Coat Colour Basics in Highlands

I

3 heifer photo

have been asked to write an article for the newsletter to attempt to explain the basics of the genetics behind colours in Highlands. When we first started breeding Highlands I was somewhat perplexed by the various colours that calves would turn out to, be given the colour of the sire and dam. After some research and analysis of a few thousand registered calves’ pedigrees, I now have a much better understanding of the basic concepts of what controls colour. Having said this, there are still a number of anomalies that have not been explained at this stage.

If you would like more detail, and a look at colour photos, then refer to our website (www.bairnsley.com) and follow the colour article links at the bottom of the home page. This article is written with the help and guidance of Sheila Schmutz from the University of Saskatchewan, Canada who is an incredible source of information on colour genetics, especially in Highland cattle.

Black Vs Red:

The first concept to understand is that there are only two base colours in Highlands – red and black (both controlled by the ‘E’ locus of the 18^th chromosome), and all other colours are variations of these based on a few other influencing genes. Black (E^D) is dominant to red (e) and this means that an animal with one black gene, and one red gene will appear black.

The other main gene that affects colour is the Highland dilution gene (D^h) which appears to act in a similar way to some dilution genes in other breeds. At this locus, one dilution gene will cause red to become yellow, and black to become dun. If there is the full compliment of two dilution genes, red becomes white (white animal with a pink nose) and black becomes silver dun (basically a white-haired animal with a grey nose, black hooves and black horns).

The only other gene known to commonly affect colour is the brindle gene. Some specific work has been done on the gene that controls this in Highlands and is as yet unpublished. One brindle gene gives rise to light brindling where the black stripes on the background red colour are mainly noticed around the face, and will be more obvious in summer when the coat is short. The full compliment of both brindle genes is thought to cause heavy brindling where there is nearly as much black stripe as there is red between.

The Australian Highland Cattle Society only recognises 6 colours – red, black, yellow, dun, brindle and white. Silver dun is quite a rare colour and probably wasn’t fully understood when the society was founded.

Calf colours:

I am often asked about how to pick which colour a calf will end up being as an adult. This is not always an easy task. There is a link on the website to show a few of these changes that can occur but some interesting things that we have noticed include:

– red and yellow can appear distinctly different as new born calves, or nearly the same.

– black and dun animals can be born close to their adult colours or a chocolate colour (but they still have the black pigment on the nose and hooves).

– coat colours can go through some dramatic changes in the animal’s first 12 months of life, thus making it difficult for novice breeders to know what colour to register them as. Either ask someone experienced for help, or accept that you might register them as the wrong colour (happens a bit in the herdbook).

2-tone calf

(Two month old black calf, born chocolate & changing colour)

Some unusual things that crop up in Highlands:

* Particolour is a colour seen in nearly all countries in the world and only appears very occasionally and therefore is fairly assumed to be a recessive gene. These animals potentially can be registered in the Australian herdbook, but to my knowledge I do not know of any that have.

* Bus dubh (or ‘black muzzle ring’) is a distinct black ring seen in females around the muzzle and from what I can tell may either have something to do with the brindle gene, or more likely something to do with what is known as the ‘wild type’ (E⁺) red colouring that exists on the E locus with the red (e) and the black (E^D) genes. ‘Wild type’ is dominant to red, but recessive to black. It is impossible to distinguish it from the red colouring however, so it is rather academic. It does appear to have been the original colour of the cattle that roamed Europe (Aurochs) thousands of years ago.

Bus dubh head shot

(Bus dubh colouring around muzzle)

* I am aware of a few breedings of two red animals that have given rise to a black calf, but none that have had parentage confirmed with DNA analysis to disprove the worry about the black Angus bull from next door jumping the fence. Now this would not be possible going by what we currently understand about the E locus in Highlands, so we assume that there may be another gene masking the black colouring on the E locus in the sire or dam, or maybe there is a separate, as yet unidentified, recessive black gene.

* Coat length can affect the colour that we see! Animals with longer coats (genetically, or those in winter coat) will appear lighter in colour as the tips fade the longer they get. Part the hair and look down at the skin level to see the real hair colour.

This is a rather brief summary of colours and about as good as we can do in a black and white newsletter. Feel free to contact me if you had any questions or have seen any anomalies that you can not easily explain.