Geneticists recently identified a new color gene "Wild Type Coat Color Allele". Both reds & blacks can have it, blacks only have visible signs if they are Homozygous for the Allele - making them brownish (different than the diluter gene).
Red cattle can have black nose, black around eyes, ears & tail.
"Many Simbrah and most Brahman have the wild type and also Brown Swiss, Tarantaise, and Jersey. A brindle also has a wild type allele. Many red breeds carry the brindle gene but it is not expressed unless the animal has a wild-type allele. Most European (fullblood) Simmentals do not carry the brindle gene. Red breeds like Hereford, Red Angus and some red Simmentals may also carry the brindle gene but it is not expressed unless combined with a wild-type. Some Red Angus and Red Simmentals have one copy of the wild-type Extension. They often have a black nose."