The Companion Animal Welfare Council in the UK has produced a
comprehensive report on "Welfare Aspects of Modifications,
through Selective Breeding or Biotechnological Methods, to the
Form, Function, or Behaviour of Companion Animals". What that
translates to is a consideration, from an animal welfare
perspective, of breeder responsibilities in producing animals
for a pet or show market -- eg should clubs do more to protect
breeds from known genetic probelms by more strictly controlling
access to regsitration. Sweden for example will not give full
registration to cavalier puppies whose parents have not been
properly tested for cardiac problems, according to the MVD
breeding protocol. Two of the issues considered and used as
examples is syringomyelia and MVD in cavaliers. These are
considered particularly relevant to ths study because cavaliers
are by far the most popular toy breed in Britain and one of the
most popular breeds overall. The report can be downloaded here.
It is a fairly large pdf: Here's the app