The spotted colour pattern of the Knabstrupper.  

For two consecutive years now Figaro has sired around 85% spotted foals.

This is a proven fact, despite differing views - especially from Germany -  pointing to the “fact” that Mendel genetics make this impossible and that we don’t know our Mendel. 

Of course we do and know everything there is to know about Mendel genetics.

It is easy to forget that we are talking about statistics allowing for Figaro to continue producing 85% or more full spotted leopards each year throughout his lifetime.

The question as to why some Knabstrupper stallions produce more coloured offspring than others is far more interesting.  There are still people who tend to prefer crossbreds and who omit to discuss this properly, maybe because their hearts have fallen to a certain stallion.   This approach, in its own way, can present a seemingly legitimate argument because, for example, it increases the number of bloodlines in the breeding programmes.

In the process, however, it is easy to forget why the purebred Knabstrupper is so important for the continuity of the spotted pattern.  

I will therefore in the following explain why some Knabstrupper stallions are much more likely to make coloured offspring than others (we are familiar with the pedigrees of all of them). The explanation does not pretend to be exhaustive.

In accordance with Anglo-Saxon tradition, the gene for the Knabstrupper colour will be referred to as the Lp gene (for Leopard):-

1.      Firstly, it must be remembered that it is not the spots that are passed on but the holes in the white colour blanket. Therefore the more white colour blanket a Knabstrupper passes on, the higher the chances that the next generation offspring will have spots.

2.      The amount of white colour passed on by a Knabstrupper will be primarily determined by two factors: 

a.             has it inherited a single or double portion of the Lp gene and 

b.             how many colour affecting helping genes (or modifiers) has it inherited.

3.   There are a number of  indications of the Lp gene being present:  

a.       a white sclera around the iris, 

b.       mottled skin around natural openings and

c.       spots. 

A Knabstrupper can have so much white colour that a. and b. are the only indications.  Last year Figaro sired a completely white coloured colt (Fremi, Dam: Lusy) without any indications of spots or other-coloured hairs whatsoever. 

It can of course also have so little white colour that it is totally, for example, black like the Dam (Kamma) of a full spotted black leopard of Figaro’s also from last year (Sheik).

4.   Traditional Mendel genetics tell us that the chances of a heterozygote (for the Lp gene) Knabstrupper passing on the Lp gene to its offspring are 50%, thus either the offspring inherits it or it doesn’t.  It also tell us that a homozygote (for the Lp gene) will pass on the Lp gene in 100% of the cases, no matter which breed it is crossed with. 

Until now it has been almost impossible to tell visually whether a less than 50% white patterned Knabstrupper is a homo- or heterozygote.  From experience, only time and offspring can determine this.

5.   Today we know that Mendel genetics do not cover every eventuality.   

A horse inherits many genes affecting the colour, not only one or two. We know that the Lp gene is incomplete dominant, which means that two Lp genes, as in the homozygote, have an additive effect in blocking of pigment to the skin and hair. This means that a single Lp gene will block some pigment, but spots can still be breaking through in white areas. Two Lp genes will stop almost all pigment being formed in skin or hair and none or very few spots will show.

6.  We now also know that the Lp gene has a host of modifying genes that will increase or diminish the white colour pattern. Offspring will inherit around 50% of these gene modifiers from their respective parents. The exact mix and amount of modifiers in each parent is determined by thousands upon thousands of past generations.

The effect of the Lp gene is best described as a light bulb on a dimmer switch, with the modifiers turning the dimmer up or down. Because offspring will inherit around 50% of the modifiers from their parents – and never in the same combination - we will never see two Knabstruppers who have exactly the same colour pattern. Identical twins do not exist

7.  Therefore, if we breed Knabstrupper to Knabstrupper, we will maintain a much higher number of the modifying genes, than if we breed Knabstrupper to non-Knabstrupper. 

The latter, having no relevant modifiers, consequently can not pass any on, with the resultant foal only inheriting modifiers from its one Knabstrupper parent. 

This also explains why the 25% solid coloured offspring resulting from Knabstrupper to Knabstrupper is still valuable as breeding stock, because they have inherited almost a full compliment of the modifiers.

8.  The result of focusing too much on the crossbreds (for example “spotted warm bloods”, “sportstruppers” and “royal tigers”) whilst neglecting the gene bank from the purebreds, is that it will not be many generations before the white colour pattern will disappear.  This will leave only horses with a. and b. from point 2. above and only with solid coloured skin, or lightly spotted horses with a lot of roaning of head, neck and legs. 

Back in the early seventies a couple of full spotted Danish leopards were shipped to Australia and New Zealand. It would be very interesting to establish just how many full spotted Leopards they have today.  Unless they have well managed breeding programs with Appaloosas who have the same Lp gene, it is unlikely that there will be any left by now.

9.  It is also important not to forget the unique and beautiful temperament of the Knabstrupper, which will also be lost in the process of cross breeding, leaving people to buy a ‘wolf in sheep’s clothing.’

10. Now let us return at last to Figaro.

      He is probably the most purebred, full spotted Knabstrupper stallion ever.

      By counting the number of Knabstrupper ancestors in his 5^th generation and by establishing that in his 4^th generation 14 out of 16 ancestors carry the Lp gene with the modifiers and in his 3^rd generation all his ancestors carry them, it is easy to see  why this is likely to be the case and why he factually pass on the spotted colour pattern to a higher than average number of his offspring.

In summary, with so much evidence in favour of the need to maintain colour through ‘pure breeding’ of the Knabstrupper, this has to be a consideration that will be close to the heart of all those with an interest in this breed, in whichever country they may reside.

Basra, Iraq

2004.01.21

Torben

top of page