Breeding out dun - what's the best way?

[tussock]

I know that dun is dominant and I'm working on breeding out (or really introducing more colors among them dd) the dun in one of my breeds. First generation is Dd, nothing strange about that. But then I breed back on the grandsire which is DD. The outcome from there could be either DD or Dd, so far I've breed those three times with different colored horses to try out if they are DD or Dd. It's not enough, clearly since all foals so far has been dun.

So my question really is if there's any color of horse I should try to breed to to get more visible dun markings - some dun foals has very pale dun but are nevertheless dun? Or are I'm tackling this issue the wrong way? Would it be better to breed solid (dd) part breeds of the breed before breeding back to the grandsire?

[BlackOak2]

I know that dun is dominant and I'm working on breeding out (or really introducing more colors among them dd) the dun in one of my breeds. First generation is Dd, nothing strange about that. But then I breed back on the grandsire which is DD. The outcome from there could be either DD or Dd, so far I've breed those three times with different colored horses to try out if they are DD or Dd. It's not enough, clearly since all foals so far has been dun.

So my question really is if there's any color of horse I should try to breed to to get more visible dun markings - some dun foals has very pale dun but are nevertheless dun? Or are I'm tackling this issue the wrong way? Would it be better to breed solid (dd) part breeds of the breed before breeding back to the grandsire?

You may be tackling it a little hard. From what I've seen so far, light color breeds light color (like if you have light colored chestnuts and you breed them to light colored chestnuts, you'll mostly get more light colored chestnuts)... so you probably have a trait offering lighter colored duns. You could try breeding into a black line... a lot of my duns show much stronger marks when they come out a grulla color, rather than a chestnut-colored dun. I'd also recommend staying away from pearls, champagnes and creams because that can make dun coloring that much harder to see. If you know for a fact that your grandsire is DD, then it will take at least two generations to breed out the DD, but that's just the best case scenario.

If you want to breed out the dun completely, but want to keep the grandsire's genes, I'd suggest taking your best foals from him and breeding out to corresponding horses that 'look the part' for what you want (or have the BR you want) and that have no dun (or just breed him to non-dun carriers). Then only keep the foals that have what you want (regardless of dun, they'll be Dd) and breed out again to non-dun carriers. From that point you have at least a 75% chance of having no dun offspring (they may still throw a Dd).

I hope this helps.