Highland Coat Colour - Mahogany ("Frosted")

This is one of the most interesting colours that we have seen in Highland cattle across the world. It came into Australia in a Canadian cow – Anne of Glen Aspen (Can 4463). One of her embryo calves was Molly of Dandaloo (1429), who was one of the matriarchs of our herd. While they are born a rich red colour, this slowly changes during their life in a most dramatic way.

The calves are born a rich red colour, somewhat darker than those of the normal red colour, but could be easily missed if you didn’t have a red one standing beside it. The outer coat slowly changes over the ensuing months and starts to lighten off. Interestingly the longer the coat, the lighter this outer coat becomes (see that the five month old bull calf on the right has white on his near side front leg as the wind blows it open).
 

By the time the calves are weaned, they have varying amounts of white outer coat on them, yet you can still see the deep red, mahogany undercoat around the face and elsewhere depending on the amount of white. This is about their most dramatic and contrasting stage.

As they progress from here the white outer coat begins to fall out but they are left with white on their dossan, topline and tip of tail – this gives rise to the term ‘white tips’ that a number of people have used to describe them at this age – “frosted”. This stage normally lasts until they are around 18-24 months and will vary in its expression depending on the time of year (and therefore the amount of outer coat retained) and there coat length as determined by their genetics.
 

Amazingly, with age, the white tips slowly fade and the mature animal is left with a white tip to their tail and maybe some white on their dossan. They still have quite a distinct and different colour to their undercoat however. At this stage, especially through summer when the coat is shorter, you can see that some of these animals will possess the brindle gene as well. The black stripes will be most obvious on their sides and around their eyes.

While this is a truly remarkable colour pattern, the genetics behind it appears to be quite simple. That we can establish, it appears to be a single dominant gene. This means that an animal with one gene for this coat colouring will produce the mahogany colour on average in every second calf that they have. It also appears impossible to reproduce from cattle where neither parent has this colouring. We have also never seen it associated with dilution colours (yellow or duns), although a number of other animals we have seen can have lighter shades on their dossans and tails.