears, affected dogs are related to affecteds, and that A crossings produce few affecteds, while D and F dogs produce many affecteds and as far as I know at last count, no clears at all.
And no pun intended, but grades are thrown around by many breeders cavalierly... when most of these dogs have NEVER actually been graded. These are only assumed grades based on scans by neurologists who are not part of the scanning group who issue grades. These are mostly breeder assumptions of grades, and there's never an indication as to when the dog received the (assumed) grade and how close it was to the breeding (eg was the dog an A a year ago? Three years ago? 'Graded' at under 2.5?).
Finally the concluding paragraph makes no sense. A perusal of Sarah Blott's own explanation on the CKCS Club site, or indeed the same cavalier health UK site (http://www.cavalierhealth.co.uk/ebv.htm), or Carol Fowlers' Cavalier Campaign website:
http://www.cavaliercampaign.com/ebv.htm
would help this writer to understand that scans are currently PART of the EBV scheme and are necessary to actually produce the EBVs in the first place :sl*p: (so by not encouraging scanning, this sadly would risk creating EBVs of poorer quality for other breeders who may wish to use them, due to less data on which they can be based, and means, hypocritically, that the writer is happy to have all the rest of us who have paid to scan, create the EBV program for their benefit). And of course the whole point of EBVs is to reduce and eventually eliminate the need to scan for *breeders* (although scans will still be needed to diagnose affected cavaliers).
The writer and all others who are similarly confused are fortunate though that their website has information on a seminar to be held shortly in Bristol on the current situation with SM, research and EBVs -- and so could learn and then correct this poor information. Also someone with a better informed perspective might help breeders make decisions rather than spread misinformation.
If the site wishes truly to be a resource on CKCS health, rather than appear as a whitewash, how strange to have this lopsided, limited information on such a central health issue in the breed!
http://www.cavalierhealth.co.uk/scanor not.htm
Much of this is out and out untrue and it is strange to have it there on the site as the *only* piece of information offered from a breeder perspective (unless the intention is to deliberately confuse?). Surely intelligent breeders wish for something more substantive and balanced, much less current?
Where in the world did this garbled information come from? For example, no study ever conclusively showed, or claimed to show, that head shapes had 'nothing to do with SM'. A limited initial study showed no direct connection of outward shape but even that showed some connection -- see
http://www.roycroftinformationcente... InfoCenter Health SM MRI to Skull Comps.html
(perhaps the writer has never actually read any of the papers?) but several studies since including the foetal tissue research funded directly by the UK CKCS Club shows head shape, in terms of internal skull shape and development, does indeed seem very likely to be a source of the problem -- a mismatch in internal skull development and brain development. In addition researchers do believe there is a relationship between the shape of the very back of the head, the occiput (as opposed to whether a dog simply has a large head or small head) and dogs with SM. But, because of ear set and fur on both cavaliers and Brussels Griffons, the breeds that have been studied, it is very hard to see actual head and skull shape to start with. Xrays are more useful, as Laura Lang has shown on her site of xrays and MRIs (see the link above, which is very thought-provoking and interesting).
There also is not any major disagreement on 'the way forward' between Dr Rusbridge and Mr Skerritt. The way forward is establishing the BVA scheme and EBVs and supporting research to determine the genetic cause and NOT to continue breeding affected dogs or dogs that scan really poorly. The only issue of disagreement (which would be normal between professionals) has been only one of degree over which dogs should continue to be used for breeding given what they both strongly agree is a dire situation for the breed if left unaddressed. Dr Rusbridge wrote a proposal (at the request of breeders) that she feels best balances limiting the spread of ever more severe forms of CM/SM while keeping the genetic pool as wide as possible and fitting the MVD protocol. Mr Skerritt takes a far more compressed view of which dogs should be bred and feels breeding any dog with a syrinx or herniation should not be done. I certainly haven't seen much preference amongst breeders for Mr Skerritt's more restricted recommendations even though he does scans for so many breeders, much less a major rush to support Dr Rusrbidge's SM breeding recommendations. What this statement really seems to want to be is a 'get out of jail free' card to allow people an excuse to do nothing whatsoever, while artificially setting up some supposed conflict between researchers.
As for A dogs producing SM and SM dogs producing clears -- first off, basic high school genetics would predict this could happen, but also predicts the low likelihood of either, especially the latter. In addition, there's a body of actual breeding data now that is showing strongly that clear dogs are related to clears, affected dogs are related to affecteds, and that A crossings produce few affecteds, while D and F dogs produce many affecteds and as far as I know at last count, no clears at all.
And no pun intended, but grades are thrown around by many breeders cavalierly... when most of these dogs have NEVER actually been graded. These are only assumed grades based on scans by neurologists who are not part of the scanning group who issue grades. These are mostly breeder assumptions of grades, and there's never an indication as to when the dog received the (assumed) grade and how close it was to the breeding (eg was the dog an A a year ago? Three years ago? 'Graded' at under 2.5?).
Finally the concluding paragraph makes no sense. A perusal of Sarah Blott's own explanation on the CKCS Club site, or indeed the same cavalier health UK site (http://www.cavalierhealth.co.uk/ebv.htm), or Carol Fowlers' Cavalier Campaign website:
http://www.cavaliercampaign.com/ebv.htm
would help this writer to understand that scans are currently PART of the EBV scheme and are necessary to actually produce the EBVs in the first place :sl*p: (so by not encouraging scanning, this sadly would risk creating EBVs of poorer quality for other breeders who may wish to use them, due to less data on which they can be based, and means, hypocritically, that the writer is happy to have all the rest of us who have paid to scan, create the EBV program for their benefit). And of course the whole point of EBVs is to reduce and eventually eliminate the need to scan for *breeders* (although scans will still be needed to diagnose affected cavaliers).
The writer and all others who are similarly confused are fortunate though that their website has information on a seminar to be held shortly in Bristol on the current situation with SM, research and EBVs -- and so could learn and then correct this poor information. Also someone with a better informed perspective might help breeders make decisions rather than spread misinformation.
If the site wishes truly to be a resource on CKCS health, rather than appear as a whitewash, how strange to have this lopsided, limited information on such a central health issue in the breed!