Dewsnap Ponies

What is a coloured horse?

A coloured horse is one which carries certain genes. The main ones being Tobiano and Overo. In the UK the most common colour pattern is Tobiano.

Because of quite recent genetics development there is debate over what exactly constitues a true genetic 'coloured' horse. At the moment any horse or pony with a patch of white bigger than 6 inches above his elbow or stifle level can be registered as coloured, however these horses are often Sabino or carry the 'splash' gene, both of which are realitively unidentified and unpredictable, unlike tobiano and overo. Sabino and 'splash' markings appear regularly on pure bred welsh, arabian and heavy horse breds, all who exclude piebald and skewbald animals from thier purebred registars.

What is the differance between a  Tobiano and an Overo? 

Tobiano and Overo markings are caused by different genes. A tobiano horses white markings extend DOWNWARDS from the spine between the ears and dock. An Overo horses white markings start under the belly and extend UPWARDS, rarely crossing the spine.

Overo marked horse

Tobiano marked horse

My horse has been called Tovero, is this possible?

Yes, Tovero horses are possible. This is when a tobiano patterned horse is crossed with an Overo patterned horse and the foal inherits both colour patterns. To be sure a horse has inherited both colour patterns a DNA test to test for both Overo and Tobiano genes is needed.

A tovero horse

What is the difference between Piebald and Skewbald?

Piebald is black and white ONLY. Skewbald is any other colour and white.

Someone said my horse might be homozygous for colour, what does this mean?

When a coloured horse is described as homozygous it means that the horse carries a coloured gene from his mum and a coloured gene from his dad, because he has TWO coloured genes he will always pass one onto any os his/her foals, meaning ALL foals by/out of a homozygous horse will be coloured. Homozygous horses often have 'ink spots' or 'paw print' markings which are small coloured spots within the white patches which fade at the edges. Homozygous horses can be DNA tested to be absolutely sure they carry two coloured genes. Do not be tempted to use an untested stallion claiming to be homozygous, you may be dissapointed!

So what is a horse called that only carries one coloured gene?

This is called heterozygeous. Heterozygeous coloured horses have inherited one coloured gene from one parent and a solid gene from the other. A heterozygeous horse has a 50% chance of throwing a coloured foal.

My mare is by a coloured stallion out of a chesnut mare, could she still have a coloured foal to a plain stallion?

No, tobiano is dominant, it is ALWAYS apparent if a horse carries the gene. To breed a coloured foal out of a solid mare, regardless of the colour of her parents, you must cover her with a coloured stallion.

I have a chesnut mare, can she have a coloured foal?

Yes, however you need to be aware of the statistics. These are as follows:

Heterozygeous coloured stallion x plain mare = 50% chance coloured 50% chance plain

Homozygous coloured stallion x plain mare = 100% coloured

Heterozygous coloured stallion x heterozygeous coloured mare = 75% chance coloured 25% chance solid (25% chance homozygous coloured)

Homozygous coloured stallion x heterozygeous coloured mare = 100% coloured (50% chance homozygous)

Homozygous coloured stallion x homozygous coloured mare = 100% coloured (100% homozygeous)

I have seen a heterozygeous coloured stallion advertised as having had 90% coloured foals to plain mares, does this mean my mare is more likely to have a coloured foal to him than another heterozygeous stallion with only 50% coloured foals from plain mares?

Although this may be fact it is a little misleading. ANY heterozygeous coloured stallion will only have a 50% chance of producing a coloured foal at each breeding. For example out of 10 matings this stallion may have 9 coloured foals, however in the next 10 matings her may only have 1 coloured foal and 9 solid foals. Never be misled into thinking you are more likely to get a coloured foal from any heterozygeous stallion rather than another.

 

If anyone has any futher queries about coloureds please do not hestitate to contact me via phone, email or via the online query form.