Genetic Color Cross Problem?

Q: I have a dun mare which I was considering breeding this year to a buckskin stallion. I was informed that there might be some problems with this particular cross due to the dun color factor. The foal might be lethal white or albino.

A: Answering a question about crossing a dun mare with a buckskin stallion is a bit tricky because there are differences in what people mean by these terms. However, the particulars of this question can be answered without actually seeing the horses involved. Both buckskin and dun are dilutions of the horse's base color. They appear to be controlled by two separate genes, but neither gene is associated with lethal white. Lethal white primarily occurs in overo horses as a genetically recessive condition. A test for carriers of the overo lethal white condition now is available. There is another form of lethal white in horses, but that condition (which is an embryonic lethal) involves the mating of two pink-skinned, white horses.

The buckskin-to-dun mating likely would not produce an albino foal, either. Again, the genes involved cause a dilution of pigment, not a lack of pigment as occurs in albinos. True albinos are very rare, if they occur at all, in horses. The buckskin by dun cross could produce a cream horse with pale or blue eyes, but this is not a defect except in the opinion of some horsemen.

Stay on top of the most recent Horse Health news with FREE weekly newsletters from Learn More