Rex Otter belly color

Question
We have been raising and showing Rex rabbits for a little over a year and I know a bit about rabbit genetics. What I dont know (among other things) is
what the genetics of the creamy belly color of Otters thats listede as preferred in the Standard.
Most of my otters have a white belly but some now are starting to show a nice creamy belly. A judge at a recent show made a fuss over it and all the other breeders wanted to know more about breeding for that creamy belly and I dont really have a clue.

Thanks Very much in advance.
Vin King

Answer
The creamy belly comes along with heavier rufous modifiers. If you breed for intense otter markings (i.e. the red areas), the belly will get darker (i.e. creamy coloured) along with the richer otter markings. You can best do this be breeding to better coloured otters; breeding to castors or opals with very rich intermediate band colour; or breeding to blacks, blues, chocolates, and lilacs that are very dark in colour. To get really rich self colour, there has to be a high amount of red pigment in the coat. Now, the red pigment is all mixed in with the black-brown pigment in selfs, so you cannot see it directly. However, you can see its effect because the self will be darker and richer in colour than a self without a lot of red pigment.

You can also breed to richly coloured (Again with that needed creamy belly) reds, though it will run the risk of producing tort otters, which are not showable. For some people, though, the tort otters are worth getting the rich colour in the regular otters.