what if Some breeds of beef cattle have two color options, red and black, where the black version of the gene (B) is dominant over the red version (b).

The different forms of the beef cattle color gene are called?

The different forms of the beef cattle color gene are called alleles. In this case, the red allele is represented by the lowercase letter "b," and the black allele is represented by the uppercase letter "B." These alleles have different versions or variants that can be inherited from the parents and determine the color of the cattle.

BB or bb, homozygous; Bb, heterozygous.

I hope this is what you were asking for.