The gene that causes the black pigment to be confined to the points ( the gene that causes a horse to be bay) is dominant over the black gene. So if the mare is homozygous for the bay gene she will always throw bay foals when bred to a black. If she is heterozygous then your chances are 50/50. There is no way to tell by looking at her if she's heterozygous or homozygous.
Posted on Apr 7, 2000, 9:52 PM from IP address 209.209.2.233